Seriously............... up to 18L/100km now which is no longer funny. Fuel consumption seems to only ever go up with every tank I put through it. I used to get closer to the 500km mark out of a tank around town with some highway (which still seems crap compared to what some people claim) now its under 400km. Yes I drive it hard and use a lot of the power a lot of the time, but when i'm cruising i'm cruising. And I often use the cruise control. This is not flat out around a track. I get up to 60/80/100 as quick as possible then cruise there. I shouldn't be getting such utter garbage from a FWD KF Ei

I have replaced O2 sensor, air filter, run injector cleaner through 3 times, upper engine cleaner. Checked for fuel smell in engine bay (there is none), replaced fuel cap. Tank holds pressure, if removing the cap takes ~3-5 seconds to normalize
Car does 220kph with some extra to give so cat wouldn't be overly blocked surely
Idles fine, runs fine, very smooth, no misfires no issues. Just crap fuel economy
Adjusted handbrake so there is no drag at all. Some drag in front wheels but I don't know whats 'normal'
Tires would be in balance, no shakes at any speed. Pressures 36psi. Doesn't pull to the side. Alignment not checked but they point in a forward direction so wouldn't explain a potential ~6L/100km difference

What is everything, and I mean everything that I can check that would cause economy issues, without necessarily making the car run rubbish. I want to get to the bottom of this
Could the injectors be stuffed? miniature blackhole in the tank? car stuck in some sort of a 'warm up' mode?

I would like to keep this car, i'd even like to make it better with some moderate performance mods, followed by a 6G75 swap. But at the moment i'm looking at ~$5000/year in fuel which could literally be halved with a smaller engine'd car that still puts out more power and acceleration

Have you checked the temp sensor that runs the car rich until the engine warms up?......maybe stick it on a dyno and get the fuel mixture ratio checked......

Seriously............... up to 18L/100km now which is no longer funny.

Yes I drive it hard and use a lot of the power a lot of the time, but when i'm cruising i'm cruising. And I often use the cruise control. This is not flat out around a track.

I get up to 60/80/100 as quick as possible then cruise there.
I shouldn't be getting such utter garbage from a FWD KF Ei

Car does 220kph with some extra to give so cat wouldn't be overly blocked surely

I would like to keep this car, i'd even like to make it better with some moderate performance mods, followed by a 6G75 swap. But at the moment i'm looking at ~$5000/year in fuel which could literally be halved with a smaller engine'd car that still puts out more power and acceleration

Babying my TJ on shortish town trips gets me 14.2 L/100 km. If I hammered it constantly like you seem to do, I could get it up to 18 easily.
Most of the fuel get used in warming up and hard acceleration. Cold weather seems to up the fuel consumption. You would have to go for economy running for about 20 km to make up for one hard run up to 100 kph. (I've tried this myself)

Do some research on economy driving, or if you want to get better economy, do go ahead and buy a turbo 4 cylinder. Have you checked the economy of an Evo, WRX etc if hammered?

PS Have you really had your Magna up to 220 KPH to check the cat con??

Do some research on economy driving, or if you want to get better economy, do go ahead and buy a turbo 4 cylinder. Have you checked the economy of an Evo, WRX etc if hammered?

PS Have you really had your Magna up to 220 KPH to check the cat con??

To check the cat? no, but yes i've had it to 220 on the speedo

I'm thinking VTEC Prelude but they're expensive for what they are. Nevertheless, still get far better economy. Too bad the auto's all explode...

The point is my fuel consumption seems to go up with every tank, without me changing my driving at all. Every single tank I put through it I check the trip meter and it's less each and every time. I remember one where I had 450km to the tank, decided to put BP Ultimate through it and instantly it went to 400km, never again rose above 400. Which makes absolutely no sense whatsoever. Now its consistently under 400

Have you checked the temp sensor that runs the car rich until the engine warms up?......maybe stick it on a dyno and get the fuel mixture ratio checked......

Not sure how to check it though?
If I was going to stick it on a dyno i'd also want it tuned but is it even possible to alter the stock ECU by a tuning shop. Or does it need an aftermarket replacement?

The point is my fuel consumption seems to go up with every tank, without me changing my driving at all. Every single tank I put through it I check the trip meter and it's less each and every time. I remember one where I had 450km to the tank, decided to put BP Ultimate through it and instantly it went to 400km, never again rose above 400. Which makes absolutely no sense whatsoever. Now its consistently under 400

I've noticed a big difference in L/100 km between warm/hot weather and the cooler times of the year, about 2 to 3 L/100km. Could be seasonal fuel (does Australia have this?) or just the engine takes longer to warm up. Donno, but I'm waiting to see if it improves in Spring/Summer. Has in the past.

When I had my TJ II VR-X on 91 unleaded around town (still mainly freeway driving) i averaged 10l/100 per tank. If i put 98 Premium i could't do better than 12.5/100k under the same driving conditions. Really weird, and there wasnt any extra power that I could feel.

I get 8.7l/100k on the highway in my 3.5 manual and I love it. 10.5l/100k around town. I run 98 in it sometimes to clean it out and I have a fuel map for 98 flashed in and it gets even lower.

No have not taken it to 220 because I'm not an idiot.

My brother gets 8.3l/100k in his TJ around town.

General servicing and making sure you look after the car is the best way to make sure it holds up over time. I would suggest that it hasn't been looked after and is probably burning un-needed fuel :D

If you saw it you wouldn't say it wasn't 'looked after'. There's not a scratch on the paintwork anywhere. Engine bay is cleaner than most cars only 2 years old let alone 15. Previous owners definitely took care of it, to the point of being ridiculous.

Doesn't mean parts don't wear out though. And at 18L/100km i'm not at all convinced its my driving. Somethings not right, especially with claims of sub 12L/100km around town.
If you are going off the trip computer I don't believe it, if you are checking fuel consumed and it is genuinely that, then there is genuinely something wrong with mine and it needs to be fixed.

I'd like a break down list of everything I can check to find out why its so crap. I'm not a car person so i'm not familiar with EFI systems and how to correctly check any sensors, injectors etc

edit: you say you have a different fuel map? so the stock ECU can be flashed and tuned for optimal fuel burn?

If you saw it you wouldn't say it wasn't 'looked after'. There's not a scratch on the paintwork anywhere. Engine bay is cleaner than most cars only 2 years old let alone 15. Previous owners definitely took care of it, to the point of being ridiculous.

Doesn't mean parts don't wear out though. And at 18L/100km i'm not at all convinced its my driving. Somethings not right, especially with claims of sub 12L/100km around town.
If you are going off the trip computer I don't believe it, if you are checking fuel consumed and it is genuinely that, then there is genuinely something wrong with mine and it needs to be fixed.

I'd like a break down list of everything I can check to find out why its so crap. I'm not a car person so i'm not familiar with EFI systems and how to correctly check any sensors, injectors etc

edit: you say you have a different fuel map? so the stock ECU can be flashed and tuned for optimal fuel burn?

Ok, so first off the condition of paintwork and how clean your engine bay means jack if it hasn't been looked after.

Also, it doesn't matter if you baby it now, if the rings or seals are all shot from it being thrashed in the past there's not a whole lot you can do about it.

Yes the stock ECU can be flashed providing you have the hardware & software. Or someone that can do it.

A lot of the factors involved in good fuel economy are driving style (auto / manual are different), good air filter and plugs, good engine internals, and the condition of your CAT/o2 sensor.

Ok, so first off the condition of paintwork and how clean your engine bay means jack if it hasn't been looked after.

Nobody thrashes a car and then gets in with a toothbrush and cleans the engine bay on a weekly basis and polishes the entire car top to bottom
It was driven by a middle aged lady to work and back, that was about it. Everything was booked in for servicing at scheduled intervals

Air filter is new, plugs are only ~3000km old. O2 sensor is new

Anyway I found the section of the manual dealing with warm up temperature, it's under 'multipoint fuel injection' then way down the bottom. Coolant temperature sensor is removed from the car then immersed in hot water, measure resistance with a multimeter
0c - 5.1-6.5k
20c - 2.1-2.7k
40c - 0.9-1.3k
80 - 0.26-0.36k

Going to do that now

Nobody thrashes a car and then gets in with a toothbrush and cleans the engine bay on a weekly basis and polishes the entire car top to bottom
It was driven by a middle aged lady to work and back, that was about it. Everything was booked in for servicing at scheduled intervals

Air filter is new, plugs are only ~3000km old. O2 sensor is new

Anyway I found the section of the manual dealing with warm up temperature, it's under 'multipoint fuel injection' then way down the bottom. Coolant temperature sensor is removed from the car then immersed in hot water, measure resistance with a multimeter
0c - 5.1-6.5k
20c - 2.1-2.7k
40c - 0.9-1.3k
80 - 0.26-0.36k

Going to do that now

Thankyou, that finally answers the question regarding the condition then.

As mentioned, there are a few general maintenance items that need to be checked. Once those are out of the way you can start looking at more serious issues.

As mentioned, there are a few general maintenance items that need to be checked. Once those are out of the way you can start looking at more serious issues.

Thank you but could you list WHAT I need to check? i'm not a car person and don't fully understand EFI systems on cars

I checked the coolant sensor
at 26.8c (ambient temperature) it's showing 1.97k which is to be expected
at 81c it's 0.37k which again is to be expected, and it gets there quite quickly (about 5 seconds) so that sensor is fine.

Next?

Well that fuel injector cleaner wont do a hell of a lot, seriously, if you want them cleaned, get them taken out, ultra sonic cleaned, re-kitted, and re-fitted. When you cleaned the TB, did you take it off the car, stripped it down, carby cleaned the whole thing out, and replaced the 2 O ring seals, including the gasket in the water transfer? another thing, if i was to be able to get my car past the speed limiter to 220km/h i bet i would use a 1/4 of tank of fuel just trying to get there. sounds like everything else checks out

Could be the airflow meter. Or the wiring to the temp sensor or O2 sensor. Have you checked the ECU for fault codes. Would be good also to plug it into a laptop with evoscan and check that all the sensors operate correctly such as TPS, coolant temp, O2 and see what the airflow meter is doing.

my 00 TJ 4 spd 3.5L wagon gets around the 12-13L/100 kays in mixed driving and thats doing a lot of coasting and easy throttle in stop start driving conditions.

My car has done 215k kays and is ready for a major service (air/fuel filter, timing and ancillery belts, waterpump, crank/cam/valve/spark plug tube seals, spark plugs) but my old 97 verada with 320k kays consistently sat around 10-11L/100 kays and it was a POS...

The stock ECU of any F, H, J, L or W series Magna can definitely be reflashed, though what can be changed is more restricted in the H & J series (by limited information availability rather than the capability of the ECU). If you'd like to know a bit more, the thread linked in my signature may be of interest.

A friend suggested today that the timing belt might be out 1 tooth. He had similiar results in a different car and also lost about 200km to a tank when the timing belt was changed and not aligned correctly.

Possible in my situation?

I don't have first hand experience with this, but I'd suggest that there'd be other, more immediate signs if your belt had skipped a tooth, such as terrible idle or stalling, severely reduced power, etc. I could be wrong though, I've not seen this happen myself.

are u using the same servo or type of fuel? mabey your servo has a crap batch of fuel...


My sujestion would be to, drain out as much as u can.....go to a BP servo outside your area fill up a FULL tank of premium 98 octane and wack in a FULL 500mls of nulon fuel injector flush (over treatment does not harm anything)....disconnect your battery for an 1hr or so, then take your car for a drive on the freeway 90-100km/h for a solid 30mins no traffic and see if that helps your problem....light throttle low revs, and light throttle high revs 4,500rpm for 1min or so just to clean up the valves...then back to low revs and cruise...


That would be your cheapest option before you start pulling apart stuff not knowing what the problem is......

Then if it is still crap fuel economey.....Run a compression check if all is healthy.....

Change Spark Plugs
Remove and ultra sonic clean fuel injectors and rail
Change Fuel Injector Tips
Change Fuel Injector O Rings
Change Fuel Pump
Change Fuel Filter
Change fuel regulator or soleinoids (if there are any)
Flush Out fuel lines and check for leaks
Replace Air Filter
Clean MAF/MAP Sensor with CRC MAF Cleaner
Clean Throttle Body with Nulon Throttle body Cleaner
Clean all intake hoses
Check all vaccume hoses for leaks and cracks

If that does not fix your problem its the way you drive

Something is sucking fuel beyond your driving style in IMO.

I mentioned your AC before, have you tried setting it at 23, or even 22, and doing a tank full, or even half a tank and seeing if it changes?

Does seem weird if the economy is getting worse though.

My 3rd gen wagon has a 6g75 motor with custom cams (more power but more fuel consumption also) and it has never gone over 15l/100km, even with no highway driving at all.
I do give it the juice a lot, but not all the time.
I do have a manual which makes a big difference, but The main difference I see is perhaps Air Con?

I know they say you can't have a big car, plus great performance, plus good fuel economy but I reckon the magna is hard to beat.
My wife had a ss commodore wagon, 6 litre 6 speed with all the performance options ticked.
My magna wagon had more space (at least in the back part), I reckon it was faster (0-100 not sure as magna has traction issue, but around a track for sure), and the magna had 30% better fuel economy.

Dont take this the wrong way, because how you use your car is up to you and it is your right, but Do you have a friend with a similar magna where you could swap cars and both drive it as you would your own for a day or two.
So that is reset the air con and use similar driving habits etc. and then see results. Are they different?
This would tell you if it is your car or your habits maybe?

At least then you can say this car doesn't suit me.

Ill try a/c off. Ive recently noticed a 'ticking' noise but thougjt it was only when driven hard. Now it seems to be a lot more common so i reckon it needs a valve adjustment. Will post a vid in a new thread soon

ANy way to check fuel injectors before doing anything with them? Everything labor here is like 2-3x more expensive

I get 13.5 and knowing my driving style, unless you are on a drag strip every day its not at all possible to be your driving style! I know its a costly way, though sometimes the costly way is actually the cheaper one. Wouldnt connecting a computer along with an experienced Mitsubishi diagnostician probably be able to work it out?

well i found the tapping noise, lack of oil to the hydraulic lifters. Oil was below the dipstick. Didn't think the car would burn that much oil, it was changed about 3000-4000km ago
I imagine that would also drop fuel economy 'a bit' but nowhere near what i'm getting

What can I check with basic tools? Is there any use in pulling the fuel rail and injectors and looking at them?
Theories and such are good but I need some way to check things not just think about them. Fuel doesn't seem to make sense since I can push it to 220, i'd imagine any sort of injector issue wouldn't permit that, but then again nothing else makes sense either so I have to look somewhere

Best check your oil level every time you fill up.

Sounds like that engine is quite tired & worn, drive it like a granny and keep the revs down as much as you can. My TJ rarely sees 3,000 rpm in normal driving.

How many km on the engine? Not unusual for a worn 3.5 to lose compression and show increased fuel consumption as well as burning a lot of oil. It is a 16 year old car after all.

I'm sure the compression is down quite a bit because the previous owner drove it too soft. Engines - at least in terms of the combustion chambers - like a good flogging every now and then. Every engine i've rebuilt or had from new/near new has been run in hard and end up with very clean pistons and very little to no oil consumption. Of course at this point it's not relevant

Car has 160k on it and I use the power and take it through the revs. It doesn't blow any smoke whatsoever so it can't be that tired. There IS a small oil leak around what looks like the rear rocker cover. The gaskets were replaced not long ago (before I bought it) but i've heard this is still quite common. The fact there's maybe a drip or 2 on the ground where it's parked didn't give me any cause for alarm

Might want to get on the leak then. Thats a serious oil lost over such a short period. Id be surprised if it was all in the external leak.
Is getting a guy around from Petrojet or some service similar out of the question? Im guessing the problem is in their field. Worth giving them a call...

Car has 160k on it and I use the power and take it through the revs. It doesn't blow any smoke whatsoever so it can't be that tired.

Get someone to drive behind you when you do your driving to look for smoke. Impossible to see a trail of blue smoke from the driver's seat.

To go off the dipstick that quickly is a serious problem, unless you leave a trail of oil drips as you drive, it must be burning it.

i get around 11.8 driving to and from work suburban streets and hwy mixed about 2.9ltrs for 26klm driving in my 5 speed auto tj sports

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Get someone to drive behind you when you do your driving to look for smoke. Impossible to see a trail of blue smoke from the driver's seat.

To go off the dipstick that quickly is a serious problem, unless you leave a trail of oil drips as you drive, it must be burning it.

better to look for smoke at night with headlights behind you... my old 3ltr at 340,000klm used to do it at high revs.

You said oil gets eaten.....I have 380 6g75 with the oil problem like your describing...


switch to 5w-40.....the 40 is plenty for aus.....the lower first number you go with oil the better fuel econmey you will have....Ive used 5w-40 and 10w-40 same brand oil.....i get better fuel econmey with the 5w....i used a 15w-50 for a test one time and my fuel ecomeny was shocking....i have 190,000kms hammered engine and i use 5w-40 and after 2-3weeks of top ups it stays full for the next 5,000-10,000kms and no problems what so ever


I find when i change oil my car eats fresh oil for some reason....each week i will need to top up 500mls-750mls worth of oil for the first 2-3weeks, then after that no matter how i drive, and how many kms i punch down the oil stays full....its as if my motor just eats the fresh oil then after it doesnt eat it anymore....

What method are you using to calculate fuel economy? If you are using the cars readout try doing it by hand for a few tanks using pen, paper and a calculator and see if it lines up.

Does the KF have the instant readout for fuel usage and or the average fuel readout while driving. If it has the instant readout then try cruising at a constant speed on flat road at 70kph and see what fuel you get. If it has the average readout try going for a cruise on the freeway, just total cruise with no accelerating and see if the average drops.

Try driving for just 1 tank of fuel without hammering the car, try to drive like a granny, just to see if it's possible to improve your economy at all. If it doesn't then you will no for sure it's the car and not you.

Mine doesn't have a trip computer
I calculate how much fuel goes in and work off that

I have found that if I drive until the reserve light comes on and STAYS on on a perfectly level surface while moving, it's pretty damn consistent. I've always filled up at that point and it's always been 63.X litres. So i'm using that to do some runs with $50/31.2L in various combinations. At the moment i'm doing no aircon at all and limitted to 30% throttle. It doesn't look like i'm going to get much. I'm sitting on 180k's and it's not far off reserve, might be able to get 250 out of it which would equate to 12.5L which still seems like a LOT for driving like a grandpa, with no aircon, and windows up (yes it sucks)
BTW whoever said they rarely see 3k rpm, if you have a 4 speed you must be a grandpa. Even with 30% throttle it'll go to 3k rpm before shifting into 2nd or 3rd. And that is slow, at least 20 seconds from 0-100kph

Edit: Oil i'm using is penrite HRR 10 (10w50? 10w40? I believe it was the latter)

Fuel economy is not so much much about how little throttle you use but more about how little brake you use. Every time you use the brakes the cars kinectic engergy is being converted into heat, then you need power from the engine to replace this lost energy and get back up to speed. This can consume a lot of fuel. Try to drive without using the brakes (if safe of course), except to come to a complete stop when the vehicle speed is under 40km/h. Going from 100 down to 90 km/h takes away a lot more energy than going from 40 to 30km/h due to kinectic energy being a squared function. Twice the speed = 4 times the energy.

That's all well and good but I didn't buy a 3.5L car to have my head implode from boredom. I actually researched the fuel economy and was happy with the quoted figures on forums but i'm just not getting those figures, not even close. And thats my problem
It has to be bareable to drive and 'economy driving' is an utterly terrible experience. I can't believe there are forums of people dedicated to it.... but hey thats them

I'll see how this run goes cause its pretty much a best case scenario that I can't live with day to day, so if it does yield 12.5L then I can't do it. There's no way i'm driving around in Cairns with no aircon and no power, bottom line.
In which case i'll look very seriously at a VTEC prelude. That's about the only other car i'm interested in ATM as its still a nice comfy car to be in and drive day to day, but has some performance and reliability to it. I just wish the auto's weren't notoriously so unreliable... I think I can sacrifice a go to a manual

12.5 would be a reasonable city/country mix or standard suburban cruising from a car the size and age of the TF. It's a bit high but without knowing your usual route (how many traffic lights, hills, stop signs, railway crossings, etc. etc.) it's really not possible to gauge. If it's all highway with no overtaking, no speeding, no Fangio take-offs, AC off and windows up then yes, it's high. Under these conditions my TJ would be around the 8.0-8.5 mark. The way I see it, there's essentially three things that can destroy fuel economy aside from driving style:

1) The ECU or another component is acting on incorrect information, such as a dodgy sensor. If the MAF is on the way out it most likely won't be fixed with any amount of cleaner and will need replacing. You've checked the temp sensor but what about the wax pellet in the throttle body? Is the water channel clear and the baffle operating correctly? Is the air intake pipe airtight, no leaky manifold gaskets, PCV system clear and tight, fuel cap sealing, TPS correctly set, etc.?

2) Power is down so you're compensating by giving it more throttle. There's any number of things that can cause power to drop, including dodgy fuel, clogged fuel filter, bad fuel pressure regulator, rings on the way out, burnt valves, collapsing coil, burned out or worn dizzy cap or rotor, etc. etc. etc.

3) Excessive weight or drag to move the car. I think you already eliminated this but just in case, are any brakes dragging excessively or the handbrake not releasing fully? Tyres in good nick and to pressure? Wheel alignment within specs? Boot not full of bricks?

The only way to find the problem is to check each component in turn, the manual provides checking steps for most of these bits and pieces. It comes down to how much time do you want to spend? It could take a while to find and it could turn out to be expensive, but if it was, say, a leak in the air intake pipe (potentially 'fixed' temporarily with a bit of gaffer tape!) it'd be a whole lot cheaper than a Prelude. To be honest, it sounds like your heart's already set on the Honda, so finding the problem with the Magna just might not be worth your time.

BTW whoever said they rarely see 3k rpm, if you have a 4 speed you must be a grandpa. Even with 30% throttle it'll go to 3k rpm before shifting into 2nd or 3rd. And that is slow, at least 20 seconds from 0-100kph



That was me! Grandpa speed, 4 speed gearbox adapts to your driving style. First to second shift is at 2,200 to 2,500 rpm. Mine is on 14.3 L/100 km, due to nothing but short trips.

Mine sits in the mid 13's around town using 95 Ron, then if I chuck in a few hundred clicks of hwy driving i get mid 10's (3.5L TJ 4 spd wagon with 220k kays running valvoline 5w40 syn)

Thought i'd quickly pop out and grab new leads, distributor cap and rotor. I could have swore I saw them done on a prior servicing report by previous owner but I can't seem to find them so figured i'd do it anyway

Don't know why but I opened the bonnet and noticed some coolant on the radiator, must have been some splash from when I last changed it so I hosed it off, put the hose away, coolant there again. Ok it must be drained off from somewhere i'll throw a bucket of water on it, coolant still there. Look closely and....



http://i59.tinypic.com/2dw2he.jpg


May explain fuel economy problems?
The radiator was NOT cracked a week ago, it only cracked after changing fluid. Just had a shop check it out and they reckon the radiator is just old and brittle, and hoses are soft and swollen
They did a check for gases in the cooling system - none so head gasket is fine.

Been given a quote of $566 to replace radiator, thermostat, gaskets, hoses, clamps and full flush

May explain fuel economy problems?
Been given a quote of $566 to replace radiator, thermostat, gaskets, hoses, clamps and full flush[/QUOTE]

Nope, that won't affect fuel economy & is a common failure point. Shop around I'm pretty sure you can get denso radiators online. I get 11.5l per 100km highway cycle on a fully loaded AWD running LPG & approx 13.5 city cycle fully loaded.


Cheers

Nope, that won't affect fuel economy

Though would a thermostat? and the cracked radiator (aside from age) is a symptom rather than a cause

Parts on ebay come to about $300 (including radiator fluid and demineralised water) which is all i'd need
The shop did do good by checking for blown head gasket as well. So thinking i'd swing them some cash even if I do it myself

Just wondering if the extra cash is worth it considering they are then responsible if there's a problem again within the next year

If your thermostat is stuck open it could potentially lead to high fuel consumption as it'd take a lot longer for the car to get up to temperature, but this would be obvious by looking at your temp gauge (assuming it's working). Also, a stuck-open thermostat would not cause the radiator to split, that seems more like an age thing. Dunno, I guess get your cooling issues fixed and see how your fuel consumption goes then.

Are your spark plugs due for a change? My AWD has a 6G75 and is tuned for 98ron fuel and when I hammer it it slurps like an alcoholic at a free happy hour bar! Goes hard though and I expect it to drink. Cruising with the cruise control and it shows usage as low as 7l/100k on a flat section but goes up to 10l/100k at 100k's.

This is what I do and I have no problems at all (keep in mimd I have a reflashed ecu, 6G75. You mentioned you used BP fuel. It may have been moisture ridden. The way to fix that is, wait for it, mineral turpentine! Go to Bunnings and buy a bottle of Diggers Turps. One litre will do the trick but you can put in up to 4 litres if your car is standard tuned for 91ron fuel.
The turps disperses moisture in the fuel lines and filters and cleans injectors too. Don't believe me? Ask a diesel mechanic.


Seriously............... up to 18L/100km now which is no longer funny. Fuel consumption seems to only ever go up with every tank I put through it. I used to get closer to the 500km mark out of a tank around town with some highway (which still seems crap compared to what some people claim) now its under 400km. Yes I drive it hard and use a lot of the power a lot of the time, but when i'm cruising i'm cruising. And I often use the cruise control. This is not flat out around a track. I get up to 60/80/100 as quick as possible then cruise there. I shouldn't be getting such utter garbage from a FWD KF Ei

I have replaced O2 sensor, air filter, run injector cleaner through 3 times, upper engine cleaner. Checked for fuel smell in engine bay (there is none), replaced fuel cap. Tank holds pressure, if removing the cap takes ~3-5 seconds to normalize
Car does 220kph with some extra to give so cat wouldn't be overly blocked surely
Idles fine, runs fine, very smooth, no misfires no issues. Just crap fuel economy
Adjusted handbrake so there is no drag at all. Some drag in front wheels but I don't know whats 'normal'
Tires would be in balance, no shakes at any speed. Pressures 36psi. Doesn't pull to the side. Alignment not checked but they point in a forward direction so wouldn't explain a potential ~6L/100km difference

What is everything, and I mean everything that I can check that would cause economy issues, without necessarily making the car run rubbish. I want to get to the bottom of this
Could the injectors be stuffed? miniature blackhole in the tank? car stuck in some sort of a 'warm up' mode?

I would like to keep this car, i'd even like to make it better with some moderate performance mods, followed by a 6G75 swap. But at the moment i'm looking at ~$5000/year in fuel which could literally be halved with a smaller engine'd car that still puts out more power and acceleration

Ok bought new radiator, cap and hoses from Repco for $280 (on 2nd thought need to check the receipt, think they charged me for a thermostat they didn't have)

Took me about 3 hours to swap them over, at least an hour of that for the 4 clamps. Whoever put those clamps on there needs to be shot. I really should have bought some new ones, they're in good condition but utterly crap to install with a ridiculous amount of tension. Took a huge amount of swearing and silicone spray to finally get them and the hoses on. Screw down ones would have taken a couple minutes

Anyway I figure before I refill it I should check the thermostat. I would have bought a new one but nothing in stock so i'll check this one first. Pulled the cover off but it looks like its swollen and wedged in there really good. They should slide out quite easily right? How the heck do I get it out

Not done one on a 6G7x before but once you've removed the housing the thermostat should just lift out, no trick to it as far as I know. Possibly gunked in a bit, tried grabbing it with pliers and giving it a bit of a wriggle? Probably worth having a new one to replace it with before getting too violent though.

Ok bought new radiator, cap and hoses from Repco for $280 (on 2nd thought need to check the receipt, think they charged me for a thermostat they didn't have)

Took me about 3 hours to swap them over, at least an hour of that for the 4 clamps. Whoever put those clamps on there needs to be shot. I really should have bought some new ones, they're in good condition but utterly crap to install with a ridiculous amount of tension. Took a huge amount of swearing and silicone spray to finally get them and the hoses on. Screw down ones would have taken a couple minutes

Anyway I figure before I refill it I should check the thermostat. I would have bought a new one but nothing in stock so i'll check this one first. Pulled the cover off but it looks like its swollen and wedged in there really good. They should slide out quite easily right? How the heck do I get it out

http://www.colourbox.com/preview/4036346-888181-tools-collection-metal-adjustable-water-pliers.jpg

2 minute job

2 minute job in theory, in practice not always
I wanted to actually re-use the thermostat if it was fine so I gave it only as much force as to not bend anything, wouldn't budge even slightly

Did eventually get it to pop with a small flat screwdriver, hammer and gently tapping around the edges

Threw it in some water and slowly took it the boil, it didn't budge at all until about 95c and only just opened after 100c, enough to pass water but not fully open. Very likely contributed to the cracked radiator but would this be a cause of crap economy?

Anyway radiator is in. Going to leave the thermostat out for tomorrow as I need the car, and i'd rather run without one temporarily than risk further damage to the new radiator. I'll pick one up tomorrow and swap it

As for the test run without A/C and limitted power, I did use A/C for a total of about 10km, probably less so not a major contributor. But it's at 210km and the reserve light has come on and off a few times, it'll stay on within the next 10-20km. No point going any further as it will not make it to 250km and even that would be 12.5L/100km with about 20% highway 80% town. But i'm going with 225km which is about 14L/100km (should note the previous tank was 14 as well, with my normal driving style). A/C has made practically no difference to economy, nor has reducing power significantly. I wouldn't say I was grannying it but I didn't use more than 30% throttle. Most of the time i'd take off at your typical corolla driver pace

I'll swap the thermostat and do another test. If thats not it, replace distributor cap, rotor and leads?

It's possible to be crap fuel. I just had three tanks in a row where consumption was 11l/100 (I do a fair amount of freeway running) plus, in two different towns (twice in Moe, Safeway petrol in Warragul)

I filled up in Melbournetown today, at a 7Eleven (Former Mobil site) and it's down to the 8s reported. The trip computer matches fairly well to me with a pencil and paper.

It's been this way for a looooooooooong time so that would have been a lot of crap fuel. havn't had a single tank that gets what most people claim to be getting

Anyway put new thermostat in, bought some more intake and upper engine cleaner as well. Decided to pull the intake body and give it a better clean. Absolutely filthy! spark plugs looked ok though really white. Not sure if thats normal? slight bit of oil on the threads but the ceramic tip was white on all of them, not tan. Though they all looked the same

Intake ports were disgusting as hell. I normally work on bikes where they are spotless, if I see a slight bit of dust thats dirty and gets cleaned out. All intake ports were black with carbon and oil. Is this the emissions control crap? liable to affect fuel economy that much?
Anyway gave all the cylinders, intake ports and throttle body a squirt. Should have got in there with a brush but didn't have a suitable one at the time. Anyway reassembled, idles a bit better (though it was always pretty good).
Have noticed the A/C significantly colder, can have it at least 2-3c higher

I'll see how this goes. I checked hoses and no splits that I could see

Sounds like your PCV system is blocked. Magna manifolds and plenums are usually pretty black but it shouldn't be more than a thin, dry layer of sooty stuff. The cross pipe from the back to front valve cover often blocks, along with the baffles in the valve covers. Pull the PCV valve from the grommet and the inlet pipe from the intake duct, and try blowing through the inlet pipe. You should be able to blow air through the system if your PCV system is clear. If not, the hoses are available from dealers and the valve cover baffles can be cleared with a can of degreaser and a blast through with the garden hose (take them off the motor first!) or a soak in kero. New PCV valves are about $15 through Repco or $90+ OEM (kinda easy decision there).

If your PCV system is clear and your getting lots of oily crap through your TB it could indicate stuffed rings, which could go some way towards explaining your fuel use as you use more throttle to compensate for loss of power.

Also worth giving your TB more than a squirt, Madmagna has posted the definitive TB cleaning tutorial, well worth finding though a filthy TB usually manifests as bad idle. Can't hurt, possibly one or more vac ports are blocked which could cause all sorts of problems with things like fuel pressure regulation, EGR valve operation (if you have one), etc.

If your spark plugs are white in colour, then you have a lean fuel system, this could be the cause to your bad fuel economy. need to check for vac leaks, blocked injectors, blocked fuel filter, bad fuel pump

I'll give that a try. It just seems weird with this car because as you say, a really dirty throttle body should result in poor idle. Magna/Verada's are notorious for bad idle and all of them have a little tiny stumble/shake when idling. Considering that i'd say mine is one of the best, yeah its there but its not overly noticeable it's really quite faint.

And yes it was more than a thin layer, it was quite a lot of crud. I tried to get a photo but it was too dark and didn't show any definition

I'll run this half tank and discount the results as I would have lost a bit of fuel just getting it started after cleaning. Will probably remove and clean it with a brass dremel brush within the next few weeks
I'll check the PCV valve in the next couple days

If your spark plugs are white in colour, then you have a lean fuel system, this could be the cause to your bad fuel economy. need to check for vac leaks, blocked injectors, blocked fuel filter, bad fuel pump

How do I check them though? I can't find any video's on how to check if an injector is partially blocked, it's all "does the solenoid operate? then its fine"
Fuel filter, and fuel pump. Can it be checked with basic tools or do I need a pressure gauge connected to the rail?

I don't have any stumbles or apparent lack of power, so there's nothing obvious just by driving it. It'll happily accept full throttle to the rev limitter

for the fuel filter, the way i check it, is take it off, empty the fuel out of it, and give it a shake, see if it rattles, check the colour of the fuel that comes out of it, get a white piece of paper and shake the fuel filter over it and see whats on the paper. sounds like the fuel pump it fine if you can "red line" it. injectors are a little bit of a problem to check, usually as a rule they leak, like my problem currently now, early morning starts the car will splutter to a start. i was having a lean fuel system not long ago, gave me horrid fuel economy, found out it was my O2 sensor. i had replaced that 12 months ago, but with an after market cheapie, replaced it again with a genuine one, and no more lean fuel system. to check for vac leaks (do at your own risk) get some carby cleaner, with the engine cold spray a little bit on the vac lines with the engine running of course, spray a little bit at the bottom of you r injectors where they seal to the head, listen for a change in idle.

Having the same problem as you. Having magna wagon TJ 3.5 V6 and there used to be 9l/100km on the computer display when I bought the car. It seemed to me that the petrol is disappearing so qucik, so I reset the computer and now I am driving in the city having 18l-18,2l/100km and already drove more then 250km. Pretty sad fuel economy. Now I am looking forward to change fuel filter and as soon as possible spark plugs. Already checked PCV and no problems at all.

Ok i pulled the throttle body off. Did remove the front piece which holds all the sensors and throttle plate but didn't pull off all the sensors. Very black and not smooth, small chunks of carbon and oil residue inside the 6 pipes. Used a whole can of carb and intake cleaner on that and the intake pipes on the engine. Still some crap so got out the dremel and wire bit and cleaned it thoroughly. Did the same with the intakes on the engine and very thoroughly blasted all the particles out with an air compressor. Some would have fallen into the cylinders with open valves so removed all the plugs and kept on blasting both ways to clean as best as possible. After ensuring no more fine particles coming out i reassembled. Battery had been disconnected for at least 2 hours so ECU reset. Fired up easily and idled at 1200rpm. Normally idles at 800rpm and after an ecu reset its lower and idles rough. My guess is there was so much crud in there the idle circuit was compensating with more air to keep it running. After a couple short drives its still idling around 1100-1200 but smooth as butter. Will do the 'bypass and adjust' procedure in the next couple days

I then looked at the PCV. The pipe on the intake manifold is reasonably clean, the PCV side looked blocked and was dirty. But i could blow through it, though I can blow from both directions so I guess i should replace it?
What about cleaning the engine. should I remove the covers, hit it with more carb cleaner? Or just leave it and replace the PCV

Removing the covers can be problematic due to the rather delicate nature of the valve cover seals. The cover bolts must be torqued exactly (from memory its 3.5Nm but don't quote me) and few torque wrenches are calibrated low enough. Too little, covers leak. To much, covers warp and then leak. If they're leaking now (many do, down the back can be hard to spot) it's worth removing them for cleaning, replacing seals*, and re-torquing, but before doing that I'd do the whole-system blow through I mentioned in an earlier post (ie. remove the PCV valve and try to blow air (with your mouth) through the PCV inlet pipe which is the small diameter tube running from the rear cover to the main air intake duct just upstream of the throttle body). If you can blow air through with the PCV valve removed from the grommet (and the oil filler cap on) then your system's clear. With your finger over the grommet you shouldn't be able to blow through, if you can then there's a leak somewhere, ie. split hose, leaking oil cap, etc. If it's blocked it could be the hose from the back to the front valve cover full up with crap (happened on my TJ), and/or the baffles inside the covers themselves could be blocked (mine were). If replacing the hoses make sure you only use the correct type (available from dealers), normal heater hose won't handle the oil and fumes.

* Re seals, there's a couple of threads on here on this subject. The seal sits in a groove which may need to be adjusted if fitting a new seal. With the seal pressed in, you should be able to hold the cover seal-side-down and the seal should not fall out. If it does, you'll need to gently re-size the groove with pliers where the seal isn't being held in.

EDIT: PCV valve should act as a one-way valve under most conditions. If in doubt, replace it (about $15 from Repco).

Yes I can blow through the system. Didn't think to try checking for a leak though. And yes the rocker cover seals were replaced not long ago (by mitsubishi dealer) but yes the rear one still leaks. Chances are the covers are warped

I'm curious to see how fuel consumption goes now because I can definitely feel the engine is happier. I think I need to replace my leads as there is still an occasional hiccup when starting the car (one or 2 inefficient burns, then it starts)
But despite that, the engine is smoother than its ever been. It was never bad to begin with and a very smooth car, but its now even smoother. To the point where even under full throttle through the rev range there is no vibration. Anything above 1500rpm is unnoticeable aside from the sound. No extra power but definitely smoother response
I can also hold 60kph with less throttle, pretty much only have to rest my foot on the pedal. Though that could be because of the higher idle. Even so i'd say the higher idle is because it can flow easier, and ultimately - fingers crossed - good and expected fuel consumption

All sounds good, I guess it's a case of wait and see!

If your spark plugs are white in colour, then you have a lean fuel system, this could be the cause to your bad fuel economy. need to check for vac leaks, blocked injectors, blocked fuel filter, bad fuel pump

why would a car running "Lean" aka reduced fuel ratio cause the car to be more thirsty? cars can run leaner to get more power and efficiency but its not good for the engines due to higher temps and the reduced fuel lubrication

why would a car running "Lean" aka reduced fuel ratio cause the car to be more thirsty? cars can run leaner to get more power and efficiency but its not good for the engines due to higher temps and the reduced fuel lubrication

you didnt notice the word COULD in my comment did you?, im sure you did, you must have just over looked it

If its too lean it will be an inefficient burn and lose power, that will result in poor economy. I'm skeptical as to whether it actually is lean though. You need to pull the plugs at various rev ranges, i.e. run at x% throttle for a few seconds then kill the engine and immediately pull and check the plugs. Idling into a parking space and then check them will only show a rough A/F ratio at idle, not throughout the revs?

Not looking forward to checking the filter as thats pretty much impossible for me to do if I have to drain the tank. So i'll see how this goes in the meantime

Done a compression test yet?
From the amount of oil this engine uses, and the blowby it is showing, it may not be a simple fix. Are you sure the Km on the speedo readout is legitimate? They can "accidentally" lose 100,000 km, with a bit of help. Depends on the history of the car, really. I've walked away from dealer cars because the spotless engine bay and speedo reading didn't match with the wear on the driver's seat and pedal rubbers.

I believe this car was genuine, driven by a middle aged lady and wear n tear was pretty much non existent anywhere. Even getting underneath the car it was ridiculously clean. I don't have a compression tester, but thinking of grabbing a $30 ebay one

But that said, i'm of the impression she drove it to work and back (about 4km each way) and not much else. I also don't believe she had the revs up very much and baby'd it everywhere. Both of which aren't good for the combustion chamber and most certainly led to glazed cylinder walls

If my economy is still rubbish i'll get a compression tester and see how that goes. If there are problems with the cylinders i'll sit down and have a think as to whether to sell it, or throw a 6G75 in. No way i'm putting serious money into that engine when I can get a better one (i'm yet to hear of a single bad thing about the swap?). And it doesn't seem that difficult to do unless I need special tools? Engine hoist, couple guys, impact wrench and a weekend?

Had a mechanic hook up a scan tool and read it. Reported something about a cam sensor (cam position sensor?) but no apparent issues so cleared it and we'll see if it comes back later. Other than that, 3 messages to do with ignition/immobilizer but i've never had any problem there....

Will order a compression tester soon

Don't have a definitive result yet but its looking like this tank is going to yield yet another 400km, maybe 450 if i'm lucky

Anyway 2 things I decided to check
The first being an obvious yet overlooked one, is my trip meter accurate? Well I did a drive and compared it to the GPS, car showed 24.4km, GPS showed 23.7km so the car is being generous, its not that.
Compression tester arrived so thought i'd give that a go, at least on the front bank
Probably incorrect numbers but i'm going to assume that looking at the car from the bonnet, that the front bank on the right side (air intake side) is cylinder 6, middle is 4 and front left is 2

Dry readings came back as
Cyl 2 - 126psi
Cyl 4 - 130psi
Cyl 6 - 130psi

Wet readings were a bit... iffy. Cylinder 4 spiked to 180psi at one point (think I forgot to release the pressure), and even showed 150psi at one point, but tested it 2 more times and the readings came back as...
Cyl 2 - 135psi
Cyl 4 - 138psi
Cyl 6 - 135psi

Not sure how much I trust this tester, one of the o-rings already broke, and the pressure was not constant, it slowly but continuously dropped. Tried it on a motorbike which just recently had an top end rebuild (rebored) and it came back as close to 140psi both wet and dry, manual states 170psi but I havn't found anyone get that reading yet

Not sure if its been mentioned before but what about your O2 sensor?

Not sure if its been mentioned before but what about your O2 sensor?
Mightn't hurt to read the first post rather than just the title, since the OP has said that the O2 sensor has been replaced...

Mightn't hurt to read the first post rather than just the title, since the OP has said that the O2 sensor has been replaced...

:redface:

fuel economy actually dropped after replacing the O2 Sensor, makes me wish I didn't throw it in the bin and could refit it for testing. I know it was junk because the car was noticeably rich by smell, but if I put it back in and fuel economy went up well..... maybe the ECU is to blame?

Anyway I shall be revising the first post at a later day as more information becomes clear. If I ever do find the cause of this i'll be sure to put it on the front page along with everything I checked to get to that point

Right now I need to find some way to check the accuracy of this compression tester. 130psi is right on the lower service limit (890kpa = 129.08 psi), but it doesn't make sense that a wet test is only 138psi, surely it should be up near 170psi if rings were worn. A difference of 8 psi indicates to me that the rings are in almost perfect condition, and the compression tester is simply reading low

someone hand me a wall so I can bang my head against it

Thought I was starting to get somewhere, 460km this time but upon filling, more fuel went in. End result? still 14.0L/100km, getting absolutely nowhere with this....

Is the KF cursed? is there anything in later model's that SIGNIFICANTLY improved fuel economy?

someone hand me a wall so I can bang my head against it

Thought I was starting to get somewhere, 460km this time but upon filling, more fuel went in. End result? still 14.0L/100km, getting absolutely nowhere with this....

Is the KF cursed? is there anything in later model's that SIGNIFICANTLY improved fuel economy?


Could it be the gearbox torque lock up converter not working?

http://en.wikipedia.org/wiki/Torque_converter#Lock-up_torque_converters

I notice mine comes in at about 80km/hr after I've gotten to (about) that speed and ease off the pedal the revs drop by a couple of hundred (maybe about 400?) - the revs go up immediately if you touch the accelerator. Possibly causing the issue. More learned members than myself may know if that could be the cause of the fuel use issue? Not sure how this is controlled (ECU or separate transmission control unit).

Is the KF cursed?

Put the car in neutral, engine off, handbrake off, on flat ground. Push.
If it is difficult or impossible to get the car rolling, look for brake drag - lubricating the slide pins and cleaning out the brake calipers works wonders to free up brake drag.

fuel economy actually dropped after replacing the O2 Sensor, makes me wish I didn't throw it in the bin and could refit it for testing. I know it was junk because the car was noticeably rich by smell, but if I put it back in and fuel economy went up well..... maybe the ECU is to blame?

Anyway I shall be revising the first post at a later day as more information becomes clear. If I ever do find the cause of this i'll be sure to put it on the front page along with everything I checked to get to that point

Right now I need to find some way to check the accuracy of this compression tester. 130psi is right on the lower service limit (890kpa = 129.08 psi), but it doesn't make sense that a wet test is only 138psi, surely it should be up near 170psi if rings were worn. A difference of 8 psi indicates to me that the rings are in almost perfect condition, and the compression tester is simply reading low

I small difference in readings from a dry to wet compression test indicates worn valves. Burnt or worn valves would show up with a vacuum test gauge - google/youtube and ebay will get you sorted.

Did you use a genuine O2 sensor - not some other brand? I could be about to start a sh!tstorm but I hear those genuine oxygen sensors are the only way to go.... just be prepared to bite the pillow as the price is large.

Put the car in neutral, engine off, handbrake off, on flat ground. Push.
If it is difficult or impossible to get the car rolling, look for brake drag - lubricating the slide pins and cleaning out the brake calipers works wonders to free up brake drag.

Only seems as difficult as a 1.5 tonne vehicle, not unusually so. And will roll under its own weight fairly well. So nope its not that


Did you use a genuine O2 sensor - not some other brand? I could be about to start a sh!tstorm but I hear those genuine oxygen sensors are the only way to go.... just be prepared to bite the pillow as the price is large.

Got it from mitsfix

And do you mean a leak-down test?

Video (https://www.google.com.au/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&q=vacuum%20test%20gauge)

I'm at work, so I'm limited to what I can link to.

A vacuum test gauge is the old school version of an ECU scanner/reader. It'll give you a better idea of what going on. It wont give you all of the answers, or tell you exactly what's going on, but it'll reduce the amount of time or the number of guesses you make in diagnosing an engine issue.

I'm not suggesting that if you buy one it will magically solve your problem. I bring it up because your compression test results hint at worn valves or related issue, something (among a lot of issues) a vac' gauge will easily diagnose.

Ok had a shop do a quick compression test on just 1 cylinder, the one that showed 126psi. Theirs showed 190psi, so thats how reliable a super cheap ebay compression tester is. It's not lack of compression, at least not on the front 3 banks

Another shop suggested a dyno run at the cost of ~$200 to do a run and have a bit of a poke around checking readings and such.
Or clean injectors for $150. Yep labor is bloody expensive up here...

Anything else I can do before dropping money on a dyno, which isn't going to tell me anything except whether or not its making power and the fuel ratio's are fine

Blocked cat' converter? Partially blocked or collapsed - no rattles from there? Though, you'd notice this as the engine would be a reluctant to rev.

EGR isn't stuck open? PCV in good shape?

No obvious leaks around the injectors - all connections to/from the injectors are clean?

Coolant temp sensor is good - I think you checked that right?

AC bearing/clutch is functioning normally?

AC/PS Belts aren't over tight or misaligned? You'd probably hear that though....

You've had at the intake (front TB to cylinder head) checking for vacuum leaks? Not sure that would greatly affect economy, but still worth a look.

Have you checked the fuel pressure/volume is within spec'?

Worked your way along the fuel lines for a visual inspection - nothing restricted/leaking/cracked fuel lines. Pull the seat out and pop off the inspection cover to see nothing is out of shape in there.

Got cruise control? Try driving it around with that alone to see if there is any change. Use cruise control to get you up to speed - from 60 to 80 for example. Compare the instant fuel consumption reading to your manual acceleration tests.

I haven't read the previous posts so I could be recycling ideas. MAF is clean and tested correctly right? Sometimes my MAF is a PIA to reconnect - feels connected but isnt. All your electrical connections cleaned and checked? Does the car shift normally - as in, its not constantly stuck in a learning state where it shifts at higher RPM? Speed sensor/output shaft sensors all good?

These engines - mechanically - are pretty solid, I'd be looking for a sensor thats just not quite right - something telling the ECU to use additional fuel. Most of the external factors wouldnt add up to such an increase in fuel consumption without being more noticeable - unless its a combination of factors.

Blocked cat' converter? Partially blocked or collapsed - no rattles from there? Though, you'd notice this as the engine would be a reluctant to rev.

EGR isn't stuck open? PCV in good shape?

No obvious leaks around the injectors - all connections to/from the injectors are clean?

Coolant temp sensor is good - I think you checked that right?

AC bearing/clutch is functioning normally?

AC/PS Belts aren't over tight or misaligned? You'd probably hear that though....

You've had at the intake (front TB to cylinder head) checking for vacuum leaks? Not sure that would greatly affect economy, but still worth a look.

Have you checked the fuel pressure/volume is within spec'?

Worked your way along the fuel lines for a visual inspection - nothing restricted/leaking/cracked fuel lines. Pull the seat out and pop off the inspection cover to see nothing is out of shape in there.

Got cruise control? Try driving it around with that alone to see if there is any change. Use cruise control to get you up to speed - from 60 to 80 for example. Compare the instant fuel consumption reading to your manual acceleration tests.

I haven't read the previous posts so I could be recycling ideas. MAF is clean and tested correctly right? Sometimes my MAF is a PIA to reconnect - feels connected but isnt. All your electrical connections cleaned and checked? Does the car shift normally - as in, its not constantly stuck in a learning state where it shifts at higher RPM? Speed sensor/output shaft sensors all good?

These engines - mechanically - are pretty solid, I'd be looking for a sensor thats just not quite right - something telling the ECU to use additional fuel. Most of the external factors wouldnt add up to such an increase in fuel consumption without being more noticeable - unless its a combination of factors.

No problems getting to 220kph so I don't think its the cat, i've knocked it with my fist a few times, can't hear any debris in there

PCV valve is worn and can blow air both ways, which reminds me I need to replace it, will do now....

Had a good check for intake leaks, can't see anything

Nothing I can see with the injectors but I can only visually see the front rail. I can't smell any fuel fumes in the engine bay though. Aside from that I don't know how to check them further

Coolant temp sensor I checked, within spec

A/C works fine, kicks in and out correctly. Not sure on the belts but I can't imagine that being a problem, no I don't hear anything. will have a look, how do I know if tight is 'too tight'?

Havn't checked fuel pressure no, how do I check that?

Havn't gone looking over fuel lines, will need to get it on some ramps to do that. At this point in time thats what I suspect

Have tried both with and without cruise control. Doesn't seem to make any noticeable difference, the KF doesn't have a trip computer however so I don't have an instant readout, I just have to go off calculations on when I refill

MAF I have cleaned but havn't tested. It does run worse when I unplug it, other than that i'm not sure how to check it

Car shifts normally, doesn't get stuck or hung up in gears. It shifts from 1st to 2nd at just below 3000rpm, often i'll go way higher than that if i'm overtaking so thats pretty normal for its learned state. 2nd-3rd-4th lower than that when just taking it easy

I'd suggest plugging in a laptop and seeing what data can be collected with Evoscan... but, I dont know if thats possible with a TF, and, interpreting the data is out of my league anyway. Which raises an interesting point regarding the dynotune - and this needs to be confirmed - that the pre-TJ ECU's cannot be flashed/altered. So, IF this is true, a dynotune might only provide you with a pretty graph.

Once again, I could be extremely wrong, please dont take my word for it. Just research it.

I'm wondering if a MUTIII scanner might be of more use to you - see if its throwing a code?

Fuel pressure check requires a special tool + fittings.

MAF can be tested, as far as I'm aware, and the tests are outlined in the workshop manual. There are a few other tests that might at the very least eliminate any faulty parts - like the injectors - all in the manual again. Sorry I can puke out exact numbers or test procedures.

Belt tension? About 8mm of play up/down midpoint between the two pulleys -check that manual again as my words arent as helpful as the pictures. But, lets face it, I doubt this is your issue.

EGR? No locked open? I have no idea how this would play into effecting economy. Would probably rob noticeable power before you'd notice the poor economy.

PCV valve might mess with economy, but it wouldn't be dramatic by itself.

Have you checked the ignition timing? As far as I know you cannot adjust it, but if its out at idle then you may have a faulty distributor?

Does the car get hot, you know, overheat just putting around? Do the thermo fans run constantly?

No funky smells or smoke under hard acceleration? Have somebody follow on a few hard acceleration tests.... or tie somebody to your bootlid.

This is pretty sh!t fuel economy... if I thrash the bejeezus out of my AWD I might see 16.2. Something is pretty messed up to get 18's in a FWD. What I'm saying is that for it to be this bad the issue would show itself in other ways - emissions, overheating, death rattles/grinds/squeaks, weird smells and or smoke from places that shouldn't smoke etc.

Any chance you can give the car to your nanna for a week? Somebody who drives like your Nan' to see if its not the 5kg ankle weights you're wearing on your right foot? :P

Good luck with your quest for better economy. I have no knowledge of value for you.

I'd suggest plugging in a laptop and seeing what data can be collected with Evoscan... but, I dont know if thats possible with a TF, and, interpreting the data is out of my league anyway. Which raises an interesting point regarding the dynotune - and this needs to be confirmed - that the pre-TJ ECU's cannot be flashed/altered.
F series, even E series, ECUs should log just fine with Evoscan. If an Evoscan (or MUT-III) is available, the first thing to check is the fuel trims - they should be within +/- 10%; if they're worse than that there is a problem somewhere.

If the car has the 12 pin reflash connector on the bottom edge of the dash between the diagnostic port and the steering column, the ECU should be reflashable although there are no readily accessible ROM definition files (but that is a solvable problem). As far as I've been able to determine, reflashing support was a running change in the 1998 F series. More info on reflashing in the thread linked in my sig...

F series, even E series, ECUs should log just fine with Evoscan. If an Evoscan (or MUT-III) is available, the first thing to check is the fuel trims - they should be within +/- 10%; if they're worse than that there is a problem somewhere.

If the car has the 12 pin reflash connector on the bottom edge of the dash between the diagnostic port and the steering column, the ECU should be reflashable although there are no readily accessible ROM definition files (but that is a solvable problem). As far as I've been able to determine, reflashing support was a running change in the 1998 F series. More info on reflashing in the thread linked in my sig...

Thanks WytWun!

I'm wondering if a MUTIII scanner might be of more use to you - see if its throwing a code?

Did that, only code it threw was cam position sensor. That's because of the compression test
While not important to my fuel consumption, I did discover that if you don't disconnect the crank angle sensor before cranking the engine with no intake, no spark plugs and you had just sprayed upper engine cleaner through the cylinders. Then it ejects flammable liquid everywhere, and spark comes directly through the leads even without plugs attached. Might have had to deal with a little bit of err... external combustion. So, disconnect the crank angle sensor :)

Car doesn't get hot, temperature never seems to move off 1 below middle

Don't have a timing light to check ignition timing

No strange smells. Havn't done the WOT smoke check yet, is on my to-do list

Unless everyone on here drives their car slower than a scooter with the brakes jammed on, my foot isn't the problem. Yeah i've been known to go WOT through a few corners or off the lights, but I don't do it that often. And if I do its only to the speed limit then go straight into coasting mode. Most of the time its 'above average' acceleration but not thrashing the thing, and I stick to the speed limits. It doesn't seem to make a huge difference. I've only had the 18L/100km on one tank, normally its 14L. If I drive reallllllly slow - and yes genuinely slow, like everyone overtakes me kind of slow - then I get 12.5L. Both are still stupidly high for what is about 60% city, 40% highway

If the car has the 12 pin reflash connector on the bottom edge of the dash between the diagnostic port and the steering column, the ECU should be reflashable although there are no readily accessible ROM definition files (but that is a solvable problem). As far as I've been able to determine, reflashing support was a running change in the 1998 F series. More info on reflashing in the thread linked in my sig...

How obvious is it? I just had a look, I can see the ODB-II connector (it only has 2 wires connected to it?) and thats about it, nothing next to it. But i'm not exactly sure where I should be looking. Up high? down low?

Did that, only code it threw was cam position sensor. That's because of the compression test While not important to my fuel consumption, I did discover that if you don't disconnect the crank angle sensor before cranking the engine with no intake, no spark plugs and you had just sprayed upper engine cleaner through the cylinders. Then it ejects flammable liquid everywhere, and spark comes directly through the leads even without plugs attached. Might have had to deal with a little bit of err... external combustion. So, disconnect the crank angle sensor :) Car doesn't get hot, temperature never seems to move off 1 below middle Don't have a timing light to check ignition timing No strange smells. Havn't done the WOT smoke check yet, is on my to-do list Unless everyone on here drives their car slower than a scooter with the brakes jammed on, my foot isn't the problem. Yeah i've been known to go WOT through a few corners or off the lights, but I don't do it that often. And if I do its only to the speed limit then go straight into coasting mode. Most of the time its 'above average' acceleration but not thrashing the thing, and I stick to the speed limits. It doesn't seem to make a huge difference. I've only had the 18L/100km on one tank, normally its 14L. If I drive reallllllly slow - and yes genuinely slow, like everyone overtakes me kind of slow - then I get 12.5L. Both are still stupidly high for what is about 60% city, 40% highway

External combustion? Yeah, there's your problem right there, that combustion needs to be on the inside.

You got pics of your sparkplugs? Sometimes that can help in diagnosing things.

Just taking the piss about your lead foot. For future reference, keep the "220kmph" thing under your hat next time.

This car is completely stock right? You didn't recently change a timing belt, or exhaust, or fit a supercharger? How about the wheels, brakes and suspension, all stock? I'm not suggesting that fitting a set of nice 19" wheels will blow your economy out. But, if you had recently fitted "something" it might have not fitted quite right or made something else not fit. Check any recent mods out.

Long shot. Just thought I'd ask. If the car has been a gas guzzler from the get go then ignore that last part.

You don't weigh 900kg or something weird like that? Don't have 900kg of dead bodies in the boot? Seriously, the cars not pulling any additional weight around? There's a front windscreen in still, no super bee style home made rear spoilers or roof racks? Anything to blow the aerodynamics out?

Dumb questions, but I gotta ask.

Throttle position sensor set correctly? This is tricky, my rule of thumb is to never, EVER, touch that damn TPS. If you do though, use Evoscan and Wytwuns destructions - works a treat.

The TPS, if it were out of adjustment, would give some weird symptoms. It's my limited understanding that the TPS contains the idle position switch, which (if out of whack) could affect economy. The tests for the TPS are in the manual, and it's pretty simple and only requires a multimeter. If you're close to somebody with an evoscan cable I would test/check and adjust that way.

We're pretty much coming up with blanks now though, all the theories have been spoken for. If I were in your boat - and I was 100% sure all sensors were within spec - I'd consider swapping the ECU/BEM out. That's just my theory, don't go shelling out for that yet - test and confirm everything else is good.

There's a front windscreen in still, no super bee style home made rear spoilers or roof racks? Anything to blow the aerodynamics out?

Dumb questions, but I gotta ask.


Oh so I REMOVE the parachute after i've been to the drag strip?

But nope, the cars all stock except for 17" alloys

I do have a pic of the plugs which i'll dig up at some point. They all look the same, all have a little oil residue on the threads

Timing belt was changed before I bought the car, so its recent. Brakes i've put new set front and rear with bendix pads. Wheels are in good condition no wobble or shake. Springs have gotten a tad soft, but its not rocking about or flapping back n forth in the breeze or anything.

No bodies, just a few spare bits n pieces in the trunk.

TPS I didn't touch, but thats not to say it hasn't been fiddled with before I bought it. Don't have access to an evo scan tool... although.... hmm I might know someone who has a compatible scanner

How obvious is it? I just had a look, I can see the ODB-II connector (it only has 2 wires connected to it?) and thats about it, nothing next to it. But i'm not exactly sure where I should be looking. Up high? down low?
It is a rectangular white (usually) connector tucked in behind the bottom edge of the dash about half way between the steering column and centre console. If you run your hand along that edge with the fingers folded over to the inside of the dash moulding, you should be able to feel it if it is there.

The reflash connector, if present, will only have 1 or maybe 2 wires connected. The diagnostic connector will have at least 4 wires connected.

The earliest cars I so far know of with the reflash connector were built in mid-98 (June or July I think, possibly May).

This isnt really helpful to finding the OPs problem, but from a statement made about other peoples fuel economy, i made 3 pics of my fuel economy, did this just 2 hours ago, and in a full hours run. 1st pic is around town, 2nd pic is highway. on both occasions i reset the average fuel. what got me this fuel economy was replacing the injectors with new ones, replacing the coil, replacing the O2 sensor (genuine) and fine tuning the TPS, and fully cleaning the TB and replacing the O`rings. Skapper can vouch for everything, and he knows how i drive as well.

http://i61.tinypic.com/zmcy0g.jpg

http://i61.tinypic.com/dyuno5.jpg

I havn't touched the fuel side of things yet, nothing. So it might be there, just seems really strange that if it was fuel, I can still do wide open throttle for extended periods no problem.
The fuel filter, can it be gotten to and checked/cleaned/replaced without draining the tank?

And is there any way to check injectors? All the tests i've seen seem to be either it works or it doesn't. Obviously mine are all operating so thats ok, but is there a way to check if an injector is maybe substandard? only atomizing some, and dribbling the rest?

I havn't touched the fuel side of things yet, nothing. So it might be there, just seems really strange that if it was fuel, I can still do wide open throttle for extended periods no problem.
The fuel filter, can it be gotten to and checked/cleaned/replaced without draining the tank?

And is there any way to check injectors? All the tests i've seen seem to be either it works or it doesn't. Obviously mine are all operating so thats ok, but is there a way to check if an injector is maybe substandard? only atomizing some, and dribbling the rest?

The fuel filter is east to get to, its under the car, close to the runner board, rear passenger door, just undo the fuel cap, take out the filter, you will loose some fuel, like maybe a couple of hundred mill, just don't take the filter off with a full tank. the only sign my injectors gave was the car spluttered to a start each morning, but in some cases, a lot of people have had their injectors sonic cleaned and noticed a vars improvement, just with me it was $20 more to buy new. the coil i changed because the car was idling rough, and felt a little like a slug when hot in the first 1/4 of throttle. and since you bought an O2 sensor from mitsfix then that wont be a problem, i got mine from rock auto last year, and for some reason, somehow, it sent my car lean, and lacking in power, so i changed that for genuine just a couple of months ago, and haven't looked back.

If it was the fuel filter, it would 'run out of steam' under full throttle, but operate normally at low RPM or throttle. Check the fuel pressure, or check the injectors and get them cleaned.

I can still do wide open throttle for extended periods no problem.


WOT for extended periods?

And you can get it up to 220 KPH!

I still think your driving style is a big factor in the fuel consumption.

My TJ is sitting on 14.2 L/100 Km after a full tank, by the way. Grandpa driving, but short trips.

The V6 is a big lump and uses a lot of fuel warming up and won't give 2014 type fuel efficiency no matter what you do. Live with it or get a younger 4 cylinder & lighter car. Being smooth and reliable are more important to me than fuel efficiency anyway.

If it was the fuel filter, it would 'run out of steam' under full throttle, but operate normally at low RPM or throttle. Check the fuel pressure, or check the injectors and get them cleaned.

What's a typical cost? here I was quoted $25 each, so $150 a set. If it's significantly cheaper to send them off I can do that, as I have alternative transport and don't mind waiting a week or 2

Edit: or, a source to new injectors?

WOT for extended periods?

And you can get it up to 220 KPH!

I still think your driving style is a big factor in the fuel consumption.

My TJ is sitting on 14.2 L/100 Km after a full tank, by the way. Grandpa driving, but short trips.

The V6 is a big lump and uses a lot of fuel warming up and won't give 2014 type fuel efficiency no matter what you do. Live with it or get a younger 4 cylinder & lighter car. Being smooth and reliable are more important to me than fuel efficiency anyway.

Big cars with big motors being thrashed will always use lots of fuel, spending a fortune to save a few dollars in fuel makes no sense to me, this guy needs a suzuki swift something he can thrash and still wont cost him a fortune at the pump.

Big cars with big motors being thrashed will always use lots of fuel, spending a fortune to save a few dollars in fuel makes no sense to me, this guy needs a suzuki swift something he can thrash and still wont cost him a fortune at the pump.

In earlier posts I already said that driving incredibly sedately - to the point it pisses everyone off - uses 12.5L/100km. That is still WAY more than most on here are getting, and not typical usage. Something is wrong

If everyone else was getting those figures then sure, and I never would have bought the car in the first place. What if I picked up a suzuki swift and it too was using something insane like 12L/100km because something wasn't right, would you suggest I buy a scooter?

In earlier posts I already said that driving incredibly sedately - to the point it pisses everyone off - uses 12.5L/100km. That is still WAY more than most on here are getting, and not typical usage. Something is wrong

If everyone else was getting those figures then sure, and I never would have bought the car in the first place. What if I picked up a suzuki swift and it too was using something insane like 12L/100km because something wasn't right, would you suggest I buy a scooter?

Well true but 12.5 is pretty normal for one of these cars in suburban usage, my KH Verada averages 12.5 in a mix of city and country driving and thats driving pretty carefully. How many k's do you get out of a tank of fuel in your car just on highway cruising? I find these cars aren't as good on fuel as you would expect for a modern car, I have a CM Valiant 4.3 litre that only uses a bit more then my Verada does but I have 3 litre TF Magna that is pretty good on fuel, it gets about 750k's to a tank on the highway. If you want to drive one of these cars hard you would be lucky to get 16 litres per hundred k's, all I was saying is if you want to drive a car hard and get good economy you picked the wrong car buying a Magna, even if your Magna was perfectly tuned driving it hard your economy will suffer greatly.

- uses 12.5L/100km. That is still WAY more than most on here are getting, and not typical usage. Something is wrong


Checked my instantaneous fuel consumption today. From a cold start, it was on 60, then dropped off to 26 L/100 km after 1 km, then gradually went down.

After getting petrol, I reset the trip meter. With a hot engine and keeping within the 60 & 80 kph speed limit for the next 6 km, the average showed up as 11.5 L/100 km.

12.5L/100 km sounds fine.

I got 35L for $50 today, works out to 280 km or 18 cents per km if I'm averaging 12.5L/100 km. Of course, if I was in the car all day and every day, and did 1,000 km per week, I'd be up for $180 in petrol, and I'd be complaining too.

Dead easy to show low numbers though, reset the trip meter with a hot engine and do some steady 100 kph country driving, and it will show 7.3L/100 km.
If I photographed that, you would all be impressed, but it would hardly be an indication of the average over a full tank.

12.5L/100 km sounds fine.

The fuel economy thread says very different. Most people are claiming about 10L/100km with mixed driving. I get about 10.5L/100km on a long highway journey

The way I see it, i'm getting the economy of a twin turbo, without the power, or the noise

The fuel economy thread says very different. Most people are claiming about 10L/100km with mixed driving. I get about 10.5L/100km on a long highway journey

The way I see it, i'm getting the economy of a twin turbo, without the power, or the noise

OK, keep chasing possibilities for your terrible consumption figures.
I can see you giving up on the archaic Magna and getting the twin turbo for the power and noise, then complaining about the terrible fuel consumption. lol

Millenium,
To give you an idea I got 600+km from a tank in Canberra which equals roughly 10L/100km. Traffic in Canberra is low, and I would take longer routes to avoid areas with my traffic lights.

I have been driving the car in Sydney lately and average in the 12L/100km with limited to no highway driving.
This is with some heavy traffic, but never on weekday traffic.
If I was to drive this car in peak hour weekday traffic (say to work and back everyday) I think I would also be in the 16L range.

Have you had this on the dyno, just to see if the AFR is ok or not? At the least you will know if there is a problem or your expectations are too high

I agree that 12.5 is within specs for mixed city/highway, but I believe you mentioned this was your calculated fuel usage for purely highway (correct me if I'm wrong). I've gone back through all these posts to see if anything obvious has been missed, you mentioned at one point that you were going to leave the thermostat out. Just checking that a working thermostat has gone back in the car? If not, and you're running without a thermostat, your fuel consumption will be way higher than it should be since your engine will take forever to get up to temperature. It'd be like driving with the choke pulled all the way out, if anybody remembers what a choke is! My usage is basically the same as MadMax's, normal suburban peak-hour running sits about 12.5, highway around 8 to 8.5.

Your consumption does sound worse than it should be, and I don't believe it can all be driving style. My highway runs (commonly 1200km round trip) generally include at least 7 or 8 WOT overtaking manoeuvres (can't stand 105 in a 110 zone!) with cruise control on the rest of the time, a couple of passengers and often a fair bit of gear, and the best I've had was 7.8 (immediately after a TB clean, new MAF, dizzy, plugs, leads, filters, cleaned up plenum, etc.). Even towing a 4m tinny I managed less than 10, about 9.5 from memory.

I'm not sure what else to suggest that hasn't already been mentioned or eliminated. I'd be getting a pro onto the case, second only to putting up with the slightly crap economy it's probably your cheapest option.

Checked my instantaneous fuel consumption today. From a cold start, it was on 60, then dropped off to 26 L/100 km after 1 km, then gradually went down.

After getting petrol, I reset the trip meter. With a hot engine and keeping within the 60 & 80 kph speed limit for the next 6 km, the average showed up as 11.5 L/100 km.

12.5L/100 km sounds fine.


I got 35L for $50 today, works out to 280 km or 18 cents per km if I'm averaging 12.5L/100 km. Of course, if I was in the car all day and every day, and did 1,000 km per week, I'd be up for $180 in petrol, and I'd be complaining too.

Dead easy to show low numbers though, reset the trip meter with a hot engine and do some steady 100 kph country driving, and it will show 7.3L/100 km.
If I photographed that, you would all be impressed, but it would hardly be an indication of the average over a full tank.

your a twit madmax, i said you will need to ask skapper about my driving style, and obviously you didnt read my post, i wasent going to take a 1 hour video. you really need to engage your brain before you speak

Just checking that a working thermostat has gone back in the car? If not, and you're running without a thermostat, your fuel consumption will be way higher than it should be since your engine will take forever to get up to temperature. It'd be like driving with the choke pulled all the way out, if anybody remembers what a choke is! My usage is basically the same as MadMax's, normal suburban peak-hour running sits about 12.5, highway around 8 to 8.5.

Your consumption does sound worse than it should be, and I don't believe it can all be driving style. My highway runs (commonly 1200km round trip) generally include at least 7 or 8 WOT overtaking manoeuvres (can't stand 105 in a 110 zone!) with cruise control on the rest of the time, a couple of passengers and often a fair bit of gear, and the best I've had was 7.8 (immediately after a TB clean, new MAF, dizzy, plugs, leads, filters, cleaned up plenum, etc.). Even towing a 4m tinny I managed less than 10, about 9.5 from memory.

I'm not sure what else to suggest that hasn't already been mentioned or eliminated. I'd be getting a pro onto the case, second only to putting up with the slightly crap economy it's probably your cheapest option.

Yep new thermostat is in. My long journey highway style is about the same as yours, cruise control on, overtake silly people who can't do the speed limit. It's still about 10.5L which is significantly higher than almost everyone on here
Around town it is NOT 12.5L. That is purely a 'best case scenario' test where it was so god damn annoying to do that I would never, ever drive that way normally. It was embarassing being outdone by scooters and having lines of traffic behind me. 'Normal' usage is 14 for me, that would include less city traffic than many people I presume. Traffic here is nowhere near as bad as the big cities

You're a twit Madmax

Corrected for punctuation and spelling. lol

I have to confess though, that the Magnas seem to vary a lot in their fuel consumption. On the one trip where my TJ sedan gets 7.2L/100 km, my TL wagon does 10.2, and both are 4 speed autos. Can't attribute all of that to the differences in body shape. Has Mitsu made lots of running changes in compression, camshaft profiles and ECU tuning between different years on the 3.5L I don't know about?

Hmm, that's a difficult comparison to make. I assume the wagon is a bit heavier as well as being less aerodynamic, and above about 80kph wind resistance is usually the biggest drag factor on any car, all other things being equal. And that's the thing: are all other things equal with your TJ and TL? Are they running the same or similar tyres, same fuel, were both trips made in the same temperature and wind conditions, similar occupants and gear on board, etc.? I'm with you on the variance though, there seems to be a wide range of figures being quoted by different members, which I guess is fairly understandable since no two drivers drive in the same way for the same purpose and no two cars have the identical history. How they were run in when new could have an impact on economy for the rest of the engine's running lifetime. It also seems to me that the 6G7x engines, while fairly bulletproof overall, are sensitive to relatively small maladjustments or minor failures and this will show up as bad economy, among other things. It takes a lot to kill one, but not much to push it off optimal running. I don't think this is a weakness or even very unusual, the old Holden red motor was reknowned for continuing to run even when mostly cactus but who ever monitored economy on one (or cared over much)?

I can't imagine different drivers playing that much of a role though. I mean sure it will if one barely has a heartbeat and the other is on speed. But I literally cannot get some of the claimed figures no matter how hard I try. 10L around town? not in my wildest dreams, no matter what I do. Unless I get out and push it

I'm seriously thinking of a 6G75 swap, but if the problem lies with my fuel system, ECU, or any one of the sensors then I won't get any difference. If it is engine design or a worn engine, then I should immediately get a massive improvement in economy

But speaking of tyres, thats a good point. I have 235/45-17's. Stock ones are much narrower, Could that play a significant role?

Tyre size and compound would have an impact; very wide, soft, sticky tyres will have greater rolling resistance than narrow, hard tyres. I wouldn't have thought the difference would be major but I could be wrong about that, particularly if the wheel alignment was a bit out. Any chance of borrowing or buying cheap a set of standard rims and tyres to run a test, assuming you don't still have the originals?

As you say, swapping the engine MIGHT fix the problem but if it is in a peripheral sensor or the fuel system then you've blown your dough with nothing to show for it. I'd definitely get the problem diagnosed before spending that sort of money.

Is it worth grabbing these instead of getting the originals cleaned? Cost is about the same vs clean and rebuild with new seals http://m.ebay.com.au/itm/191117099131?nav=SEARCH
Im thinking no, since they're about $200 each elsewhere, surely $1000 difference accounts for something. And all of mine still function, though maybe not at their best

Is it worth grabbing these instead of getting the originals cleaned? Cost is about the same vs clean and rebuild with new seals http://m.ebay.com.au/itm/191117099131?nav=SEARCH
Im thinking no, since they're about $200 each elsewhere, surely $1000 difference accounts for something. And all of mine still function, though maybe not at their best

yep thats where i got mine, have had no troubles with them

I have to confess though, that the Magnas seem to vary a lot in their fuel consumption. On the one trip where my TJ sedan gets 7.2L/100 km, my TL wagon does 10.2, and both are 4 speed autos.

My 3.5L TH Wagon best was 7.3L/100 Highway but it did have slightly wider tyres on Mag wheels which will make a little more drag, my new(er) TJ Sports Wagon has 163Kw engine + the body kit and Jumbo rear wing which I expect makes for more drag and it gets to 7.5L/100 but only AFTER fixing a mis timed cam - before that the best was 8.9L/100 or more.

Millenium, if your car is using more petrol than it should it means it should be running rich. Have you had it on the dyno to check air:fuel ratios?

To be honest it seems like you are spending money trying to fix the issue yourself but maybe it would save you time/money/heartache if you just paid a competent mechanic to figure it out?

Millenium, if your car is using more petrol than it should it means it should be running rich. Have you had it on the dyno to check air:fuel ratios?

To be honest it seems like you are spending money trying to fix the issue yourself but maybe it would save you time/money/heartache if you just paid a competent mechanic to figure it out?

The problem is I don't know of any 'competent' mechanics up here. Diagnosing this sort of thing really needs a referral
Most of the mechanics here just say "14L/100km? yep, its a V6, thats normal"

A dyno run will cost $200, thats a lot of coin for something that won't solve anything. Say it does show rich. Well i'm still without any clue as to what's causing it

A dyno run will cost $200, thats a lot of coin for something that won't solve anything. Say it does show rich. Well i'm still without any clue as to what's causing it

Just looking at your spark plugs will tell you if it is running rich. Comparing rear to front bank will also tell you if there is a possible problem, like cam timing out on one bank. This can also be checked by removing the top covers and lining the crank marks up and seeing if the cam marks line up as well.

The problem is I don't know of any 'competent' mechanics up here. Diagnosing this sort of thing really needs a referral
Most of the mechanics here just say "14L/100km? yep, its a V6, thats normal"

A dyno run will cost $200, thats a lot of coin for something that won't solve anything. Say it does show rich. Well i'm still without any clue as to what's causing it

Say it shows that it's running normal though?

Say it shows that it's running normal though?

Then i'm in the exact same spot I currently am. And I absolutely refuse to believe that 14L/100km is 'normal'. Thats utter crap

Then i'm in the exact same spot I currently am. And I absolutely refuse to believe that 14L/100km is 'normal'. Thats utter crap

My KH Verada is averaging 13L/100km mix of highway and around town, and i drive it steady, if I drove it a bit hard I'm sure it would average 14L/100 k's no problems. Don't go spending a fortune to try and save a few dollars on fuel defeats the purpose, just sell the thing and buy something more economical.

Then there's also something wrong with yours

I understand people lie when it comes to economy, often not mentioning that they drive like there's a bomb sitting under the throttle waiting to go off at the tiniest touch. But even if they do drive slow as buggery, I can't come even remotely close to matching it no matter how steady I take it. So either somethings wrong, or there's something significantly different between the cars
13L vs 14L is an acceptable variation, but 10L or less vs 14L is not

I find that my TJ (4sp auto w/full ralliart kit and rims) uses between 4.3 and 5 litres an hour. This translates to :
17.2 - 20l/100 @ av 25km/h (shocking peak hour)
11.6 - 13.5l/100 @ av 37km/h (average run)
8.6 - 10l/100 @ av 50Km/h (good runs)

higher average speeds for me are usually long distance and include a higher portion of speeds in the 100-110km/h range.

little off topic but my LPG consumptions are always +22% (yet lpg is 60% cost of PULP, so fuel cost is ~75% of petrol)

It appears you have tried every "reasonable" step to cure your economy. (Reasonable meaning without spending a lot of cash, or barking your knuckles stripping the motor.)

You have replaced O2 sensor, so that discounts that. Short of looking at timing misalignment, injectors, leaky valves and a hundred other internal components, your options are limited.

Have you tried a replacement ECU? (fairly cheap, but I believe you need to get the keys and lock barrel with it)
It may just be your ecu has sh*t something internally, and doesn't have a trim circuit or something working properly anymore.

Another simple one would be the rotor button...as you stated your vehicle has more km than the space shuttle, it may be worn.

Just trying to be helpful.

My TJ has done 20 km in 3 trips since getting fuel, it is now sitting on 14.7 L/100 Km.

Meh - couldn't care less. It will get better in warmer weather and/or longer trips.

For now i'm giving up and getting back on the bike instead, way more power, way better economy, way more fun.

I would agree with the 'get another car' statements IF that were realistically possible. By realistic I mean not a massive downgrade, because everyone wants a small 4 cylinder, So they're all either expensive, or crappy. A $4500 verada is about a billion times better to be in and drive than a $4500 small car with its god awful interior, crappy ride, wind noise, road noise etc. So I could spend $12,000 on something nice but then that really does defeat the entire purpose of saving money on fuel

A random thought - are you measuring the fuel economy by filling at the pump and working out the consumption, or off the trip computer? - Could be that the Trip computer is either malfunctioning or being fed bad information from the engine ECU

KF's don't have a trip computer. I seem to mention this every 2nd page but thats ok I don't expect everyone to read every post.
So no, thats not an issue, I am working it out manually. Even if I was completely and utterly wrong in my calculations, the trip meter is reset every tank and it very rarely goes above 400km
Last tank was about 375km to reserve, pathetic

Yes I drive it hard and use a lot of the power a lot of the time, but when i'm cruising i'm cruising...

Car does 220kph with some extra to give
OK, so you thrash your car and expect good fuel economy. Reality check required.

Somehow I doubt that "220kph with some extra to give" claim. Especially from a basically stock 1998 Automatic Verada. 220kph on the speedo only means you've got a grossly optomistic speedo. Given the stock manual's top speed of ~190kph, getting to 220kph would require 55% more power (power required goes up as the cube of the speed increase) than even a manual delivers at the wheels.


I'm sure the compression is down quite a bit because the previous owner drove it too soft.
...
Car has 160k on it and I use the power and take it through the revs
Moderate driving won't reduce compression and, if it had done so, you'd be unable to reach the std top speed let alone your supposed 200kph. More evidence that your driving style is a major issue.


I calculate how much fuel goes in and work off that

I have found that if I drive until the reserve light comes on and STAYS on on a perfectly level surface while moving, it's pretty damn consistent. I've always filled up at that point and it's always been 63.X litres. So i'm using that to do some runs with $50/31.2L in various combinations
63 litres before reserve seems high. On mine, it's anywhere from 46 to 52 litres. It used to be around 56 litres, before dropping to the current range. The same behaviour could be affecting yours. Without a trip computer, the only reliable way of working out your fuel economy is to completely refill the tank each time and use a calculator to work out the consumption, based on the actual kms travelled & fuel used. unless you're actually measuring & calculating this way, all your worry might be over nothing more than a dodgy fuel level sensor (that and your driving style).


I can still do wide open throttle for extended periods no problem.
Did I mention that your driving style might be a contributing factor?


'Normal' usage is 14 for me, that would include less city traffic than many people I presume. Traffic here is nowhere near as bad as the big cities
Lots of short runs and hard driving will soon see your consumption skyrocket. The fact you have less traffic helps, but even in Canberra, its no worse than Cairns and I've seen 14km/l as an average when I was doing mainly 3-4km trips, and that's without driving anything like what you claim to do. At other times, it's been around 12.5km/l around town, when most of the trips were round-trips of 20+km without the engine having time to completely cool down in between.


I can't imagine different drivers playing that much of a role though.
It can make a huge difference. Given what you've said repeatedly about your driving style, I imagine most users here would get better fuel economy from your car than you do.


I absolutely refuse to believe that 14L/100km is 'normal'. Thats utter crap
What is normal for you may not be normal for anyone else. It all comes down to how the car is being used.


A dyno run will cost $200, thats a lot of coin for something that won't solve anything
That's way too much. When I replaced my Magna's headers the before & after comparison dyno checks cost $50 per session. Perhaps the $200 is for a dyno tune. In any event, dyno runs can be used to test your AFR. They'll also tell you how much power your car really produces, so you can compare it to all the Magnas & Veradas that can't do even 200km/h.

OK, so you thrash your car and expect good fuel economy. Reality check required.

I'm going to ignore quoting the rest of the post, as selective quoting is silly and does nothing but create a shit storm.

The thread title is not "sick of this crap fuel economy around a race track". The 220kph remark is to simply point out that the car is performing just fine. If it was fuel starvation it would never have got even close to that. If the engine was completely toast it likely also wouldn't get close to that. 220 is indicated on the dash, and yes it still had more pull in it. By GPS it would have indeed been closer to 190-200
I've already said numerous times that I don't simply thrash the car. And I have done 'economy runs' to check absolute best case scenario and it is still 12.5L. Not 'drive like everyone else' pseudo-slow, more like 'hold everybody up, everyone overtakes me including scooters, i want to kill myself from boredom' kind of slow. Even that is GARBAGE economy, and i'm never going to drive like that normally

My TJ has done 20 km in 3 trips since getting fuel, it is now sitting on 14.7 L/100 Km.

Meh - couldn't care less. It will get better in warmer weather and/or longer trips.

Mine runs consitently at 14.5 L/100 accross the whole tank. If I drive sedately, it gets as low as 13.8, or hard driving it rolls around 14.9.

All driving is in 50/60k zones and traffic. Never goes on a highway.

When I drive to country 250 km's once a year, it averages 8.5 l/100.

Clearly I sit in too much traffic.

I guess most people will now understand why Mitsu went for a much smaller fly-by-wire 4 cylinder MIVEC engine in most of it's Australian range. The engine works in its most efficient range over a much wider power band and has to work harder around town, so the town & open road consumptions are much better and closer together. A huge lump of a v6 which takes ages to warm up in comparison, then eases around town at 2 to 3 thousand rpm is hardly working at its most efficient. 110 KPH on the open road = efficient combustion, 7.7 L/100 km for me, around town = poor efficiency = double the fuel guzzling.
Meh. Still better than my 202 Holden HX . . . lol

OK, so you thrash your car and expect good fuel economy. Reality check required.

Somehow I doubt that "220kph with some extra to give" claim. Especially from a basically stock 1998 Automatic Verada. 220kph on the speedo only means you've got a grossly optomistic speedo. Given the stock manual's top speed of ~190kph, getting to 220kph would require 55% more power (power required goes up as the cube of the speed increase) than even a manual delivers at the wheels.


Moderate driving won't reduce compression and, if it had done so, you'd be unable to reach the std top speed let alone your supposed 200kph. More evidence that your driving style is a major issue.


63 litres before reserve seems high. On mine, it's anywhere from 46 to 52 litres. It used to be around 56 litres, before dropping to the current range. The same behaviour could be affecting yours. Without a trip computer, the only reliable way of working out your fuel economy is to completely refill the tank each time and use a calculator to work out the consumption, based on the actual kms travelled & fuel used. unless you're actually measuring & calculating this way, all your worry might be over nothing more than a dodgy fuel level sensor (that and your driving style).


Did I mention that your driving style might be a contributing factor?


Lots of short runs and hard driving will soon see your consumption skyrocket. The fact you have less traffic helps, but even in Canberra, its no worse than Cairns and I've seen 14km/l as an average when I was doing mainly 3-4km trips, and that's without driving anything like what you claim to do. At other times, it's been around 12.5km/l around town, when most of the trips were round-trips of 20+km without the engine having time to completely cool down in between.


It can make a huge difference. Given what you've said repeatedly about your driving style, I imagine most users here would get better fuel economy from your car than you do.


What is normal for you may not be normal for anyone else. It all comes down to how the car is being used.


That's way too much. When I replaced my Magna's headers the before & after comparison dyno checks cost $50 per session. Perhaps the $200 is for a dyno tune. In any event, dyno runs can be used to test your AFR. They'll also tell you how much power your car really produces, so you can compare it to all the Magnas & Veradas that can't do even 200km/h.

Yea I wouldn't worry about replying to him macro. I knew he was full of it when I saw his first few posts, claiming to do things that my fresh manual 3.5 couldn't.

It really turned me off of trying to help out when I couldn't even trust the source of where the info was coming from.

Cars get bad fuel economy when you've thrashed them, welcome to the real world.

Yea I wouldn't worry about replying to him macro. I knew he was full of it when I saw his first few posts, claiming to do things that my fresh manual 3.5 couldn't.

It really turned me off of trying to help out when I couldn't even trust the source of where the info was coming from.

Cars get bad fuel economy when you've thrashed them, welcome to the real world.

I try and include as much useful information as possible, and word it in such a way that anyone reading it thoroughly can get a better idea of whats going on than just "me cars not runnin right m8"

So if you did actually read some of my posts you would see that the car was driven by a middle aged lady who babied the thing and had it washed and waxed religiously. Not a scratch on the paintwork, engine bay clean as a whistle, everything smooth as silk. Looked like her husband was forced in there to clean it with a toothbrush. Even the underside of the car was crazy clean. People clean and polish cars to make them look a bit better when they sell. They don't give it a new paint job, new plastics, scrub the underside of the car etc. Not for a sub $5000 car
Full service history, everything done on time and all that jazz. I kind of believe it wasn't drifting and doing donuts its whole life....

So if you want to call it 'thrashed' its only been so for a few thousand K's. Not enough to cause a huge drop in economy. What is thrashed anyway? using more than 30% throttle and taking the engine through its rev range? wow.... you wouldn't like to see what i've done with my bikes then. They all receive a spiritted break-in and routinely use all of their available power. Yet the combustion chambers remain in fantastic condition with very high compression and little to no wear on the piston skirts and cylinder walls, go figure
And again - like I keep saying - i've done economy runs. Still utter, utter crap fuel economy.
Doing 220kph is actually a valid test, as valid as a dyno run. Clearly if it struggled to break 180kph there'd be something majorly wrong with the power output and could very well explain the lack of economy. I.e. brakes stuck on, worn combustion chamber etc.
If you can't do it thats not my problem, my car will and has as indicated by the speedo. GPS would be 190-200

In any case, i'm not bothering with the car anymore. I've switched over to a bike for around town. Way more power, 4.7L/100km around town when ridden as hard as possible, heaps more fun

The only crap is all your bs about doing 220kph on public roads for extended periods and still expecting decent fuel economy. Do you even own a GPS?

If you think 14l/100km is bad, just be thankful you weren't paying on the day my Magna did almost 30l/100km on one tankful... all on the highway and I never got over 100km/h.

The only crap is all your bs about doing 220kph on public roads for extended periods and still expecting decent fuel economy. Do you even own a GPS?

If you think 14l/100km is bad, just be thankful you weren't paying on the day my Magna did almost 30l/100km on one tankful... all on the highway and I never got over 100km/h.

/facepalm. Seriously? it's called context

So because I mention 220kph at one point or another, and then I mention fuel economy, they somehow in your mind end up in the same sentence?
Separate occasions, nothing to do with each other!

No point going any further with this as I might accidently mention something like airplane, oh crap now i've done it. Yes guys my fuel consumption is high because i've been racing airplanes at 220kph.... :nuts:

Please kill this thread....14 pages too many already.

if your interested in putting the pedal to the medal as you claim you dont have the mentality to talk about fuel consumption. maybe we can discuss this in 10years when you realise your driving habits have changed dramatically. A simple issue to fix your fuel consumption. Ill put $10 on you couldnt do a full tank of gas without reving the car over 3000rpm once. If you do you will get over 600kms to the tank and have good fuel consumption. 220kmh = 6000rpm = 18L per 100.

This thread is just getting silly so im closing it....... Just because i can.:)



P.S. if fuel consumption isnt getting better sell up and buy and LPG Nissan Micra.. No joke, it exists. Google it.

Sorry, you have had the car up to 220, I guess you have a long driveway as I am sure you would not be stupid enough on a public forum to brag about doing speeds like that on public roads, astounds me how many private roads seem to be cropping up around the place

How about trying to drive the car normally and you may find your economy goes back to normal