Hi all,

Just wanting a quick list of what to check if you've got a rough idle.

I've currently got quite a rough idle on both lpg and petrol. The engine shakes a fair bit and you can the vibrations through the cabin. It occurs most when the engine is cold.

My list of things to check is:
- Dirty Throttle body and/or ISC
- Faulty ISC
- Misadjusted TPS and/or ISC
- Broken engine mount(s)

What else needs to be checked/replaced?

I've thoroughly cleaned my throttle body and idle controller. I removed these and cleaned them with a good dose of carby cleaner. Throttle body was cleaned a few months ago but the ISC wasn't. They are both clean now as I meticulously cleaned them out in every nook and cranny. The idle roughness improved but it is not gone. Still can feel some vibrations when the car is idling.

I removed and readjusted the TPS according to the max ellery manual. This was done with a continuity function on a multimeter. Basically I inserted a 10cent coin between the tb levers and turned the TPS anti-clockwise until it I got continuity, then I turned the tps back a very slight knoch to the point before continuity (basically when the reading is NOT 1)

The car did go through a home diy manual conversion and the engine was left hanging off one mount with a jack underneath (no engine crane used) . The gearbox bracket on the firewall side of the gearbox did hit against the engine mount slightly and the top gearbox mount was manhandled a bit with a prybar. I've inspected all my engine mounts and visually I cannot find a tear/crack etc. The engine side gearbox mount is hard to see but I could not find a tear nor on any of the other engine mounts around the car.

Any ideas/suggestions of what to look for?

Thanks heaps folks!
- TheKovac

As it's rough on both LPG and petrol I'd be looking at ignition first. Plug leads usually leak and short out mostly when the engine is cold, so I'd ckeck them...make sure they are fully pushed onto the plugs and also at the distributer cap end. I'd also inspect any cables that may have gotten squashed or stretched when the engine was hanging.

rough idle hot and cold, pity you didn't mention what the tacho is doing at the same time.

As it's rough on both LPG and petrol I'd be looking at ignition first. Plug leads usually leak and short out mostly when the engine is cold, so I'd ckeck them...make sure they are fully pushed onto the plugs and also at the distributer cap end. I'd also inspect any cables that may have gotten squashed or stretched when the engine was hanging.

Thanks!

I never thought of the ignition system being the problem - I'll poke my head around and look into it. The engine harness was removed but to my knowledge the dizzy cap was untouched. Maybe we knocked out one of the leads when we were mucking around trying to get the gearbox lined up to the engine. I know we tapped the thermostat housing a few times and the dizzy is near by. Maybe the dizzy was knocked out of alignment? I'm trying to sus it out but I also seem to have a consistent high pitched "hissing" noise (like its on a cycle) - could that be a piston not getting a spark?

I might have to remove the dizzy and inspect it. I've just got first got to work out how to retune/readjust a dizzy if it gets removed.


rough idle hot and cold, pity you didn't mention what the tacho is doing at the same time.

RPM's are steady at around 900rpm. After the conversion and before I cleaned the TB & ISC they fluctuated a bit. Petrol was around 1100rpm and lpg was 600rpm. Idle speed has settled but vibrations have not.

i had a rough idle on mine after it was converted to lpg.... ends up that the intake manifold had an air leak where the upper meets the lower half.... lpg installer stripped the threads in two of the front bolt holes when installing a totally unnecessary spacer to the solenoid bracket so it would clear the injectors.... removed the spacer, re-tapped the holes, sourced some longer bolts, and now she's all good.

Interesting.

Ash are you talking about the lower part of the intake plenum that meets the engine? or the metal pipe that comes out the back of the intake plenum (near the firewall)?

I did remove the intake plenum to get access to the solenoid attached off one of the brake line mouts on the firewall, but I reattached the same way I always do. Never had much problems with idle. I'll reinspect the intake system for a vacuum leak somewhere.

Might be able get up a video tomorrow to show the noise and vibrations.

Might be worthwhile to inspect/replace the spark plugs and leads. They can sometimes cause the car to run a bit rough. The ignition leads might have been damaged when you pulled the engine out. Could be something around the dizzy stuffing up. Its a bit of a long shot but its a start.

Also a bit rough and rumbly when started cold. Sounds a bit 'burbly'. Goes away once engine warmed. TL VRX. Thought it was normal?

Interesting.

Ash are you talking about the lower part of the intake plenum that meets the engine? or the metal pipe that comes out the back of the intake plenum (near the firewall)?

I did remove the intake plenum to get access to the solenoid attached off one of the brake line mouts on the firewall, but I reattached the same way I always do. Never had much problems with idle. I'll reinspect the intake system for a vacuum leak somewhere.

Might be able get up a video tomorrow to show the noise and vibrations.

where the upper intake manifold meets the lower intake manifold.... the long steel gasket with 6 holes for air and 7 bolt holes

where the upper intake manifold meets the lower intake manifold.... the long steel gasket with 6 holes for air and 7 bolt holes

Ahh yes - exactly what I was thinking. It definitely is attached properly but maybe the gasket has kicked the bucket? I would've thought this would cause issues with the car's performance as a whole. I've never driven a manual magna before but I definitely have much more power than I had before the the 4sp auto.

Gonna give this a :bump:

So I've checked the dizzy and can't see any visible damage. Leads are all connected and don't look crushed at all. I'll need to actually remove them and check their internals.

I seem to have quite jerky deceleration or actually keeping the speed steady. Acceleration is fine however the throttle seems very jerky and rough when I pull back on it. No matter how soft I pull back there's quite a strong jerk as I decelerate. This is much the same with just cruising and keeping a steady speed. The car feels like it is somewhat fighting to stay at the speed. It'd kinda like someone would slightly tap on and off the accelerator every 20 seconds. It feels as if the throttle body is dirty and getting stuck but it wouldn't be because I have cleaned it very well.

Idling is a bit of a mess too. It now sits at 1100rpm on lpg and around 900rpm on petrol but you can physically feel the vibrations. On petrol the car sounds like its hunting and I'm even hearing a very slight knocking noise. I'm thinking that I may need to replace the leads. Lpg is harder on ignition systems so I expect problems on lpg with starting and acceleration but there is none. However there is an issue of the car stalling while driving at certain speeds. Sometimes when I slow down the rpm drops too low (after I go into neutral) and it just straight stalls.

Any ideas?

So here's my list of potential problems:
- Misaligned Dizzy - how do you test this?
- Broken/old leads - can be replaced but I'd rather not spend $100+ if I don't need too.
- Faulty O2 sensor?! - shouldn't I be getting high fuel usage if this was shot. Fuel is pretty much the same economy as when I had the auto gearbox although driving style has changed.

Appreciate the help guys!

Small update: I've ordered Bosch Spark leads from SupercheapAuto. I'm hoping this may help with the rough idle and deceleration problem. Am I on the right track or is this a waste of money?

Also - I'm looking into getting a new distributor cap and rotor. Cheapest place to get them I've been told is from RockAuto.com - which brand should I choose? Do they sell the original ones?

RockAuto seems to have Bosch leads but they have a different item code than the ones I ordered. The ones from Supercheap are B6158i and the ones on RockAuto/Amazon are 09025. What do I make of this?

i'd go for ngk leads and iridium plugs

i'd go for ngk leads and iridium plugs

Cheers for the recommendation. I thought of going Bosch leads because they're lpg compatible. Reading a few threads around here and the general consensus is that Bosch runs well on magna's.

Have you had a different experience or seen others having problems with Bosch leads?

With spark plugs - I've got IridiumIX plugs that are one heat degree colder and smaller gapped because I run lpg most of the time.

the ngk leads are also lpg compatable, i've never been happy with bosch plugs and leads.
my IrIX plugs are just the standard heat range and they havent skipped a beat in the last 70,000km, in fact when i inspected one last service (-7000km) it looked like it did on the day i put it in

the bosch part numbering is probably a market domestication thing.

Not worry - just got a call from SCA - turns out they're unable to get Bosch leads for my car so they're going to order in NGK ones. Perfect!

Before you buy new leads i suggest you check the resistance of the leads on the front bank and see if they are within spec. If so, disconnect the leads for the rear bank 1 at a time (at the distributor) and see if it makes any difference to the poor idle - if it gets worse the lead is OK - if no change the lead is probably shot. If the leads aren't the problem I'd look at the distributor - if the cap and rotor arm look OK, they are probably not the problem. I'd replace the whole distributor, as the power transistor or coil could be stuffed (my 3.5l Verada was running rough as, but i put in a new distributor it now runs great).

I'm with Peteraaa on this one . I like many of the members on here have the dreaded rough/low idle problem . i have followed many peoples advice on what the actual problem is or could be which has lead to excessive spending on my behalf. Though they are routine service items ,it still hasn't fixed the problem.

I have replaced the following with new: fuel filter, ISC, o2 sensor, iridium plugs , custom leads, new battery, new drivers side mount, all silicon vacuum lines.

The only things i am yet to do are the distributor, which i think is a weak coil or TDC sensor, the injectors but i doubt that they are the problem, and a compression test.
I'm doubtful I have a vacuum leak in one of the manifold gaskets as mentioned above. cam angle sensor? coolant temp sensor?.Hopefully my trials and tribulations can aid you.

Before you buy new leads i suggest you check the resistance of the leads on the front bank and see if they are within spec. If so, disconnect the leads for the rear bank 1 at a time (at the distributor) and see if it makes any difference to the poor idle - if it gets worse the lead is OK - if no change the lead is probably shot. If the leads aren't the problem I'd look at the distributor - if the cap and rotor arm look OK, they are probably not the problem. I'd replace the whole distributor, as the power transistor or coil could be stuffed (my 3.5l Verada was running rough as, but i put in a new distributor it now runs great).

Thanks for the advice. The leads I've always wanted to replace anyway. I've got an issue on lpg where if I'm accelerating past 4500rpm the power drops. It feels like the brake has been pushed. I suspect a faulty lead may be to blame.

This idle issue is frustrating as the car was 100% perfect before the manual conversion. None of the engine parts were touched/removed. We didn't remove it but left it hanging on the left engine mount with a jack underneath. The belts/balancers never hit the chassis. The only time I needed to touch the engine was to turn/resist the harmonic balancer so we could loosen/tighten the flywheel. Could the balancer be out of wack?

Thanks for the suggestion. I'll have a look into replacing the dizzy. I've only inspected the dizzy from the outside to see if was knocked/hit when we were fitting up the gearbox. I might have to take it off and inspect the inside.
Where'd you get your dizzy from? I've seen a selection of them available on RockAuto.com - have you got any experience with these or do I cough up the money for expensive mitsu prices? (I'm guessing 2nd hand won't do?)


I'm with Peteraaa on this one . I like many of the members on here have the dreaded rough/low idle problem . i have followed many peoples advice on what the actual problem is or could be which has lead to excessive spending on my behalf. Though they are routine service items ,it still hasn't fixed the problem.

I have replaced the following with new: fuel filter, ISC, o2 sensor, iridium plugs , custom leads, new battery, new drivers side mount, all silicon vacuum lines.

The only things i am yet to do are the distributor, which i think is a weak coil or TDC sensor, the injectors but i doubt that they are the problem, and a compression test.
I'm doubtful I have a vacuum leak in one of the manifold gaskets as mentioned above. cam angle sensor? coolant temp sensor?.Hopefully my trials and tribulations can aid you.

Thanks altera. What a shame you've got this as well and can't get the bottom of it. I've seen a few threads on this and it seems quite difficult to get to the bottom of what could be causing the issue. I'd appreciate any information you'd have with your progress in trying to isolate the problem.

Going by your list of things to check:
Plugs: IridiumIX plugs. Replaced 20,000km's ago. Front bank plugs look fine for another 15,000km at least.
Leads: NGK ones. I'll install these over the weekend. Hope it helps with this problem.
O2 Sensor: I'm quite certain it's not a o2 sensor problem as a bung sensor would cause fuel problems and it's not used when the engine is cold.
Battery: Is a around 3 years old. It has been drained a few times thanks to me leaving the stereo going when I was doing work to the car. It was bought brand new in Jul 09. Would that be causing a rough idle? I can always swap in anouther spare battery I have in the house. How would this be causing a rough idle though?
Drivers side mount: Could be damaged after having the engine hanging off it but I've inspected it and can't find any tears/cracks.
Vacuum lines: Can hear a slight hissing noise when the car is running but all lines are connected from what I can see. Will complete anouther thorough inspection. Intake plenum was removed like many times before and properly refitted. Would a dodgy gasket cause my problem?
Compression test: will conduct one in the coming few weeks. Friend of mine has a tester I'll use.
Coolant temp sensor: Can't see how this got damaged. Radiator replaced. However we did run the car without coolant for a few minutes for testing purposes.

I think I'm going to go to into Mitsubishi and ask them to hook up the MUTII. That should tell me at least if there's a sensor problem.

Thanks for the help everyone! Really appreciated!

Vacuum lines:

I bought a new distributor on eBay for $215 delivered, and it works fine. Don't bother with a second hand - they will cost around $55 and if it doesn't fix the problem you'll be wondering if the second hand distributor was faulty (at least if a new one doesn't fix the problem you know the distributor wasn't the issue). Also, the labour in fitting the distributor is more expensive than the $160 you save using a second hand part which may not work properly (or have a limited lifespan). Interesting you say you flattened your battery because my problem started with a bad alternator, which resulted in low volatage and a flat battery, which i think damaged the power transitor or the coil. By the way, look in your workshop manual for the procedure for checking the primary and secondary coils in the distributor - it's a simple check - all you need is a multimeter and to remove the cap - it may help identify where the fault is.

I bought a new distributor on eBay for $215 delivered, and it works fine. Don't bother with a second hand - they will cost around $55 and if it doesn't fix the problem you'll be wondering if the second hand distributor was faulty (at least if a new one doesn't fix the problem you know the distributor wasn't the issue). Also, the labour in fitting the distributor is more expensive than the $160 you save using a second hand part which may not work properly (or have a limited lifespan). Interesting you say you flattened your battery because my problem started with a bad alternator, which resulted in low volatage and a flat battery, which i think damaged the power transitor or the coil. By the way, look in your workshop manual for the procedure for checking the primary and secondary coils in the distributor - it's a simple check - all you need is a multimeter and to remove the cap - it may help identify where the fault is.

I'd prefer to test and establish that the dizzy is actually stuffed before I spend $100's on buying a new one if I don't need it. I've got the workshop manual and a max ellery service manual so I'll check these for how to test the dizzy. I'm not too fussed with second hand ones as labour is free due to it being done by me and/or my mates - it's just a matter of not buying anouther dud dizzy or one that wears out quick.

I'm not certain if the drained battery caused any problems or not but has been drained a few times before. The battery was removed when we did the manual conversion. It was not touched and just left alone. A week later and it had no charge whatsoever. Could the battery have caused a problem? Surely that would've come up with a battery charge warning light on the centre display?

Thanks for the help buddy :)

Small update: I've ordered Bosch Spark leads from SupercheapAuto. I'm hoping this may help with the rough idle and deceleration problem. Am I on the right track or is this a waste of money?

Also - I'm looking into getting a new distributor cap and rotor. Cheapest place to get them I've been told is from RockAuto.com - which brand should I choose? Do they sell the original ones?

RockAuto seems to have Bosch leads but they have a different item code than the ones I ordered. The ones from Supercheap are B6158i and the ones on RockAuto/Amazon are 09025. What do I make of this?

I would not use Bosch leads on my lawn mower these days, I have had a few sets of late where either the lead is dead or they are arcing, only this morning I assised someone by email with this exact issue with bosch leads arcing

I only use genuine leads, have never had issues with them even when getting on 10 years old.

I would not use Bosch leads on my lawn mower these days, I have had a few sets of late where either the lead is dead or they are arcing, only this morning I assised someone by email with this exact issue with bosch leads arcing

I only use genuine leads, have never had issues with them even when getting on 10 years old.

Thanks for your input Mal. lol I'll stay away from Bosch then.

I was going off some old threads where everyone recommended bosch leads (over topgun ones) but it seems things have changed.
SupercheapAuto were not able to get in Bosch leads in for me anyway so they're given me NGK leads instead. Hopefully it'll work better with my IridiumIX plugs. Any experience(s) with NGK ones? I've heard that the magna's are pretty sensative to changes in leads.

So I've just realised this knocking noise coming from the engine. Any ideas what it could be? I'm considering it may be a misfiring cyclinder?

Vid:

http://www.youtube.com/watch?v=JepE2um1arE

And from the exhaust:

http://www.youtube.com/watch?v=MMWtySXbtjs

Thanks heaps guys for the help!

It might sound like a silly question, but what condition is your catalytic converter in?

It might sound like a silly question, but what condition is your catalytic converter in?

No question is silly! :)

My cat is on its way out. It often has a rotten egg smell - specifically when the car gets pushed a bit. Could a crappy cat be causing a rough idle or the broken metals in the cat are rattling?

Probably not, unless you're experiencing a loss of power, stalling and/or crap fuel economy also. But the source of the rattle may possibly be coming from there if it rattles or creates vibration noises. When the car is dead cold, get under and give the cat a shake to see if there is any loose particles.

Have you checked the voltage going to, or cleaned, the MAF sensor?

Thanks for that Ammerty :)


Probably not, unless you're experiencing a loss of power, stalling and/or crap fuel economy also. But the source of the rattle may possibly be coming from there if it rattles or creates vibration noises. When the car is dead cold, get under and give the cat a shake to see if there is any loose particles.

I know the cat was on its way out but ruled it out for a cause of the rough idle. It definitely does need to be replaced but I've not noticed any significant loss in power or fuel economy, however the car does stall while on lpg once in a while.

The car is dead cold now so I might just duck out and give it a shake. If there's rattling noises coming from inside the cat then I'm going to assume it's totally shot.


Have you checked the voltage going to, or cleaned, the MAF sensor?

I actually have not even given thought to the MAF sensor. How could I miss considering this!
It was removed off the car (with the intake piping) and sat in the boot of my car for a week. The harness was also left open to the elements. I might pull out my multimeter and checked the voltage going to this sensor. What kind of voltage am I looking for?
I'll also check the terminals to see if they're dirty. Is there any other way to check if the sensor is dirty?

Checking the MAF sensor itself, using below, may be a start..

INTAKE AIR TEMPERATURE SENSOR CHECK
1. Disconnect the air flow sensor connectors.
2. Measure resistance between terminals 5 and 6.

Temperature [C] | Resistance (kΩ)
0 | 5.3–6.7
20 | 2.3–3.0
80 | 0.30–0.42

3. Measure resistance while heating the sensor using a hair
drier.

TEMPERATURE | RESISTANCE
-----------------------------------
Higher | Smaller

4. If resistance does not decrease as heat increases, replace
the volume air flow sensor assembly.

Forgive the crude tables, but I trust you get the picture..

Bring out the magnifying glasses, this may also assist you, perhaps..

http://img194.imageshack.us/img194/861/capture20120402201634.png (http://imageshack.us/photo/my-images/194/capture20120402201634.png/) Uploaded with ImageShack.us (http://imageshack.us)

Well it seems I fixed the idling problems! Woohoo :D

I cleaned up the air intake, adjusted the tps, replaced the leads and all seems well.

Turns out that my front tube seals have given way and now I have oil billowing out onto the spark plugs and the leads. One of leads had a cracked rubber casing at the top - rest of them were a bit worn.

Keeping an eye on this but it seems the issue has been resolved. Got anouther dizzy on the way so I'll probably replace mine for good measure.

Thanks heaps to everyone that helped with this. Very much appreciated.

Good news mate, it gives the rest of us with shitty idles hope :)

Unfortunately I have to give this a :bump:

So the dreaded rough idle has returned :(

Recently I've fixed a leaking back rocker cover gasket and installed a sub woofer.

I've checked all connections, plugs, bolts, gaskets and all seem fine. TB looks clean and intake manifold is too. Spark plug leads were changed 8,000kms ago and had no problems since. Spark plugs all in good condition.

Could a battery cause the problem? I'm thinking that my two amps for the sub and the front splits may be putting too much of a drain on the battery? On a cold morning rev's can get as high as 2000rpm. When it gets warm it drops too much. If I turn the sub off, the idle speed goes a little higher and the idle is far less rough (albiet not gone). If I turn the sub on, the idle gets worse.

Poor alternator grounding or an issue with the alternator itself or the wiring to it, perhaps?

Thanks for the quick response!!

Well the wiring to the alternator was moved around when I did the manual conversion and when I had to replace the gearbox about a month ago, but the rough idle has only recently occurred in the last week. Maybe the bolts came loose ot something. I'll check and confirm :)

Alternator is grounded to the factory locations. Amps are grounded with 4guage wire to a bolt below the boot latch. Couldn't see any better place to bolt the cables too.

Are there any other signs of a faulty altenator. I did used to have a alternator whine in my audio system but I attributed that to having the remote wire alongside the RCA cables and not properly grounding the amps. The amp is tacked to the boot floor.

Not sure if this is your problem, but my guess is that your voltage is dropping when you turn on the sub-woofer (because it’s drawing additional current), and the voltage drop is affecting the distributor and therefore the idle.

I had a problem with my alternator some time ago – it wasn’t charging properly, so every couple of weeks the charge warning light would go on for a few minutes and then go off again (I later found out this was due to the alternator brushes being almost completely worn out). Because the problem was intermittent, I did nothing about it, but then the engine began idling rough, got worse with time and eventually died. I replaced the alternator and battery (it was totally flat and was old, so needed replacing anyway) , but it was still idling rough. I read somewhere that running at low voltage can ruin the electronics in the distributor, so I replaced the distributor and now it idles like new. Hope that helps.

Thanks for that peteraaa - I actually replaced the distributor this afternoon. When I originally had the rough idle back a few months ago - I bought a second hand dizzy removed from a car that had no problems on idle. I planned to replace the dizzy back then but since the rough idle disappeared I never bothered.

Haven't taken the car for a drive yet but will do it later tonight and see how it goes.

I think you might be right with the power drain. I did hear somewhere that normal batteries can't supply enough power to run multiple amps. However, I'm not running huge amounts of power (400watts to sub, 100watts to splits) and I don't drive my speakers very hard either.

Is there any way for me to test the power drain on the battery and how to know if it's too much. New batteries are over $150 so if I don't have to buy a new one I won't.

Well I've taken the car out for a bit of a spin tonight and the issue seems to have disappeared again which is great. Car does idle a little too high for my liking at around 1100rpm (petrol) but it does not hunt and is no longer rough on idle.

Removed the dizzy today and seems like the leaking back rocker cover gasket seaped out some oil onto the dizzy. Not sure if that could affect its operation and couldn't find much evidence of the oil really seeping into the dizzy either. Rotor & cap looked fine as well. Replaced the dizzy with second hand one from a car that had no rough idle.

However, I also found a thin vac line that connects the front injector line and to a small pipe on the intake plenum just after the throttle body. This was not connected back on and the car exhibited most of the behaviour before the dizzy replacement. Wondering if after all the work today, that thin vac hose could've been the problem? That'd be a real derp moment.

So now I'm wondering if I should reconnect my sub woofer or get a better battery.
I can't really isolate if the sound system caused the problem with draining the power from the dizzy. I would've thought performance would've been affected by a faulty dizzy but it wasn't. Dizzy's aren't cheap so I don't want to destroy anouther one.
My battery was a fairly pricey battery when it was new ($150) but it is around 3 years old and has been drained countless times during that time. It has a light on it that's suppose to indicate when it needs to be replaced and that hasn't turned on yet.

Just give me a minute to clean the mouthful of coke off my keyboard and I will be right back............................







Now, that done

A pricey battery at $150.....I think not, been drained many times, needs to be replaced

The "little hose" on the fuel rail is the Vac hose for the Pressure Reg, needs to be connected.

A sound system will not harm your distributor unless you are worried about the sound waves wrecking it or something..........

Also, a battery does not have a light to show when it is drained, just think about it, how is a light going to glow when the battery is flat

Have you checked your engine mounts..?

It could just be a bit of vibration coming from an engine mount on its way out.

SuFz :ninja:

:io: right. whatever that was about.

Anyway - will probably need to budget for a new battery. Although it had been drained countless times, I've never had problems with the battery starting or any electrical systems failing so didn't see the need to replace it.

That hose has been connected and the rough idle seems to have gone. New dizzy is also not soaked in oil either so maybe that could've also helped.

Whether don't believe me or not there is actually a small inbuilt indicator that shows green for when the battery is fully charged, black when the battery needs to be charged, and white when it needs to be replaced. I can show you a picture if you're so sure of me just making some random crap about a light on a battery that isn't there.

$150 is somewhat pricey when I can usually get batteries around the $100 mark.

Still not sure if I should reconnect the rest of the sound system in case it does harm to the electrical system. Going to test if my alternator is operating properly first.

.....

Sufz - thanks for your input - my mounts are fine. I recently replaced a broke drivers one and I've inspected all the other ones. No problems there.

what he has is a battery that requires no maintenance

it shows the health of the battery, whether it retains charge and whether it needs replacing - i have one on my car:

http://www.mynrma.com.au/images/services/products-services-nrma-battery.jpg

Have you taken a look at amp draw and also what your alternator is charging at..?

SuFz :ninja:

The battery indicator is not a light, it is a chemical reactive indication

The other points I was simply making were that the pressure reg hose needs connecting and for a decent battery $150 is average price not "pricy" if you want a $100 battery then go get one but $100 is cheap and cheap is usually no quality

Have you taken a look at amp draw and also what your alternator is charging at..?

SuFz :ninja:

I haven't done this yet and will look into testing this out. Can't seem to find much info on how much current the amps draw. Probably need to get the old multimeter out and test it.


The battery indicator is not a light, it is a chemical reactive indication

The other points I was simply making were that the pressure reg hose needs connecting and for a decent battery $150 is average price not "pricy" if you want a $100 battery then go get one but $100 is cheap and cheap is usually no quality

:yeahthat:

The pressure reg hose was reconnected. It's a small hose and it's very hard to get to thanks to all my annoying lpg hoses & wiring.

I'm used to getting the cheapies so might need to up the anti and buy a better battery. Probably get one of those higher current ones.

Get yourself a yellow top.. For the money you spend they're brilliant!

SuFz

I'd love to get one but at $300 for one it's a bit of steep price for a battery. I probably won't keep this car for anouther 2-3 years so I don't see the need to invest so much money into a battery.

rough idle is common on all magnas /veradas ,some more than others
kh veradas (owned two) are more prone to rough idle than kj veradas (owned two).
kh are not adjustable as in idle spped as the ecu will adjust it back but on the kj veradas you can adjust the idle up to smooth it out
i currently own a kh verada and am just use to the idle situation as it is normal for it do this.
maintain and enjoy the car,they are a fantastic car to drive and own!!!

Have you checked your engine mounts..?

It could just be a bit of vibration coming from an engine mount on its way out.

SuFz :ninja:

I second this.
My KH had a bit of a "rough idle" from new. Basically while sitting in drive for more than a minute or so at the lights it would start to kinda seek a little, rpm going up and down. Not enough to register on the taco, although every now and then it kinda dropped and then recovered. Could feel vibration through the seat/floor and could see the passenger seat vibrating a little. Not much and I would consider that normal today in the KH, but my expectation for a new car at that time was that it should be zero. Lol so naive back then.

So back in 2000 I raised a fuss with the dealership and they had a tech and the state manager from Mits come over from Adelaide. I guess they were worried about their rep or something. They decided to replace the cam shaft with a newer version, which hadnt been rolled out as yet at that time, so this was the first one or something, I dk.

The Mits tech supervised the job. Result: no difference.
Years and 180 thousands of ks later I had to replace the engine mounts as the driver side and rear had failed.
Much improved! Still behaves the same, but far less vibration is felt in the cabin.

The moral is that this is normal in the KH but engine mounts can make a big difference. Maybe they weren't sitting right r something.

Well have to bump this up again. Darn car has got a shit idle again. This is giving me the irits, it's up and down like a mad woman's piss.

With petrol, the idle is moderately rough on cold (not massively noticeable) but it's terrible once the car has warmed up. When warm, the engine shakes so bad it rattles my muffler against the heatshield (and it is bolted on properly). You can feel strong shakes through the cabin. Rpm's also drop really low to around 300rpm which is really low for petrol.

The front gearbox/transmission mount (one on under engine crossmember) has a crack, but it's about 40% of the way round. Surely that wouldn't mean you'd feel such nasty roughness on idle?

Also noticing less performance from the car under about 3500rpm. I'm thinking it might the fuel filter or injectors as I'm not using much fuel thanks to the lpg system (and high fuel prices!) ? Going to replace both the filters and get the injectors sonified. Could that be apart of the rough idle problems?

Any ideas?

Potential causes that can be ruled out:
- Dirty TB & ISC - both cleaned out very recently
- Dirty air filter - replaced
- Broken drivers engine mount - recently replaced. Only front engine crossmember mount has small crack.
- Worn out distributor/rotor cap - recently replaced with 2nd hand unit in good condition.

What leads are you using?

NGK leads with NGK Platinum spark plugs.

Spark plugs are one degree colder, and 0.1mm shorter than petrol ones as per the recommendation by NGK.

have you tried hooking up a vacuum gauge to rule out an internal problem?

http://arrc.ebscohost.com/ebsco_static/repair-tips/chiltonimages/tccs/tccs3c01L.gif

Hey, the-ash, what an awesome looking diagram! It's really that simple? Where would you recommend connecting the gauge on a 3rd gen?

If your leads, plugs and everything you described above is in good condition, I would do a compression test. How many km do you have?

Other than that, it could be dirty fuel or a putrid fuel filter.

Thanks guys for the responses!

Ash I haven't done a compression test at all on the engine. Hoping my problem wouldn't be that serious, but it may be the reason. Will head to my local supercheapauto and buy one. When doing the test what do I need to disconnect to prevent the engine from actually starting?

The leads have less than 15000km on them and the plugs have about 40000km on them. Pulled the front ones out recently. Looked good - only slightly brownish and not burnt.

Car has 160000kms now. Wouldn't expect the engine to be damaged or have a problem at only 160km. :/

Where would you recommend connecting the gauge on a 3rd gen?
to a source of constant manifold vacuum, like the "E" port on the throttle body.


Ash I haven't done a compression test at all on the engine. Hoping my problem wouldn't be that serious, but it may be the reason. Will head to my local supercheapauto and buy one. When doing the test what do I need to disconnect to prevent the engine from actually starting?
My suggestion was to perform a vacuum gauge test, but compression test is probably also on the cards (if a little difficult on the rear bank). I'd disconnect the crank angle sensor, to disable the engine.

My suggestion was to perform a vacuum gauge test, but compression test is probably also on the cards (if a little difficult on the rear bank). I'd disconnect the crank angle sensor, to disable the engine.

Thanks heaps for the suggestion!

I thought you gave a different name to a compression test. That would just give me an idea that something is wrong inside the engine, without any indication of what.

The vacuum test seems to be far more comprehensive and give a better indication of problems. Can the tool be purchased for a reason price from an auto-store like Super cheap auto?

Can the tool be purchased for a reason price from an auto-store like Super cheap auto?

well MALZ over here (owned by the guy who founded Marlows, before Supercheap took over) sells them for ~$22 so if supersheep has them then they should be about that price.
https://www.malz.com.au/products/TRST0310

you can find one at any decent auto parts store (repco, covs, etc.)

Annnnnnd anouther bump to this thread...

I've finally got around to buying a vacuum guage. Bought it off fleabay for $25 and it was delivered within 2 days. Can't complain about that!

Hooked it up to the Fuel pressure regulator port ("M" port on the intake manifold - I tried "E" port but got no reading at all) and the needle steadily rose to 20. After a few seconds at 20, it started fluctuating between 19 and 21 (only minor fluctuations, but wasn't 100% dead set steady).
So it seems that I might not actually have an engine problem?

On this website (http://www.secondchancegarage.com/public/186.cfm) it suggests that if I have a reading of 15 and slight fluctuations mean I've got retarded ignition timing fixable by turning the dizzy to advance the timings and/or properly gapping the spark plugs (Scenario 11)
My reading wasn't 15 but exhibits similar behaviours. I did not gap my spark plugs because the manufacturer said not too on the packaging (NGK IridiumIX).

Thoughts on what could be causing a sporadic rough idle on warm?

so is this reading with the fuel pressure regulator disconnected? and is it with the fault present?
if so then get a T-piece and a litle bit of hose so you can have the FPR connected , and take a reading whilst it is faulting.

if you still have it connected then perhaps you could have a sticky EGR Valve... try blanking off the supply pipe from the exhaust to the intake manifold (a blank made from ali can should do)
i recently (4 weeks ago) had a tribute that was exhibiting similar symptoms and it turned out to be the egr sticking open

Thanks heaps for the response Ash.

It's a little late now to fire up my car tonight, but tomorrow I'll use a T-piece to keep the fuel pressure regulator hose still connected to the intake plenum. The kit I bought came with one which is great.

I'll try blanking off the rear re-circ supply pipe. Probably just going to use a thin piece of metal. Should do the job.
Wouldn't be that unexpected for a 160,000km+ car driven mostly in the metro areas to have a sticky/blocked up EGR valve. I've never replaced them and I highly doubt the previous owner did. Are they expensive to buy brand new?

while ive never heard of it on a magna, it is quite common on other makes. but to say its dead is jumping the gun big time and you may just need to remove it, and clean it with carbie cleaner and a tooth brush.

I'll definitely clean them out for good measure. Got a can of throttle body cleaner lying around so I'll make good use of it. Thankfully since I work for Colgate, getting a toothbrush will not be a problem lol lol

On a side note, I found that my rear engine mount is torn with little rubber left holding the engine in place. Obviously a bad mount means the vibrations aren't getting absorbed and hence the engine can shake (appear rough), but surely that would occur also on cold and hot temps? There are times the idle is so bad it's barely above 100rpm and the car feels like it is about to stall.
It also doesn't account for what appears to be a drop in power under 3500-4000rpm. It does however explain why my exhaust would rattle when the rough idle would get quite bad.

Will update with the t-piece fitted on the vacuum guage soon. Was great to see on the guage that nothing appears wrong with the engine.

Re earlier post, dizzy's don't rotate on Magnas to adjust timing, they're fixed. Timing is sorted by crank angle sensor near the timing belts and the ECU. Re EGR valve sticking on Magnas, they certainly can. If giving it a clean make sure you do a thorough job, mine got sticky after giving it a cursory squirt with throttle cleaner...probably turning the soot into tar! Another problem I had re EGR was a dodgy MAF (air flow sensor) giving false data to the ECU which was opening the valve at the wrong time. Plucking the wiring connector off the EGR solenoid (above front bank, passenger side) would make the problem go away if this is the case. Additionally, if the vac lines to and from the EGR solenoid are blocked (or the solenoid is) the valve will be open when it shouldn't be. If blocking the vac line from the solenoid to the A port on the throttle body (yellow stripe usually) by bending it over on itself doesn't make things worse then the system could be blocked. Having said all that, my idle was fine with a leaky EGR, but there was significant power loss (also staggering, stalling etc.) between 1200 - 2200 or thereabouts.

That's also some great advice and input Ensoniq5 - thank you!
(If you haven't been greeted before, then welcome to the club! You should come out to a meet/cruise sometime ;) )

I'll definitely do a thorough clean on that EGR valve and clean out the vac lines plus do a check if the maf sensor is working fine. I've spoken to a few people and they have wondered if the maf sensor is functioning correctly as they're also had similar issues as a result of the MAF sensor. I'll have to conduct a test on that as well.

Cheers mate, I'll keep my eyes open re meet & cruise, sounds like fun.