My TJ 3.5L auto used to get about 460-480km to a tank before the low fuel warning lights comes on. Now, it's on at around 420km. Could this be due to a dirty air filter or a dirty fuel injector?

I've tried putting in fuel injector cleaner into the tank but it doesn't seem to help. Car is now at 99,000km. Last have air filter replaced at 83,000km and fuel injector cleaned by service at 45,000km.

Change spark plugs..:)

Also look at the O2 sensor, might have burnt out

How does spark plugs relate to fuel consumption?

Could be a multitude of reasons really but a few easy ones to try are keeping your tyre pressures up and balanced (keep a pressure gauge in your car) and checking for uneven tyre wear.

Disconnect your battery for a good while and then reconnect it... let it re-learn again... often this can be a surprisingly good way to get your car to get it's brain back in order.

Get a service and tune if it is due.

There are other things that could be causing it some other tech heads can give guidance on.

Could be a multitude of reasons really but a few easy ones to try are keeping your tyre pressures up and balanced (keep a pressure gauge in your car) and checking for uneven tyre wear.

Disconnect your battery for a good while and then reconnect it... let it re-learn again... often this can be a surprisingly good way to get your car to get it's brain back in order.

Get a service and tune if it is due.

There are other things that could be causing it some other tech heads can give guidance on.

I've inflated the tyres to 37psi... and I very rarely do hard acceleration/braking. Maybe get it to service if no other options. I was hoping to skip the 100k service and just get oil + oil filter change, check other levels myself to save a few bucks.

I've inflated the tyres to 37psi... and I very rarely do hard acceleration/braking. Maybe get it to service if no other options. I was hoping to skip the 100k service and just get oil + oil filter change, check other levels myself to save a few bucks.

before the vultures pick this apart, ill say it once. You NEVER EVER (insert loud noises and flouro lighting here) cut corners when servicing, what might be a 600 service of a timing belt can and will turn into a 1500+ rebuild of heads/motor job within a matter of seconds literally. The 100k service is there for a reason.

before the vultures pick this apart, ill say it once. You NEVER EVER (insert loud noises and flouro lighting here) cut corners when servicing, what might be a 600 service of a timing belt can and will turn into a 1500+ rebuild of heads/motor job within a matter of seconds literally. The 100k service is there for a reason.

My timing belt was replaced in the 83k service.

My timing belt was replaced in the 83k service.

Why was it changed so early? snapped? tensioner making funky noises?

Why was it changed so early? snapped? tensioner making funky noises?

Because my car is 2000 built. You are suppose to change it at 100k or 5 years. I changed it on the 6th year.

Yeah my timing was changed at 52000kms for age reasons.

What about the rear spark plugs? They are due for change at the 100k service.

Yeah my timing was changed at 52000kms for age reasons.
Almost sounds a little extreme :think:

What about the rear spark plugs? They are due for change at the 100k service.

That's what I am trying to ask on the other thread.... what am I risking if I delay the spark plugs to 120k.

How often does the fuel injector need to be professionally cleaned by service?

How often does the fuel injector need to be professionally cleaned by service?
mine havent been done for 150,000 k's but i am getting them done soon as i reckon its good for performance (and economy i guess)

Air filter should be replaced every 7500-10000kms and checked every 5000 (Depending on where you are driving, city=7500, country=10000) - 16000 is a bit excessive. I'd be replacing it asap.

Also try revving it - Any black or white smoke from the exhaust?

And what colour is your oil?

Air filter should be replaced every 7500-10000kms and checked every 5000 (Depending on where you are driving, city=7500, country=10000) - 16000 is a bit excessive. I'd be replacing it asap.

Also try revving it - Any black or white smoke from the exhaust?

And what colour is your oil?

Stupid question, but how do I tell?
Can a noob replace air filter themselves? If so, how much do they sell for and where?

Air filter is easy to replace yourself. On the passenger side of the engine bay there is some black plastic tubing that widens out over the radiator. If you look towards the firewall along that pipe you will see two clips. Undo those and you can pull the air filter out.

even if it looks fine it would still be dirty.. just pop into repco and get a silverline air filter.. there like $29 RRP! (significantly less trade)

I'm using 10W-30 Repco oil now (on the pack it says it's made by Mobil). They have a really good deal if you get their filters with their oil at the same time (like $50 for oil + filter + air filter). MMAL air filters are about $40!

They have oil/air/fuel/transmission filters for Magnas.

Good luck with the fuel consumption. You could try using the a/c less too :)

a/c useage doesn't seem to affect mine very much at all IF anything..

thinner oil (depending on age and condition of the engine) could help..

like if someone put 20w50 in a 01 with 120 km's on it.. when it should need 10w30 etc etc..

a/c useage doesn't seem to affect mine very much at all IF anything..

AC never seemed to affect the economy in my Verada either. Haven't really had the TL long enough to notice if it does or not (all I notice is the improved economy over the Verada lol)

Air filter should be replaced every 7500-10000kms and checked every 5000 (Depending on where you are driving, city=7500, country=10000) - 16000 is a bit excessive. I'd be replacing it asap.

Also try revving it - Any black or white smoke from the exhaust?

And what colour is your oil?


Funny you should mention that, all my cars get really black air filters, i think its because i drive through the M5 tunnel every day!
The air is so dirty in there!

Funny you should mention that, all my cars get really black air filters, i think its because i drive through the M5 tunnel every day!
The air is so dirty in there!
That'd prob do it. I replace mine a bit more often now I'm in North Ryde - down in the country areas there was hardly any pollution. Up here its crazy. LCT/M5 tunnels ftw.

I was getting 9.7 l/100klm around town but disconnected my battery the other day and now it's up to 12.6 l/100klm. Due for a service soon but might have a go at resetting the computer.

you could always go for a k+n filter and just clean it every 5 to 10000 k's.....:D

even if it looks fine it would still be dirty.. just pop into repco and get a silverline air filter.. there like $29 RRP! (significantly less trade)

Fork out for a K&N panel.

+1:stoopid:

get the "fuel sender unit" transmitter which is located under back seat checked by your service guy, this has happened twice to me over the years - 1st in my old tl vrx then again in my current kf ei verada - causes the fuel guage & trip computer to give incorrect level of fuel left in tank, they seem to go faulty every 100,000 km's or so - TAKE IT FROM SOMEONE WHO KNOWS!!!!!!!!!!!!!!!!!
IE - COULD ONLY GET 350 KM BEFORE 1/4 TANK - NEW SENSOR, BACK TO 650 KM BEFORE 1/4 OF TANK IN BOTH CARS

That's what I am trying to ask on the other thread.... what am I risking if I delay the spark plugs to 120k.
I wouldn't. I did (the belts and everything else had been done) because I couldn't get time off work to get it serviced (no public transport to where I work, and its a 60km round trip), and I can tell you it made a huge difference (117K km in my case). Much smoother and significantly better fuel consumption. Get a local mechanic to do it (not a dealer - I've been buggered by them this year - Grrrr!)

I wouldn't. I did (the belts and everything else had been done) because I couldn't get time off work to get it serviced (no public transport to where I work, and its a 60km round trip), and I can tell you it made a huge difference (117K km in my case). Much smoother and significantly better fuel consumption. Get a local mechanic to do it (not a dealer - I've been buggered by them this year - Grrrr!)

Im lucky,

I have a mechanic that comes to me lol He services around 12-14 magna's, he knows them backwards which means it doesnt take him long to do anything :)

I only get around 440km MAX from 68 litres of fuel i.e. 15litres per hundred mixed driving. Also engine runs a bit too rough for my liking... any ideas?

I only get around 440km MAX from 68 litres of fuel i.e. 15litres per hundred mixed driving. Also engine runs a bit too rough for my liking... any ideas?

As said in this thread around 100 times, O2 sensor.

could also be dirty (or worst case leaking) injectors..

and NO 'injector cleaner in a bottle' will fix it..

pop them out, and drop them to an injector place.. a local guy here in brisbane does them for around $20-$25 each wich i belive is about the going rate for most places..

ultrasonic clean, new filters, flow test/and spray pattern check

mat.

I've done the rear + front spark plugs, plus have the fuel injectors professionally cleaned, but the fuel economy isn't any better. Tyres are at 36psi. What can I do to fix it? Someone mentioned the O2 sensor maybe faulty, is there a way to find out myself?