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Model specific boards => Golf mk3 => Topic started by: sharki786 on 14 October 2010, 18:45

Title: running abit lean
Post by: sharki786 on 14 October 2010, 18:45
my mk3 gti 8v AGG is running abit lean how could that be adjusted?? or it cant?

thanks all
Title: Re: running abit lean
Post by: Khare on 14 October 2010, 18:54
What makes you think its running lean mate?
Title: Re: running abit lean
Post by: Wayne on 14 October 2010, 23:46
my mk3 gti 8v AGG is running abit lean how could that be adjusted?? or it cant?

thanks all

As Khare said what makes you think it is running lean, no way of adjusting it I believe.
Title: Re: running abit lean
Post by: rubjonny on 15 October 2010, 11:12
as above it cant be adjusted, all ecu controlled. main suspects if mixture is wrong is ecu temp sensor and/or lambda probe. as above again, what are the symptoms  :grin:
Title: Re: running abit lean
Post by: DubSociety on 15 October 2010, 11:33
If its a bit juicy on fuel, the only way you can sort it out is:

A. Service it:- Plugs, Oil/Filter, Air Filter,

AND/OR

B. Turn on the trip meter, find out how many miles you do with a tenners worth of fuel for example, and then keep an eye on the trip counter so you know how many miles you got left before you have to visit Mr BP or Mrs Esso again. <-- this way you'll stop doing extra miles, and just generally be more careful with driving around for no reason ...
Title: Re: running abit lean
Post by: sharki786 on 15 October 2010, 13:14
well it smells lean (you can smell the petrol( like yesterday it was coldish and i started the car and there was steam but it smelt petroly, it does under 100miles on £20 vpower. im getting about under 25mpg its 8v agg gti i do give it abit, also a friend of mine has a snapon diag and it blatently came up showing lean
Title: Re: running abit lean
Post by: harlemex on 15 October 2010, 13:26
What is your temperature gauge reading?
Title: Re: running abit lean
Post by: sharki786 on 15 October 2010, 13:30
70-90 depending if im stuck in trafgic or driving khare did say its thermo stat. is there a way of doing the termo without taking timing belt of?? wayne did say that you remove the alternator but someone said you you cant do it like that as the water pump gets stuck? or have i got it wrong?
Title: Re: running abit lean
Post by: harlemex on 15 October 2010, 13:37
Yes you can do it without touching the cam belt. And you do need to remove the alternator and slacken the power steering pump and push out the way abit. All for easier access to get to the flange on the waterpump. Tis a tad awkward but still do-able with some patience. I think it could be why you are using to much fuel. The car will run rich if the engine is running cool.  :smiley:
Title: Re: running abit lean
Post by: dom on 15 October 2010, 13:59
Yes you can do it without touching the cam belt. And you do need to remove the alternator and slacken the power steering pump and push out the way abit. All for easier access to get to the flange on the waterpump. Tis a tad awkward but still do-able with some patience. I think it could be why you are using to much fuel. The car will run rich if the engine is running cool.  :smiley:

+1 sounds like your culprit!
Title: Re: running abit lean
Post by: DubSociety on 15 October 2010, 14:02
100 miles is cr4p ... £20 VPower is basically what? 15 Litres of Petrol right? your driving a 8v aswell ...

Im getting 40-50miles on 8 Litres (£10) fuel, and 70-80miles on 13Litres (£15) and im driving a 16v and also give it a bit on straight roads etc. In town/traffic I coast the car a lot where I can.

Theirs definitely a culprit somewhere ... sounds like an easy fix though.
Title: Re: running abit lean
Post by: Wayne on 15 October 2010, 14:04
well it smells lean (you can smell the petrol( like yesterday it was coldish and i started the car and there was steam but it smelt petroly, it does under 100miles on £20 vpower. im getting about under 25mpg its 8v agg gti i do give it abit, also a friend of mine has a snapon diag and it blatently came up showing lean

I would add that suggests not running lean but overfueling.

Has it had a temp sender replaced, if not could be a good place to start.
Title: Re: running abit lean
Post by: DubSociety on 15 October 2010, 14:08
well it smells lean (you can smell the petrol( like yesterday it was coldish and i started the car and there was steam but it smelt petroly, it does under 100miles on £20 vpower. im getting about under 25mpg its 8v agg gti i do give it abit, also a friend of mine has a snapon diag and it blatently came up showing lean

I would add that suggests not running lean but overfueling.

Has it had a temp sender replaced, if not could be a good place to start.

+1
Title: Re: running abit lean
Post by: dom on 15 October 2010, 14:23
100 miles is cr4p ... £20 VPower is basically what? 15 Litres of Petrol right? your driving a 8v aswell ...
Im getting 40-50miles on 8 Litres (£10) fuel, and 70-80miles on 13Litres (£15) and im driving a 16v and also give it a bit on straight roads etc. In town/traffic I coast the car a lot where I can.

Theirs definitely a culprit somewhere ... sounds like an easy fix though.

That's not that crap tbh, if your getting 100 miles per 15 litres that works out to be roughly 30mpg. Depending upon driving style and the type of driving that figure is very realistic.
Title: Re: running abit lean
Post by: rubjonny on 15 October 2010, 15:15
where did you put the snapon tester? if up the tailpipe yeah it';ll be showing lean due to the cat. you need to use the sniffer pipe to the manifold. apologies if thats what you did :)

can rule out the lambda probe simply by unplugging it, if car runs much better you likely need a new one. other than that get it on vag-com to check for faults, and read the measuring blocks to see what values ecu is seeing for ecu temp, throttle position etc.
Title: Re: running abit lean
Post by: Khare on 15 October 2010, 15:17
100 miles from 20 quid isn't too bad. It's about average. The stat deffo won't help as the car will be running cool, so the coolant temp sensor gives the ecu the signal to dump fuel in, which is how it works when the engine is cold. The stat is a 20 minute job, remove pas pump and belt and the stat housing is right there with the 2 10mm I think, screws looking right at you. Make sure you fit the stat the right way round. As I said, 20 minute job. Remember you have to refilled the entire cooling system after this job, and while the stat is out, I'd flush the complete system with a garden hose, as the only proper way is by removing the stat.
Title: Re: running abit lean
Post by: sharki786 on 15 October 2010, 21:56
where did you put the snapon tester? if up the tailpipe yeah it';ll be showing lean due to the cat. you need to use the sniffer pipe to the manifold. apologies if thats what you did :)

can rule out the lambda probe simply by unplugging it, if car runs much better you likely need a new one. other than that get it on vag-com to check for faults, and read the measuring blocks to see what values ecu is seeing for ecu temp, throttle position etc.

it was pluged in to the odb diagnostic port next to the ashtray, the lambda sensor has been replaced about 2yrs now. id know if the lamda sensor was fooked (the car would be bounching revs from 1000-2000 rpms
Title: Re: running abit lean
Post by: Wayne on 15 October 2010, 23:28
To me it is overfueling not running lean, I would get the emissions checked before the cat by a proper exhaust gas tester.
Title: Re: running abit lean
Post by: rubjonny on 18 October 2010, 10:03
they dont always fail like that though. what make of lambda is it?