A8 Parts Forum

A8 Parts Forum (http://forum.a8parts.co.uk/index.php)
-   D3 - Common Faults (http://forum.a8parts.co.uk/forumdisplay.php?f=67)
-   -   running too lean (http://forum.a8parts.co.uk/showthread.php?t=3213)

reiss 25th June 2011 04:01 PM

running too lean
 
Hi my engine management lights come on on my d3 audi a8 4.2 v8 after a diagnostic its showing as running too lean could anyone enlighten me as to what needs replacing or fixing and why its showing this fault

ADU UR quattro 26th June 2011 12:19 PM

I would check fault codes to start with.what part of the world are you in, there must be some one near by with vagcom, that would be willing to plug it in for you.

ainarssems 26th June 2011 12:31 PM

First you need to determine if it is actually running lean or if ii just thinks that it is running too lean.

If it is just thinking that it is running too lean then it's faulty lambdas.

Otherwise it could vacuum leak, faulty MAF or not enough fuel due fuel pressure regulator, fuel pump, clogged fuel filter or injector.

A8 Doc 11th July 2011 02:36 PM

Do a lambda test in VAGCOM if I were you. Lambdas are a biatch to get to on these. Hopefully the MAF is at fault :D

reiss 11th July 2011 03:29 PM

Quote:

Originally Posted by A8 Doc (Post 24606)
Do a lambda test in VAGCOM if I were you. Lambdas are a biatch to get to on these. Hopefully the MAF is at fault :D

its showing as running too lean bank 1 i always use shell v power someones told me to be very careful as driving it could be damaging engine

A8 Doc 19th July 2011 04:59 PM

Quote:

Originally Posted by reiss (Post 24607)
its showing as running too lean bank 1 i always use shell v power someones told me to be very careful as driving it could be damaging engine

Yes it certainly could be.

As it says just one bank I would suspect possibly an injector or lambda.

In Vagcom you can do a lambda load test, I suggest you do this as it individually does each lambda sensor to check it.

Check your injectors as well.

Just_Ben 19th July 2011 05:54 PM

Check inlet manifold is tight! They come loose and draw unmetered air in.

Failing that, secondary air system leaking or split vacuum pipes are most likely.

ainarssems 19th July 2011 06:38 PM

Would not vacuum leak affect both banks instead just one?

reiss 21st July 2011 08:34 PM

Quote:

Originally Posted by A8 Doc (Post 25042)
Yes it certainly could be.

As it says just one bank I would suspect possibly an injector or lambda.

In Vagcom you can do a lambda load test, I suggest you do this as it individually does each lambda sensor to check it.

Check your injectors as well.

could you tell me how to do the lambda load test on the Vagcom?

Just_Ben 22nd July 2011 09:29 AM

Quote:

Originally Posted by ainarssems (Post 25050)
Would not vacuum leak affect both banks instead just one?

No, the fault code designation is funny so it sometimes only logs one bank, just to confuse ya!


All times are GMT. The time now is 01:57 AM.

Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.