running lean 17544 + revs higher 16891

[blackpool1974]

Hi,

Had my A4 Cab 1.8T serviced recently and since then been getting engine dash light appearing occasionally.

Can drive for 500 miles (motorway) and then as soon as I stop it comes on, or if you leave the car idling for 30 mins it comes on

I have studied measuring blocks for engine (032 lambda idle) and window 1 goes from 0 upto 10% when I reset the fault code within minutes indicating its running lean, but the 2nd window which apparently means lambda not idle is not as bad, just had the car back at an Audi specialist who says he can't find the cause.

I suspected an air leak but the garage can't find it

Over to you guys !!!



VAG-COM Version: Release 409.1-US

Control Module Part Number: 8E0 909 518 AL
Component and/or Version: 1.8L R4/5VT G 0003
Software Coding: 0011584
Work Shop Code: WSC 00672

2 Faults Found:

17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 001 - Upper Limit Exceeded

16891 - Idle Control System RPM Higher than Expected.
P0507 - 001 - Upper Limit Exceeded - Intermittent

[geeza]

hi did you ever get this sorted as ive got the 2 same codes on my 2004 a4 1.8t cab

[Crasher]

I looked at this chaps car a few weeks ago for half an hour and decided to try a new Air Mass Meter which I thought had cured it but the problem came back later and I have not been able to work on it since. I have a feeling it is an air leak from under the variable cam timing unit but a charge air system leak test is required to detect this and that requires a special VAG tool set which costs around £400, which I do have. If he comes back to me, that is what I would like to try. I checked his breather pipes and all looked perfect.

[blackpool1974]

Observations so far are that it over revs only in Neutral or Park (I have Multitronic)

When the engine is hot it over revs, when cold it idles fine, still runs lean though.

Have you had to replace your PCV (black piece of plastic shaped like a spaceship at the back of the engine ?? I have had to replace mine 3 times in 6 months, something to do with the crankcase breather system ??

Have you got manual or auto ?? I have read that some people think it is the auto gearbox not getting out of gear correctly ?? (dont believe that though)

I have checked my throttle valve and that is spotless, still could be faulty though, but wouldnt answer the lean part of the problem

Question for Crasher, could a leaky Rocker cover gasket cause this problem ?? as I have noticed a bit of oil in my plug chambers, also when I took my throttle valve apart, didnt seem to be much of a gasket there although it looks tight

[Crasher]

The throttle valve has a gasket which changes according to year.

The problem I have seen is due to the cam chain adjuster at the back of the head leaking.

[blackpool1974]

Had to bite the bullet and go to Audi, they reckon its the crankcase breather valve under the manifold ??

They say deffo no air leak

Booked in Wednesday, will keep you informed

[blackpool1974]

It was the breather valve.

£15 part £175 labour by Audi to fit it !!!

Pulls like a train now

[Crasher]

I had one fail on a Golf 5 GTI last week, never seen it before on a Golf 5, it was leaking around the diaphragm top cover but that one you have is the exact same part that has been used for 35 years and I have never ever seen one fail!