Hello.
I have a 01 reg 1.8T Audi A6. About 2 months ago i noticed the trip computer averaging 15 to the gallon and a very strong smell of petrol, so i took it to my usual garage who did a code read - P1128 and P1136 = Bank 1 mixture adaption too lean !
So i had a new Lambda Sensor fitted - still the same, so then had a new Mass Air Meter - Then a new Thermostat and i also had the Throttle Body cleaned - still the same problem, The EML still comes on MPG is awful and a very strong smell of fuel coming from the tail of the exhaust. How can it be running Too Lean when it is running Too Rich !
So my garage put me in touch with a Bosch Service Centre who worked on the car for 6 hours, doing all checks relating to Fuel and Air.
The car has no air leaks, all new parts work correctly, Coil packs are fine, i also had the exhaust and cat checked - both fine.
Last Friday i had the codes re-set and seemed better for a while until the EML came on again and back to square one again with poor tick - over , loss of power , smell of fuel, black smoke coming out exhaust etc Could someone please help me here with some good advice or suggestions because i am at the end of my teather with this problem not mentioning how much it is costing me . Please Help !
Regards Steeley
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The ECU is told that the engine is running LEAN and it therefore richens the mixture-if the sensors still tell the ECU that the engine is still running LEAN,it adds more and more fuel.
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Hi
So could it be possible for a Lambda sensor to appear working fine , give a false reading to the ECU ! OR could the ECU be faulty !
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where did you get the maf and the lambda sensor ?
A lot of the cheap ones either plain don't work or don't work very well. These are two of the bits that I would only buy originals for.
Is the car modified at all?
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The Lambda sensor the garage fitted was genuine Audi, so i called them and they say they can check to see if sensor is working but if its ok they will want £97.50 plus vat for looking and cant get me in until the 23rd of this month. What a nightmare !
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Hi
I know the Lambda is genuine but not sure about the maf ! i will call the garage tomorrow to find out. No the car has never been modified to my knowledge.
I have owned the car for 2 years and its been fantastic until these problems came along.
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Hello
Here is the Job desctiption from the Bosch Service Centre. Who spent 6 hours trying to find the faults.
Code read ( Advanced )
Diagnose faults through Measuring Blocks
All units related to air & fuel components tested & checked.
All unit readings correct
Fault codes indicate lean mixture. C/o reading very high
Further investigation required with new parts to be fitted to obtain correct running figures.
What else could this problem be !!! any ideas or advice grarefully received on this matter.
Regards Steeley.
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I suggest you post this problem here as well.
www.vwaudiforum.co.uk/forum/forumdisplay.php?f=25&...c
Regards Peter
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Hello
Thanks for the link Peter D. I have already posted on there forum but yet to receive any response. I think this problem has got many people stumped. All the obvious parts have either been replaced or checked. Its a real headbanger. I will take it back to garage this week for a last attempt to cure this. failing that i will have to chop it in. I cannot keep spending my money on a car that no one seems able to fix.
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steeley
I don't see much sign of proper diagnostics here - just a load of poke-and-hope. No wonder they can't find it.
First; what's the engine code? Second; what is the front wideband oxygen sensor [unlikely to have a "Lambda" on this one] reading at idle and part load? What are the 4 gas readings under the same conditions - particularly the oxygen percentage?
Has anyone used a smoke machine to check for exhaust manifold leaks?
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Hello
I have just driven to our local supermarket. The car still the same. EML still on, the smell of burning petrol is shocking and car still in limp mode. The trip cpu showing 16 miles per gallon instead of 33. costing me a fortune. Any ideas !
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Hello
Thanks for responding Screwloose. The engine number is AWT049682 2001 1.8T SE
not sure of readings tech guy say c/o very high indeed. As far as i am aware the car has 2 lambda sensors, one on manifold and one on the drivers side which is clearly visible. I know the garage only replaced one of them, which one i am unsure. A guy from exhaust centre check exhaust , he said its fine although he never used a gas tester. Have you any suggestions on what this fault could be !
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steeley
I've got loads of suggestions - how much do you want to spend trying them all? This fault could be many things - but your biggest problem is that guesswork just isn't working.
All the data needed to define the fault is available - to anyone with a brain to use it. Throwing parts at it just wastes money.
Those 2 codes appear to show an excess of oxygen in the exhaust under all conditions.
WHY?
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So far it has cost me £750 and i still have a knackered car. Do you think i should get the exhaust gas tested !
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Yes; as part of a concerted examination to discover why a car that's running rich still has high levels of oxygen in the exhaust manifold? The CO level is irrelevant - the nose-gas tells you it's rich - it's the oxygen level that's of interest.
Crack in the manifold? Exhaust manifold gasket? Turbo leak? Misfire? Valve gone? I'd have a smoke machine on that exhaust before even plugging the scanner in.
[Check the source of that MAF too - non-gen..... Bin it - or put it on e-bay with all the other fakes.]
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Hello
I will get it checked tomorrow without fail.
That would explain how all these so called experts have failed to resolve this problem. they have been looking in the wrong places and why all these parts concerning the fault all check out ok.
Big thanks Screwloose for your time and expertise. I will keep you up to speed on developments. Cheers Mate
Regards Steeley.
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Hi Steeley,
Did you ever resolve this problem with your A6, as I have exactly the same problem with my Quattro 1.8T (YEAR 2001 WITH ONLY 68000 MILES ON CLOCK)? Have replaced everything you have and still the same fuel smell etc- all same problems exactly. Can you or anyone assist.
If so send me email to rogert.kelly@btopenworld.com. Thanks
Edited by seltech on 08/08/2008 at 00:46
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