If my car is burning oil inside the engine with fuel ... ?
08-28-2008, 07:32 AM
#1
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If my car is burning oil inside the engine with fuel ... ?
INTRO: My car (98 Audi A4 - AHA - 123000 miles) has been running rich for some time now with an abnormal fuel trim and throwing the following fault code:
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-00 - -
The fuel trim values creep up on both banks each day until the CEL finally lights and learning stops until the ECU is reset. Bank 1 is always consistently much higher than Bank 2. Here is a snapshot of my current fuel trim:
Measuring block group 32:
O2S control learning values (before Cat. Conv.) [B=Bank S=Sensor]
-4.7 % @idle B1S1 +/-10%
-16.3 % @part B1S1 +/-10%
-3.7 % @idle B2S1 +/-10%
-8.2 % @part B2S1 +/-10%
I have been unable to resolve this issue with the usual tests & fixes: MAF, plugs, wires, coil, fuel filter, fuel injectors, fuel pressure regulator, camshaft position sensor, engine coolant temp. sensor, small vacuum lines, cleaning throttle body.
Having eliminated all these possible problems, I'm left with the theory that maybe the car is burning some engine oil with the fuel, and this results in the O2 sensors reporting less oxygen than expected and the ECU cuts fuel and causes the engine to actually run lean.
MY QUESTION: If the engine is actually burning oil with fuel, what would need to be done to fix that? Other than noticing white smoke in the exhaust (I really don't see any), is there a scientific method to check if this is happening? Are there several points of failure inside the engine that could cause this, or is there just one definite thing to check/fix to stop it? How much oil do I have to be losing to prove or eliminate the possibility that this is happening?
BTW - the car also has a small oil leak, and in 3 months it has lost almost a quart of oil. After driving the car and then parking it, oil burning smoke starts to rise from underneath the engine (more smoke coming up from under bank 2 than bank 1, but definitely coming up from under both banks), we think that is the oil starting to leak out onto the side of the hot engine as it settles down. It has been suggested that changing the valve covers should stop that leak. Could the same leak of oil to the exterior of the engine also be the source of oil getting into the engine to burn with the fuel?
Much appreciation for your thoughts, as always.
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-00 - -
The fuel trim values creep up on both banks each day until the CEL finally lights and learning stops until the ECU is reset. Bank 1 is always consistently much higher than Bank 2. Here is a snapshot of my current fuel trim:
Measuring block group 32:
O2S control learning values (before Cat. Conv.) [B=Bank S=Sensor]
-4.7 % @idle B1S1 +/-10%
-16.3 % @part B1S1 +/-10%
-3.7 % @idle B2S1 +/-10%
-8.2 % @part B2S1 +/-10%
I have been unable to resolve this issue with the usual tests & fixes: MAF, plugs, wires, coil, fuel filter, fuel injectors, fuel pressure regulator, camshaft position sensor, engine coolant temp. sensor, small vacuum lines, cleaning throttle body.
Having eliminated all these possible problems, I'm left with the theory that maybe the car is burning some engine oil with the fuel, and this results in the O2 sensors reporting less oxygen than expected and the ECU cuts fuel and causes the engine to actually run lean.
MY QUESTION: If the engine is actually burning oil with fuel, what would need to be done to fix that? Other than noticing white smoke in the exhaust (I really don't see any), is there a scientific method to check if this is happening? Are there several points of failure inside the engine that could cause this, or is there just one definite thing to check/fix to stop it? How much oil do I have to be losing to prove or eliminate the possibility that this is happening?
BTW - the car also has a small oil leak, and in 3 months it has lost almost a quart of oil. After driving the car and then parking it, oil burning smoke starts to rise from underneath the engine (more smoke coming up from under bank 2 than bank 1, but definitely coming up from under both banks), we think that is the oil starting to leak out onto the side of the hot engine as it settles down. It has been suggested that changing the valve covers should stop that leak. Could the same leak of oil to the exterior of the engine also be the source of oil getting into the engine to burn with the fuel?
Much appreciation for your thoughts, as always.
08-28-2008, 07:49 AM
#4
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Sorry. Didn't know what that meant. Kind of sad because...
...I had a 98 30v. I remember there was a "T" connection for vaccum hoses towards the back of the engine that made the car run rich and the replacement at the dealer was metal instead of plastic. Sorry I don't remember exaclty where.
08-28-2008, 08:08 AM
#5
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You mean the platic vaccuum-T in the middle of the plate in this photo
<center><img src="http://pictureposter.audiworld.com/148128/dsc00348.jpg"></center><p>Actually, there are two T's.
I changed all those aged small vacuum lines in the photo above, I don't think it is a vacuum leak there. Had hoped at the time that it was.
I changed all those aged small vacuum lines in the photo above, I don't think it is a vacuum leak there. Had hoped at the time that it was.
08-28-2008, 08:12 AM
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I'm sure it's the one with the two bluish and yelowish hose to it. It was a simple plastic T.
BTW last week I was getting the P1127 on my 1.8 and it was because of a torn hose. Those things are a pain in the *** and they're everywhere. I'd keep looking. Good luck.
