2006 Audi A6 Quattro Avant History
tldr; Changed ECU a year ago, since then engine oscillates on and off at a slow steady speed, gotten really bad on cold start.
Had a two-year plus problem with failing LDAP - in the end the problem was the ECU (mosty likely a burned out driver). The dealer wanted $2000 to replace it, maybe it would fix the problem maybe not. In the end I bought a used one for $100 or so and sent it to Jack@European_Parts to reprogram, which he did.
I really didn't do anything after installing it and the car seemed OK when I drove it around the block. Its my wife daily car and didn't think much about it since she was happy to not see the dreaded light on the dash (after 2 years!). Some time later - weeks - I drove the car and found it "hunting" when trying to hold a steady speed. At that point I did a Throttle Adaption using VCDS but the problem still seemed to be there. I was told to do all the adaptions possible, but never found anything in the Bentley or VCDS documentation that told me WHAT adaptions to do.
I took the car to Audi for a safety recall, asked them to fix the problem, they said there is no problem they can detect. That was a year ago.
Since then the problem has gotten progressively worse, and I'm posting this in the hope I get some tracking the problem down before another visit to the dealer. Since the ECU, the only changes to the car are an old change.
Details:
- have done 10 throttle adaptions, once leaning over the engine so I could hear the throttle moving - no change
- tested the accellerator pedal using VCDS - voltage is smooth, no jumps, and values consistent with what other posts
- on summer time cold start, go 10 MPH up the driveway, the car lurches, as if the engine catches then stalls
- even when warm, the problem is most noticeable at 20-25 MPH - the dash tach is smooth, but the engine is obviously trying to find something, as it surges then stalls at about 1 per second.
- the problem is also noticeable at highway speeds (60-70MPH) but is of lower intensity
- at full acceleration, no problem
- at idle, engine is smooth as a new one
Is it possible some Engine Adaption would be relevant? Sensor that doesn't generate an engine fault code?
tldr; Changed ECU a year ago, since then engine oscillates on and off at a slow steady speed, gotten really bad on cold start.
Had a two-year plus problem with failing LDAP - in the end the problem was the ECU (mosty likely a burned out driver). The dealer wanted $2000 to replace it, maybe it would fix the problem maybe not. In the end I bought a used one for $100 or so and sent it to Jack@European_Parts to reprogram, which he did.
I really didn't do anything after installing it and the car seemed OK when I drove it around the block. Its my wife daily car and didn't think much about it since she was happy to not see the dreaded light on the dash (after 2 years!). Some time later - weeks - I drove the car and found it "hunting" when trying to hold a steady speed. At that point I did a Throttle Adaption using VCDS but the problem still seemed to be there. I was told to do all the adaptions possible, but never found anything in the Bentley or VCDS documentation that told me WHAT adaptions to do.
I took the car to Audi for a safety recall, asked them to fix the problem, they said there is no problem they can detect. That was a year ago.
Since then the problem has gotten progressively worse, and I'm posting this in the hope I get some tracking the problem down before another visit to the dealer. Since the ECU, the only changes to the car are an old change.
Details:
- have done 10 throttle adaptions, once leaning over the engine so I could hear the throttle moving - no change
- tested the accellerator pedal using VCDS - voltage is smooth, no jumps, and values consistent with what other posts
- on summer time cold start, go 10 MPH up the driveway, the car lurches, as if the engine catches then stalls
- even when warm, the problem is most noticeable at 20-25 MPH - the dash tach is smooth, but the engine is obviously trying to find something, as it surges then stalls at about 1 per second.
- the problem is also noticeable at highway speeds (60-70MPH) but is of lower intensity
- at full acceleration, no problem
- at idle, engine is smooth as a new one
Is it possible some Engine Adaption would be relevant? Sensor that doesn't generate an engine fault code?
