Underboosting - any help - advice ??? Thanks...

[mmm777]

For me is really sad, see my car is doesn't working properly, 2 garages said to me car is overboosting, because was chipped, I remove chip, still same problem with hesitation, just little less becuase is standard 150 only, 3 garage told me is under boost..., but they can't find fault..., i feel like I just wasting money on garages, without any result...., I don't know what can I do.., I got vag - com , but no any error codes at all..., really thanks for any help or advice...

[Raging Insanity]

Hi,

I also have a 2000 Audi A6 1.8T SE (manual) which has been remapped using Revotechnik software. The engine code is APU.

I smelt some burning smell about 9 months after it was remapped, but could not locate any oil or fluid leaks. There was minor smoke coming from the right hand side low down in the engine, but it stopped and subsided quickly whenever I smelt it and so I could not find where it came from. It did not always do it.

At the moment, my turbo comes on intermittently and certainly does not have the right amount of boost when it does. I had the car go through a normal service with a VAG-COM diagnostic session which recorded no fault codes. However, the requested boost was going through fine, but the actual boost was lagging for a while until it made the proper amount later than it should. I know that at higher RPM (>4500) the boost dissipates and the engine wails (not the turbo). I was advised it could be a dodgy MAF or N75 valve.

I changed the MAF - no difference.
I changed the N75 - slightly better, but not as it was.

Something is still wrong and I am getting told it could be the wastegate valve just above the N75, or the turbo actuator (which seems more likely but is a pain to replace if your not used to ripping out everything on one side of the engine).

Have you had any more news? What have you tried? Maybe between us we can figure out what it is if we have done different things.

Cheers,
RagingInsanity

[mmm777]

Hi mate, my problem was funny N75 valve, inside was small piece of rubber and this make hesitation, I cleaned and was just fine, but I replace standard n75 valve fof n75 J valve and is much better, boost is smooth and keeped much longer.., and check on your car diverter valve , I put it one from miltex and is much better, this is very important and MAP sensor - this fault doesn't come on vag-com, with smoke I can't help you I don't know, can be anything, maybe really small crack on oil pipe.., try check this thinks and let me know...


mmm777