My 80,000 mile 2.0TFSI Turbo Audi has lost a lot of performance but produces no check-engine-light (CEL) or codes. One month ago an independent garage looked at it and did $2200 of work including transmission fluid, air and fuel filters, new sparks etc...
When I got it back it was fixed, and boosting with a healthy sssh on acceleration from 2200 RPM, which lasted for about 6 days and then suddenly back to poor performance or worse, and no noise from the turbo except at 6000 when high pitched whistle/whine evident. Fuel economy seems really bad - about 15MPG.
Took it back to garage for smoke test, vac test etc. but still no CEL or codes. They say it's boosting at 7psi, but that they feel a lack in performance. I guess they used a physical gauge, but I don't know how or where they took that reading.
I can't read Manifold Absolute Pressure (MAP), sadly, because I suspect a leak. Don't know if it's missing, broken, not in this model car or what. update vag-com reads it fine, must be a problem with my software.
The right hand curve below is me accelerating from 10 to 45 in 10 seconds, throttle mostly open, then foot off the accelerator. I max out at 4870rpm and 20lb! of (dashcommand estimated) boost and lambda hits .7, HP hits 97. It's supposed to be a 200 hp car :-(.
Fuel trim Long term is +5%. I don't understand how that tallies with .7 lambda. Driver information system indicates fuel economy is about 15mpg.
I don't know about cars, but turbo working, fuel trim adjusting for lean burn, good MAF... Suggests the turbo is firing up, but somehow not resulting in engine power.
Recent services: I had 2 coil packs replaced about 4-6 months ago, may be unrelated to this fault. I have not replaced the timing belt. Brakes and tires all replaced 3 months ago.
What do people suggest to fix and or diagnose? Don't want to replace the turbo if it's just a leak.
Can charge air sensor tell me a MAP that might show air leaks between the MAF and the manifold? (answer - that's the right sensor)