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  1. #1
    Active Member One Ring socom458's Avatar
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    2010 A5 2.0 hesitation and stumble under light acceleration - need help reading logs

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    Hello, looking for help on what to log with vag-com for a hesitation and intermittent fumble issue at 2500-3000 rpm under light acceleration. I have searched and read dozens of posts, but still am not sure how to get actual data to define next steps.

    hesitation is constant on any slow acceleration, WOT masks the issue, but still there. Stumble is intermittent at the same time (in conjunction with hesitation), and feels like a quick misfire. When the stumble happens, if my windows are up and radio off, etc. I can hear the turbo and it sounds like it spools up, lets off, spools up, lets off, etc. like the wastegate is opening or something. I have no codes, no CEL. New to the 2.0, came from a B6 1.8t. Have limited VAG knowledge, but can follow directions. I am never sure how to read the logs. attached is a log of actual vs requested boost, not sure why actual is higher than requested, but i guess there is some atmospheric value i need to subtract.

    Things i have done recently(just acquired this used car). New plugs, coils (red top). New front O2 sensor, new MAF, New PCV, later replaced with 034Motorsport PCV\Catch Can kit, Go Fast bits diverter kit, New A\C pressure switch,New N75 valve.
    Audi dealership 90,000 scheduled maintenance, with BG induction cleaning (some cleaner in a can for injectors, not intake removal and valve scrub)

    Car idles perfectly, needle never bounces.

    Any ideas on what to log with Vag to help narrow the search?


    graph from VAG logs: https://drive.google.com/file/d/10JN...ew?usp=sharing
    raw data in ods format (open office): https://drive.google.com/open?id=18_...HFftwhogmIHUeA
    Last edited by socom458; 08-08-2018 at 07:21 PM. Reason: details added
    Central Ohio
    2010 Audi A5 2.0

  2. #2
    Active Member One Ring socom458's Avatar
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    Central Ohio, United States

    anyone have a good starting point for things to log with vag-com for this type of issue?
    Central Ohio
    2010 Audi A5 2.0

  3. #3
    Active Member One Ring socom458's Avatar
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    figured out the issue, since this post got a couple views, thought i would post the issue. Pulled front O2 sensor and ran a $20 android bluetooth camera(scope) inside to look at the back of the turbo. Turbo wastegate is not seating well at all, in fact probably 1/8 " or more open at rest. I tested the linkage\actuator rod originally, and found no movement along the length of the rod (from front of car to back of car motion). This time i did notice quite a bit of slop jiggling from driver side to passenger side motion. Camera confirms waste gate is hanging open, and jiggles around.

    Currently making calls to see if my AUL aftermarket extend warranty will handle it. According to the docs, the factory turbo and all internals are covered, just getting approval to take it to the audi dealership for diagnosis.

    will update after progress is made.
    Central Ohio
    2010 Audi A5 2.0

  4. #4
    Established Member Four Rings wkhanna's Avatar
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    just saw your post, socom...

    this is xlent info!!!!
    i love the trick you used to scope the waste gate....

    were you ever getting a CEL?
    specifically the 0299....

    can give a link for the scope you used???
    Bill

    Practicing Curmudgeon & Audio Snob

    2011 A5 2.0T Old Man Project
    2011 A4 quattro 2.0t (The Wife's)
    1983 Porsche 944 (Modified)
    1985 BWM K100RS (since new - Heavily Modified)
    1971 Moto Guzzi Elderodo
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  5. #5
    Active Member One Ring socom458's Avatar
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    Quote Originally Posted by wkhanna View Post
    just saw your post, socom...

    this is xlent info!!!!
    i love the trick you used to scope the waste gate....

    were you ever getting a CEL?
    specifically the 0299....

    can give a link for the scope you used???

    Hi, funny thing is, i kind of suspected the wastegate, as I had the same problem on my A4 B6. I just didn't feel like dropping the exhaust to have a look. I was swapping the front O2 sensor, and it just hit me.......... you get a pretty nice view of the wastegate and turbo fan.

    I never get a CEL, i believe you have to have a difference of 10psi between requested vs actual boost (i got this info from my old tuner on the A4 B6, so may not be applicable here)

    any of the scopes should work, i got this one, but it was on the clearance row and was like $20 or something..
    http://www.microcenter.com/product/5...doscope-camera


    just your basic wifi android scope with light. very handy.. also used it to find the head gasket leak on the back side of my landrover engine!

    Hope it helps. I have an appt. on 8/15 with the dealership to see if i can get it replaced under an aftermarket warranty program.


    also, if you happen to have any software (vagcom or OBDEleven, Torque) log requested boost vs actual boost. I compared my old logs from the A4 (same issue) with the A5. When you upload the logs to: http://log.malonetuning.com/upload the telltale sign is the boost curve is right on(graphically), but actual boost is lower than requested. The curve looks good, matches up, etc.. just lower number across the board on actual boost.
    Last edited by socom458; 08-13-2018 at 07:59 PM.
    Central Ohio
    2010 Audi A5 2.0

  6. #6
    Established Member Four Rings wkhanna's Avatar
    Join Date
    May 12 2017
    AZ Member #
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    My Garage
    needs cleaned
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    Land of Archaic Anachronisms

    that is a fantastic source of data you linked us to.... thank you!!!!
    Bill

    Practicing Curmudgeon & Audio Snob

    2011 A5 2.0T Old Man Project
    2011 A4 quattro 2.0t (The Wife's)
    1983 Porsche 944 (Modified)
    1985 BWM K100RS (since new - Heavily Modified)
    1971 Moto Guzzi Elderodo
    Avatar Chart



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