what could this be? slow acceleration, no uuumph, no other symptoms

Discussion in 'Audi TDI forums' started by aoleks, Oct 19, 2017.

  1. aoleks

    aoleks New Member

    Aug 26, 2016
    Audi A4 B8 2008 2.0 TDI CR
    London, UK
    audi a4 b8 2008 2.0tdi caga (143hp)

    alright, I just got another issue with my car... things never seem to end, I'm starting to consider another car. a brand that's not rubbish after 8 years...

    anyway, car drives super smooth (almost like a brand new one), fuel consumption is very good, no vibrations or noises. however, it seems like I'm driving an engine without a turbo. no engine malfunction light (will scan with VCDS later on today) but my acceleration is very sluggish. everything is linear and I barely get up to speed. feels more like an aspirated 1.2 engine. I'm guessing a shot turbo makes one hell of a noise, so I'm excluding that. it feels to me like there's no boost, but the symptoms of a wastegate stuck open are different, according to the internet.

    any clues what it might be? boost pressure sensor? N75? wastegate actuator?

  2. Ol'Rattler

    Ol'Rattler Well-Known Member

    Apr 24, 2011
    06 TDI Jetta
    Marysvile, WA.
    Probably a boost control problem. Get a Mitey Vac and check the vacuum system for leaks and proper operation of the N-75 valve and the turbo actuator. The vane plate inside the turbo can carbon up and stick even if the actuator is O.K.

    Probably many turbos have been replaced that were just fine when the real problem was boost control and/or a sticking vane plate.

    So how is your car rubbish? It's 8 years old and requires some maintenance. No rocket science there.
  3. gt4494

    gt4494 Active Member

    Jan 15, 2011
    2005 NB
    Southeast Coast on I-95. Radar detector on and yes Herbie still gets 40mpg at 80 mph
    Have you started with the simple things like making sure all the intake pipes are still connected?


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