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low power A4 2.5 tdi

wavey-davey Jun 19, 2009

  1. wavey-davey

    wavey-davey New Member

    hi im looking for some help- i have a 2000 A4 2.5 tdi quattro avant engine code AFB. it seems to be very low on power but its not "limp mode" as i have another car which does this and is very definite. i can hear the turbo spinning it just feels very sluggish. sometimes you can feel through the accelerator it almost wants to take off and give full power but is holding back.ive swapped from another car the same:MAF sensor,N75 valve, intercooler sensor.but it made no difference. no codes are logged on the ECU. Also the fuel consumption is pretty bad 18-20 mpg. dont know if its related but the coolant temperature dial sits around 70-75 degrees but i thought it should be 90.any help is much appreciated as ive gone through the forums and tried most things
  2. quattrojames

    quattrojames Moderator Staff Member Moderator Audi A6 Audi Avant Owner Group

    Hi davey

    Have you had the car scanned for fault codes? Thats got to be a priority rather than try and make random guesses. The running temperature can't be helping things.

    Have you checked the turbo isn't sooted up? How many miles?
  3. JST_A3

    JST_A3 Member

    You could try changing the temperature sensor as it's reporting a low engine reading to the ECU and this may affect the power. Perhaps the engine limits the power/torque until it's fully warmed up?
  4. olds_kool

    olds_kool Active Member VCDS Map User

    the vnt turbo on these can coke up, its fairly easy to remove and de coke it and taking hot side apart to clean doesnt affect balance so its worth trying
    mine was sluggish untill i cleaned it now goes like a rocket
    mine didnt have any fault codes logged either
    with temp sounds more like thermostat than sensor, belts off job!!
  5. Turkster

    Turkster Bro.Paul 2.5TDI Quattro Sport

    the water temp could be the fault of the sensor. real easy to fix, cost about £30, if that fails then it could well be the thermostat being in the open position and not closing fully, my 2.5 had that issue,

    the thermostat is positioned behind the cam belt :ermm: so its cam belt off to change that part, and then there is the water pump, which is a cam belt off job too,

    so if the temp sensor don't fix the issue then buy your self a new cam belt kit and get stuck in, or find a volunteer to do it for you,

    so if your water temp sensor is not giving the right reading then the cars ecu wont be telling the rest of the car what to do,
  6. wavey-davey

    wavey-davey New Member

    ok, still have the low power problem but ive had it along a diagnostic company.he says there are no fault codes logged. He says when taking readings while the car is running the turbo is working ok, but the MAF is not getting enough airflow?? through it. ive tried a MAF off another car the same and it made no difference. hes checked the voltage from the MAF signal wire and its reading correctly. ive tried blanking off the EGR inlet pipe- made no difference. ANY IDEAS????

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