Audi A4 Avant - Lack of engine performance

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Sat 4 Jun 2011 16:15
Audi A4 Avant - Lack of engine performance - npwebster

Help! I have a 97 Audi A4 1.9tdi with a lack of turbo boost above 2000rpm, the ecu is showing no fault codes and the only other symptom is on start up the engine revs to 2000 rpm before returning to idle at 900. I have repaced the air mass sensor but to no avail next port of call was the N75 sensor but not sure if i'm going in the right direction?

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Sat 4 Jun 2011 16:21
Audi A4 Avant - Lack of engine performance - injection doc

check all the vacum pipes for splits or cracks to the actuator on the turbo and make sure the waste gate control is free

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Sun 5 Jun 2011 15:07
Audi A4 Avant - Lack of engine performance - npwebster

Waste gate has free and full movement the pipes all seam ok . Having looked again the overrev on start up is follwed by the wateagte opening (assumption - wastegate vacum solenoid fully closed position? occuring at 2000rpm) then revs drop back to 900. Can anyone advise on how much vacuum should be present at idle?

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Mon 6 Jun 2011 15:36
Audi A4 Avant - Lack of engine performance - optional.extra

The over rev on start up may indicate a possible fault with the temp sender - this does not always get logged as a readable fault .

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