924Board.org

[isuras2]

While driving the car, under regular to hard acceleration, the car starts bucking. It happens all the time, meaning acceleration while going slow (20 mph) or fast (60-70 mph). Any suggestions?
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Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

[ideola]

Most likely, the lower charge tube bracket has gone missing and the lower charge tube is lifting off of the turbo outlet under boost.
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erstwhile owner of just about every 924 variant ever made

[isuras2]

I read this thread about checking the charge tube, but it didn't move separate from the turbo when I shook it.
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Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

[Smoothie]

Would you rate it as a light bucking, or as severe bucking?
Severe bucking - like it might throw you through the windshield if your seatbelt wasn't on, could be caused by a torn wastegate diaphragm. This allows boost to build too high, triggering the overboost cutoff switch which shuts off the fuel pumps, and you get a sudden decelleration.

Light bucking, I believe can be caused by incorrect A:F mix - too lean is it?..
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[isuras2]

I would rate it as more severe, especially under heavy acceleration. How easy it is to check the wastegate diaphragm?
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Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

[Rasta Monsta]

This could be a fuel delivery problem. . .check pump volume per FSM.

In answer to your query, you should be able to use a hand pump on the control line to actuate the wastegate (no more than 10 PSI or so), and it should hold pressure. . .forever. If it doesn't, post back for a hardware list to pull and refresh the waste. ASS! PAIN!
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3