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Audi A3 1.6 AVU 2000 - Unusual throttle control problem #

Posted by Christopher Taylor on March 9, 2009, 6:27 pm

Year of Manufacture *: 2000
Engine Code or Type *: 1600cc, AVU Engine
( Optional ) ECU Type: Simos 3
( Optional ) Scanner used: Vagcom, Bosch KTS.

This Audi has failed the MOT emission test because once the engine is hot it becomes impossible to hold the engine revs at the correct speed. As you press the pedal the revs increase upto 1200 rpm at which point they shoot up to 4200 rpm. When you back off they instantly drop off to just above idle.
It came to me with a dirty throttlebody and a few split breather hoses. After these repairs I reinitialized the throttlebody, roadtested and rechecked.
It generates no fault codes, drives very well, the emisions at idle are spot on. I can find no air leaks or faults with the engine condition, engine management, ignition or emissions.
I remember some Fiats suffering from a similar problem which was a software issue. Before I give up and refer the customer to the dealer has anyone any previous experience with this fault?

Re: Audi A3, Unusual Throttle control problem.

Posted by John Ritchie <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2638' width='330' height='300' border=0 style='border:none;'> on March 9, 2009, 7:11 pm, in reply to "Audi A3, Unusual Throttle control problem."
John Ritchie

Hi Christopher , don't think this was relevant to Audi but jack up a front wheel and see how idle behaves for mot .. not a fix but worth a try

regards
John

Re: Audi A3, Unusual Throttle control problem.

Posted by Nigel Bennett <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5463' width='330' height='300' border=0 style='border:none;'> on March 9, 2009, 10:05 pm, in reply to "Re: Audi A3, Unusual Throttle control problem."
Nigel Bennett

Carry out throttle body adaptions!

Re: Audi A3, Unusual Throttle control problem.

Posted by Martin Tribe <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1173' width='330' height='300' border=0 style='border:none;'> on March 9, 2009, 10:26 pm, in reply to "Re: Audi A3, Unusual Throttle control problem."
Martin Tribe

Check your MOT testers manual, if I remember correctly there is a different fast idle test speed for this engine code because as you say it can't be held at a constant speed.

Re: Audi A3, Unusual Throttle control problem.

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on March 10, 2009, 9:47 pm, in reply to "Re: Audi A3, Unusual Throttle control problem."
Ian Staples

Hiya

Dont know if this is the cure, but i had a VW recently with similar problems, live data showed the supply voltage going all over the place between 4v and 14v. After a bit of supply checking at the ECU multiplug and following a wiring chart i found one of the ECU supply lines varying between 4v and 14v with all the others at 14v, turned out to be the ECU relay at fault.

Re: Audi A3, Unusual Throttle control problem."Solution"

Posted by Christopher Taylor <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5137' width='330' height='300' border=0 style='border:none;'> on March 12, 2009, 3:40 pm, in reply to "Re: Audi A3, Unusual Throttle control problem."
Christopher Taylor

Thankyou for all replies. Jacking wheels up made no difference and all supplies to the ECU checked out OK.
As suggested when I checked in an old MOT testers manual this car has a very high rev window of 4300-4800 rpm. It and the Golf with the same engine code are unusual in this.
So turns out to have nothing wrong with it!

Thanks

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