Pinking hunting and random rev increases

[seawall]

Just joined, so here's my poser for the day. Tuesday last and the car (Audi 100 2.0 E estate) will barely drag itself up the slightest hill. I got it to work and we had a look under the bonnet. Problem was a timing belt like a rubber band ( ooops!). This was changed along with the tensioner by a garage on the trading estate where I work. they had a slight problem sorting out the timing - i think it might have jumped a tooth. when they gave it back they mentioned that it was pinking badly, and bloody hell weren't they right. this manifests itself when the car has warmed up and is under load eg Telegraph Hill on the A380. They declined to do anymore work on it, suggesting that it was 'not adjustable'.

The following day two more exciting things occurred. Firstly, bowling along at a speed slightly above the national limit I felt that the car was actually accelerating itself. On a downhill stretch I knocked it out of gear and the revs climbed to 5000 before I re-engaged a gear to drag it down again.

Shortly after, I joined the tail of a queue of traffic to find that the engine was 'hunting' in an old fashioned diesel kind of way. quite impressive for a petrol. On trying to move forward slowly in the traffic, the hunting manifested itself as a prolonged series of learner driver kangaroo hops, shaking me around and upsetting the guy behind me who gave me loads of space.

This only resolved itself when I shot into a lay-by, anchored up and switched off for a while to calm down.

The advice that I have been given so far suggests a possible ISV fault, which has been exposed by the nice new taut timing belt. Any other advice welcome.

Thanks for looking at this post.

[Crasher]

Sounds like the ignition timing is out, what is the year and engine code?

[seawall]

1994 on an L plate, appears to be ABK. I think they set the ignition timing 18 degrees before TDC, but they may had had issues with the engine timing as I think they had 2 goes at it. They certainly aren't cowboys, but I don't think they do a lot of Audis, sadly.

[Crasher]

Well that is your problem. The ignition timing is set using diagnostic equipment such as VAG-COM in basic adjustment mode 04, main group 000 and set at between 2000 and 2500 rpm at 6 degrees BTDC.

[seawall]

Thanks for that. I'll pass this on to them. Otherwise, off to another garage..

[Crasher]

Don't leave it long or you will burn out a piston or the head gasket between two cylinders, usually between one and two.

[seawall]

All sorted now, thank you for the advice and assistance.