A303
12-05-2010, 03:32 PM
My beloved '94 100 2.5 TDi has developed a curious problem which I would appreciate any help or suggestions on.
I recently had to have a top end rebuild when one or more of the hydraulic tappets collapsed, leading to a couple of bent valves. I forgave it this indiscretion - it has done 240,000 miles! The work was done by an Audi specialist who I trust. It had all new buckets, as well as valves as needed, plus all of the valves were lapped in.
Since then, it's suffered from an intermittent low rev 'misfire' - rough tickover, lack of power - almost as if it's missing on one cylinder. As soon as the turbo starts to come in, it flies and the problem is not always present. It seems to occur after a fast motorway/dual carriageway run when you slow down and then cures itself after a couple of miles.
I'm tending towards a fuel/air leak somewhere - possibly from a disturbed old pipe during the rebuild - but I can't find one. Does this sound like MAFF sensor or EGR valve? Any ideas or tips appreciated. Thanks.
I recently had to have a top end rebuild when one or more of the hydraulic tappets collapsed, leading to a couple of bent valves. I forgave it this indiscretion - it has done 240,000 miles! The work was done by an Audi specialist who I trust. It had all new buckets, as well as valves as needed, plus all of the valves were lapped in.
Since then, it's suffered from an intermittent low rev 'misfire' - rough tickover, lack of power - almost as if it's missing on one cylinder. As soon as the turbo starts to come in, it flies and the problem is not always present. It seems to occur after a fast motorway/dual carriageway run when you slow down and then cures itself after a couple of miles.
I'm tending towards a fuel/air leak somewhere - possibly from a disturbed old pipe during the rebuild - but I can't find one. Does this sound like MAFF sensor or EGR valve? Any ideas or tips appreciated. Thanks.