I wonder if anyone can help me. I have a 1990 Audi 80 1.8 that has
started making occasional strange noises but only after the engine has
been working hard(by this I mean climbing a very steep hill or
overtaking - it doesn't happen in normal commuting type driving). The
weird thing is that the noise disappears about a minute after the
engine is returned to normal revs.
The noise itself is a kind of rattling, but in some ways it's not
unlike the kind of popping and banging that you get in an old sports
car when backing off (something to do with valve overlap, I think).
I'm pretty sure that it's not that, though.
The car has done 125000 miles, but has a comprehensive service
history, and has recently had an oil change and a new exhaust. It also
doesn't burn any oil, and runs at the correct temperature.
I suspect that it might be something to do with the exhaust as it
seems to emanate from that area, but I am a bit concerned that it
might be somehing expensive, like the drivetrain or engine.
Any ideas on this would be greatly appreciated.
Thanks.

Jonathan Prestidge

 

"Jonathan prestidge" <prestidge7@hotmail.com> wrote in message
news:87306331.0306270006.684982d7@posting.google.c om...
> vwdoc1@aol.comANTISPAM (dave) wrote in message
news:<20030626201312.09323.00002020@mb-m07.aol.com>...
> > >From: prestidge7@hotmail.com (Jonathan prestidge)
> > >
> > >I wonder if anyone can help me. I have a 1990 Audi 80 1.8 that has
> > >started making occasional strange noises but only after the engine has
> > >been working hard(by this I mean climbing a very steep hill or
> > >overtaking - it doesn't happen in normal commuting type driving). The
> > >weird thing is that the noise disappears about a minute after the
> > >engine is returned to normal revs.
> > >The noise itself is a kind of rattling, but in some ways it's not
> > >unlike the kind of popping and banging that you get in an old sports
> > >car when backing off (something to do with valve overlap, I think).
> > >I'm pretty sure that it's not that, though.
> > >The car has done 125000 miles, but has a comprehensive service
> > >history, and has recently had an oil change and a new exhaust. It also
> > >doesn't burn any oil, and runs at the correct temperature.
> > >I suspect that it might be something to do with the exhaust as it
> > >seems to emanate from that area, but I am a bit concerned that it
> > >might be somehing expensive, like the drivetrain or engine.
> > >Any ideas on this would be greatly appreciated.
> > >Thanks.


This will be the 1781 golf engine, Bosch CIS-E injection I think.

Could be a weak mixture or advanced timing causing pinging.

But popping noises on overrun mean you have an exhaust leak or lean
mixture, since you've just had a new exhaust might just be a joint that
needs resealing, probably seal itself after a while...