Audi 80 Mk II (1991-1995) - 1992 - Pinking (Remember that ?)

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Thu 8 Nov 2007 22:57
1992 - Pinking (Remember that ?) - Alek Smart
Once a routine part of any mechanics day,this old stalwart has made a recent re-appearance in my Audi 80 (1992).
It`s a Mono-Motronic system I think and I`m at a loss to discover why the sudden onslaught of crown burning pinking.
Should I start by cleaning the Crank Position sensor.....or would the FI unit itself be at fault,,?
Have substituted several different petrol brands and garages so can rule out duff petrol.

Edited by Webmaster on 08/11/2007 at 23:17

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Thu 8 Nov 2007 23:04
Pinking (Remember that ?) - Screwloose

Checked the knock sensor? Or the timing? Has it got an ISC unit?

I'm not searching dozens of engine codes to try and figure out what engine it has.
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Fri 9 Nov 2007 20:03
Pinking (Remember that ?) - Another John H
Haynes' "Engine management and fuel injection systems manual" ISBN 1859603440 does cover the 1990-1991 Mono-motronic for a 1.8i - cat Audi 80.

Quite how much help it is may be a moot point...

You probably have a distributor, with a HALL effect sensor inside to provide base timing.
There doesn't appear to be a knock sensor.

So assuming that the timing is basically correct (the book talks about using a fault code reader on the serial port before adjusting the position of the distributor to set timing), the book suggests that "load factor" (IE timing adjustment for heavy acceleration) is determined by ECU using only throttle position and engine speed.
However, as the ECU has both air and coolant temp sensor inputs I'd bet it is considering these factors too.

IMHO your pinking is caused by any of the following:

wear in the distributor drive/chain has upset the base timing
inlet manifold leak - mixture thinner than expected
air temperature sensor fault.
coolant temperature sensor fault.
throttle body faulty

anything else I've forgotten/never knew about..

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