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Re: Testing Knock Sensors

Hare,Stott wrote:
> The vehicle in question is an 84 GTI I modded for a friend in NYC.  In it I
> installed a refreshed 3A motor from an Audi 80, and the knock sensing
> harness and brain from an Audi 4k.  The knock sensing brain in question does
> have a feed line supplying manifold pressure.  Once the timing was set, it
> was possible to tap on the block and watch as the brain retarded the timing,
> incrementally if the "knocking" continued, to some "safe" spec.

Thanks for chiming in Stott, since I didn't know many particulars about
that car.  All I remember was dialing backwards while that thing headed
to zero degrees!  Kewl, as the hip young kids say these days...

> What was surprising was the base timing (initial alignment of the
> distributor) when using the knock sensing distributor and the stock ignition
> harness, was about 60 degree retarded verses when it was used with the knock
> harness and brain.  Does that agree with your memory Huw??

yup, when it was set statically to a few deg BTDC, it was showing
something like 50 degrees of advance on the timing light, and so would
barely run.  We didn't understand it but the car worked at that point...

Huw Powell


82 Audi Coupe; 84 4kq; 85 Coupe GT; 73 F250