Question about Knock

pprice · 10-09-2009, 05:37 AM

I asked this in the C6 section by mistake, but I think this is where this question needs to be.

what year GM introduced individual cylinder knock retard?

rodj · 10-10-2009, 10:15 AM

Quote:

Originally Posted by pprice

what year GM introduced individual cylinder knock retard?

How would the ECM determine which cyl had knock?
You could only do individual cyl spark control on cars that had coil paks not a dist which all C4's have?

John Anthony · 10-10-2009, 04:03 PM

The 1987 Porsche 944 Turbo had individual cylinder knock control. The ignition was distributor and single coil.

Make the spark, listen for knock. If knock, it HAD to come from the cylinder that just fired.

Two revolutions later, when THAT cylinder is ready to fire again, software dials in the calculated knock retard for THAT cylinder.

Software keeps track of the individual retard values for each cylinder and applies them when the corresponding cylinder is about to fire.