There is no audible banging or rattling, the y-pipe has plenty of clearance. The rate at which the knock counter rolls over does not change from when the engine is off vs running. I even went as far as adjusting the rockers again and there is still no change. Also replaced the sensor the other day and there was no change. I don't think this is causing a problem since there isn't any retard but it's something that I would like to figure out.


Does anyone have a good 93 pcm/ecm for sale? What should I expect to pay for one?

 

Its normal, I've tuned almost half the f-bodies around here and scanned pretty much all of them, including mine when you shut the power off you see the knock counter keep going, I've had a 93 and now I have a 95 and know they do it 100%, the engine is off not shaking anymore or anything but the counter keeps going until datamaster sees the car is off.

When you shut the car off, datamaster keeps logging and gets confused, once it realizes the engine is off, this take about 2 seconds, the graph stops moving and it stops loggin stopping the counter and all.

Matt.

 

I can agree that it happens to all / most of these cars with the engine off. In the ones that you've dealt with did the counter continue to roll when the engine was running? Mine does

 

Well, I guess I'm officially special. My gf's brother just bought a 93 Z so he brought it over to have me check it out for him. Did a little logging and burned him a base chip and never had a single problem with the knock count like you guys are describing.
Guess I'm not crazy after all.

 

I would guess in certain circumstances Datamaster hasnt properly ALDL handshaked with the PCM ... and as it polls its getting a bogus response.