My car is an 89 IROC with the L98. It's all stock and in good tune.
Base timing is 6 degrees with EST disconnected. Compression is 175 to 185 on all cylinders. Downloaded tuner pro rt to data log my engine and I read the following.
When I start the motor I get a knock count of 2,3, 4 or sometimes as high as 20. Nothing changes until I step full throttle into it and the knock counts climb about 1 count per every other second or so. Over a ten second wide open run I might gain 5 to 8 counts, maybe more maybe less. The timing retard graph show that no more than 4 degrees retard is applied by the computer during this event. This occurs with either a full tank of regular or premium. By my own ear I never have heard the engine knock, rattle, ping. The motor is in good shape.
The way the knock count slowly climbs I really don't think it is cylinder knock.

What do you think, is this preignition or something else?

I'm thinking my sensor is picking up the starter contacting the flywheel and calling it knock initially. The slowly increasing knock count under WOT has me confused.

Do any of you think I have a bad sensor?

Unless the run is WOT I don't get any knock count increase from the original start up count that I always get.

 

Increase your spark advance by 5* or so and do a couple more tests. If the counts don't increase then they probably have nothing to do with real spark-knock.

 

Depending upon how the attack and recovery rates are programmed, that could be completely normal. An aggressive program will constantly bump up against the EST ti tickle the knock sensor in an attempt to maintain the highest possible advance. The detonation sensor should detect knock events well before you hear them. You counts don't seem excessive. The few counts at startup are normal, as the ECM generates a test knock to determine sensor and EST functionality.

 

305,
I was thinking about trying the timing increase but only in 2 or so degree increments until something changed in the knock counts.

Vader,
Thanks for the info too! In order to remove some of the knock under WOT I have a TPIS AFPR that I was going to install and boost pressure to 48- 50 lbs. Would that increase the fuel amount or would the computer just pull back on the injector pulse width. The chip in the ECM is the factory chip.

On a side note where can I learn more about what the different data means on Tuner Pro, (BLM, integrator, etc)?

 

The computer will pull fuel back in closed-loop, but not at WOT, so it will richen your WOT operation.