2002 Chevrolet Corvette Z06: Work In Progress
March 03, 2010
As RC Engineering's injector flow test report suggested, the cleaned injectors made little improvement once reinstalled.
Keep in mind that if the detonation had gone away as a result of this, it still wouldn't explain why the ECU refuses to recognize any knock activity. Even physically rapping the block doesn't register knocksum on the scan tool.
This is really the oddest part of the Z06's knock situation. As I mentioned earlier, there are no readiness codes, no DTCs, no knocksum -- absolutely nothing anomalous according to the ECU. It thinks everything is just awesome even as the engine pings audibly.
Aware of this, Bothwell was planning on scoping the knock circuit while the injectors were out at RC, but he became deathly ill and was home sick those days. So he's doing that electron work today along with cleaning and checking the MAF in an effort to bring the fuel trims down to a more reasonable level. This fuel trim activity is separate from the knock detection/correction thing above, but the former isn't helping given the latter's current situation.
As for intake leaks allowing in unmetered air, we found none while reassembling the intake when we performed the TSB.
A word on the local Corvette specialists, since you asked: one of them doesn't service cars anymore, another took four days to respond to our inquiry, another was actually a Chevy dealer and not a specialist like we were led to believe, and the last one only does basic routine maintenance.
Jason Kavanagh, Engineering Editor