Knock retard on 01 Corvette

[Red01Z]

The tune in my car hasn't been changed drastically in several years. However, I just removed a FAST 78MM intake manifold and ported throttle body and needed to touch up partial throttle fueling. In doing so, I disabled the MAF (fail frequency set to 0), COT, DFCO, LTFTs, and PE. In the past, I didn't usually disable PE. I was just mindful of my RPM and TPS.

Tonight I was gathering some log data doing fairly steady/gradual runs in each gear up to 4k (sometimes up to 4.5k). I noticed on a couple of occasions that the car fell on its face over 4k rpms in 4th. During these times, I was seeing KR of around 15*. Rarely have I gotten any knock retard in the 5-6 years I've been tuning on this car. I'm inclined to question whether disabling PE caused this problem to surface. My timing adjustments are pretty modest from what I've seen.

Anybody have time to take a look?

jqd091613c_knock.hpl
jqd091613-DFCO-PE-MAFc.hpt

The car as a 228/232 .585/.575 112 LSA camshaft and supporting mods (valve springs, exhaust, cai, etc.)

[SultanHassanMasTuning]

I would increase your MAX TORQUE TIMING table as your commanding more timing in your WOT tables.

your getting 14 degrees retard at 75kpa is very strange. something is off.

[Red01Z]

I would increase your MAX TORQUE TIMING table as your commanding more timing in your WOT tables.

your getting 14 degrees retard at 75kpa is very strange. something is off.

I've never made changes to the Max Torque Timing table. The help file says they recommend not changing this. Could you give me a bit more background how this could help solve my problem?

Thanks for the reply.

[Red01Z]

FWIW, I just compared my low octane timing table to that of a stock file and they are identical except in the idle cells.

[Red01Z]

bump

[Russ K]

Any knock sensor DTC's?

Russ Kemp

[Red01Z]

I didn't set any DTCs, but I just reviewed my tune and found that I had one code from the front KS disabled. If it helps, the car also falls on its face when the KR is recorded.

[Chevy406]

If the ECM sees a knock sensor failure it will pull maximum spark retard as a fail safe. You need to fix your knock sensors and then retest.