Gary Z

At WOT, my maximum spark advance above 5000 rpm is 19 degrees. My high octane table calls for 22 degrees. Low octane table calls for 15 or 16 degrees. I have zero knock retard and both ECT and IAT are in areas that subtact zero. I don’t have traction control. No trouble codes (DTCs). Any ideas?

foff667

iTrader: (2)

a. post your scan & editor files

b. burst knock? theres a separate pid for this

wait4me

iTrader: (10)

In Efilive you just monitor all the DMA spark pids and it will tell you the cause. Not sure how you would do it in any other software scan tool.

Gary Z

Thanks for the suggestions - I was unaware of burst knock. I need the rain to stop before I make another test run.

SikHabibBroCuz

have you got both spark tables running? (ie custom os if in SD or MAF)if so check what your knock learn factor is, if its anything less than 1 then it will pick a number between the lo and hi tables depending on how low the KLF is

PlatnumStatuz

iTrader: (6)

Hey Gary, wussup looks like you've been busy from the looks of your sig since last time I saw your car at Sears Point. I'm doing a h/c swap on my camaro right now.

SSpdDmon

iTrader: (10)

This is where my money is. Check the GM.ASPARK pid to see what it is.

Gary Z

The proximate cause of my limp timing was the Knock Learn Factor. The ultimate cause was me disabling the MAF during SD tuning which sets the KLF to zero. This appears to be the method the PCM uses to select the low octane spark table in case of MAF failure. The PCM does not fully revert to the high octane table until the KLF returns to a value of 1.0 which it does slowly. WOT timing has recovered to 21.5 degrees as the KLF has increased from 0.69 when I first checked, to 0.91 after 15-20 minutes of driving around. Thanks to all who chimed in – I learned some good stuff.

-Gary

Gary Z

Hi Brett, I’ve been scheming to squeak into the elevens. I guess you are too. Maybe we’ll get a few chances to race this season.