I have a 1999 C5 Corvette FRC with a 427 cubic inch engine and twin Precision 6265 turbos. Yesterday at the track, it went into REP mode on 3 out of 10 passes. It happens during launch when trying to get more aggressive than a 1.5x 60 foot. The car has the potential to go low 9s with the 6 speed transmission if I could launch it more aggressively, but getting aggressive with the boost controller and trying to apply the throttle quickly results in an aborted pass and spending your time going down the track at 25 mph. It's not very fun when the event is being broadcast online and it looks like the car can't get out of its own way. I told people I was trying to tune around it with HPTuners and they just scratched their head.
I have attached the tune file. I'll upload all (3) log files later this afternoon from when it went into REP mode. The tune is scaled 50% and I've maxed out all of the tables that I know of to change. The combo spools very quickly. There is no 2-step, but it is at 19.2 psi by 18 mph and 44 lb/min at 24 mph.
Please take a look at the tune and let me know if there is anything I have overlooked.
current tune used on 4th pass with rep and ve changes.hpt
*Important Info*
This is the code I am getting:
DTC P1515 Control Module Throttle Actuator Position Performance
Circuit Description
The commanded throttle position (based on accelerator pedal position and possibly other limiting factors) is compared to the Actual throttle position. The 2 values should be within a calibrated range of each other. Both the PCM and the TAC module redundantly monitor the Commanded and Actual throttle position. This DTC sets if the PCM detects the problem.
So:
DTC sets if the "PCM detects the problem". The PCM and TAC module monitor Commanded and Actual Throttle Position, but the PCM sets the DTC. These two values need to be within a calibrated range.
Would the calibration parameters be in the PCM?