Issue adapting tune for new heads and cam.

[DougW]

I hate to do it, but I must now ask for help. I recently added AFR 165 heads with a Lunati Voodoo cam to my 1995 5.0 HO. Previously had the car tuned for stock except for 95 Cobra GT40 upper/lower, ported and 70mm throttle body. LU47 injectors. Tune was good and I had solved the transition to idle spark sufficiently. No stalls and great drivability.

After the new heads and cam, the engine behaves well as long as I am not in closed throttle under idle spark control. Target idle 800 RPM. Kept in O/L because of a header collector leak I need to address.

My problem is the return to idle spark control. Dashpot is ok. Idle is good and IAC duty is good with IPSIBR close to 0. Set to change to idle spark as I come to a stop at 0.5 mph. RPM hangs around 1000 -1100 RPM until stopping. Then it will either begin the surge and shut down or will just shut down.

I even tried adding some base spark (in the tune for min spark, not at distributor), as the idle really smooths out when idle control advances beyond the base 10 deg. I read through similar issues and write ups, but what am I missing on the return to idle spark control?

Doug