Greetings,

Prepare for a TLDR post.

04 Grand Prix
Engine: Fully built, the only thing stock in this engine is the crank and Cam bearings.
Fuel: E-85, 16Gal Fuel cell, -8AN lines fed into 2 300LPH pumps, -6AN return into a Fuel Lab FPR.
Electrical: Mechman 240amp Alternator. The following is all 0 gauge: Positive post to Fuse box, Alt. charging post to fuse box, Negative post to body/frame, Negative post to alt. Bracket. Finally an 8 Gauge wire going to pumps

My issue:
While driving and let off the peddle, anything below 35mph my voltage will drop to 12.0-12.5, the pumps will drop, fuel will fluctuate between 14.0 and 15.5 and the RPMs will drop to 500-600. It will stay at a low voltage state for over 5 seconds until it goes back to a normal 15V. I can tap the pedal for it to go back up also but will fluctuate for about a second.

Resolution Attempts:
While scanning I noticed my Timing drops to 15* but no table references this except a maximum knock retard table, but that does not affect when changed.
I manually commanded to 25* of timing, although the timing doesn't drop, the voltage and RPM do.
I changed the normal spark tables at idle to 35* and also 45*, but that did not help. Actually my car can't even get up to 30* at idle.

I was told that the alternator has a feature that could be causing this, but I have no idea. I know my PCM is missing a lot of parameters that will only be added upon request and proof that it is supported. Does anybody have an idea that could possibly help resolve this issue? Can anything in the tune help this? Am I completely boned and have to deal with this stupid alternator feature?

ve tuning.hpt
voltage drop.hpl
maximum and set 25.hpl