i managed to keep a voltmeter hooked up to it yesterday and did a test after re-attaching some missing engine grounds.

at 3600rpm approx i held it in place and it flickered back and forth rapidly between 14.5 volts and 18.5 volts, the switch off between normal and overcharging is instant, not linear it seems, don't know if that helps or not.


alternator tested good but i don't think the machine at autozone spins it fast enough to get it to do this

 

okay replaced the alternator and reconnected the ecu regulator, everything worked fine for about 30 miles, then the alternator blew the field coil.

i do not know why.