GrannySShifting

iTrader: (10)

Going thru alt, still having issues. Original issue was car kept dropping voltage under WOT load on dyno. WOuld hold steady 14.1 volts, then started dropping to battery voltage for a split secodn then recover to 14.1. It progressively got worse some pulls it would drop to battery voltage right away, sometimes it would drop then midway thru pull then recover. Went thru 3 alternators doing different but similair stuff. Tried volt booster and it would hold at 15.5 for a minute, then started up/down stuff again. Tried sending alt out have it rebuilt, 145 amp in stock case (same person that did KPs and he had no issue for a few years of racing with a volt booster)

First pull 14.1 volts, hit WOT, volt booster did its job 16.4 volts dead rock steady. Thought we were back in business. Next pull it wavered around 16.2 volts +- .5 volts. Pull after that, held at 16, dropped to 14 gradually, midway thru jumped back to 16 v. Each pull getting more and more erratic.

Any ideas?

fasttagurl

iTrader: (12)

Check the alternator wire and make sure it's not broken or burned. Mine recently had this same problem and we found the wire had broken off the black plug-in sensor that goes into the alt. We fixed and no issues since.

GrannySShifting

iTrader: (10)

Replacing the pigtail is the first thing we did

Lickeyman

iTrader: (1)

I'd run a charge line straight from the alt to the battery and then slap new grounds on the battery and motor.

Battery hasn't been relocated has it?

edcmat-l1

iTrader: (10)

Try monitoring the exciter wire with a volt meter.

I had one a couple years ago that would kill the alternator after a couple WOT pulls. Eventually we got one that didn't **** the bed. I guess in that case they just couldn't take the RPM.

GrannySShifting

iTrader: (10)

Switched 12v to the exciter wire, and does the exact same thing. Any other ideas?

cablebandit

iTrader: (37)

mine had a smaller pulley on the alternator and would slip......at track especially 1-2 gear but better in 3rd

GrannySShifting

iTrader: (10)

tried new stock size pulley, manual tensoner, new belt, lots of tension. dont think its intermittently slipping

tarinitup

iTrader: (11)

Ever figure this out? My truck loses voltage and goes to battery at wot under load aswell but is normal all other times.