I just got my FD alternator with dual pulley yesterday, put it in the car yesterday. At idle i'm anywhere from 12.5-14.2ish volts. But late tonight i was driving the car semi-hard, noticed all idiot lights came on in the dash anywhere over 4000 rpm, and went out again at about 6500 rpm.

I took a look down at my sunpro volt gauge, and i was between 15 and 16.5 volts!!!! Seems like it could be a bad regulator to me, but i want to rule out all other possibilites first. Could it be faulty wiring to the alternator? I guess I'll have to backprobe it tomorrow. Sigh.

BTW i'm running an almost new Optima Redtop, and the alternator that came out of the car i suspect had a bad voltage regulator as well, because i needed to rev the car to 3800 rpm at startup to get it to start charging.

 

yeah. just read this thread https://www.rx7club.com/showthread.p...=over+charging

I'm definately gonna drive it under 3k rpm to work tomorrow, and then backprobe the alternator connector. maybe put the other connector on it? i'll let you guys know what i find.

 

anybody? searching i'm finding tons of undercharging problems, and the ones that are about overcharging don't really apply to my situation

 

Is this an S5 or S4? S5 should be plug-n-play with the FD alt (wiring wise). My thoughts are:

- the S terminal on the back of the alt is not getting power. That is the 'sense' terminal. The alt adjusts its output based on the voltage there. If it is not connected, the alt will think that there is a huge drain on the electrical system and will start charging at full output

- if the S terminal is getting the correct voltage, I would suspect the regulator. Take it to autozone or similar and get the alt tested. If you have a local starter/alt repair shop, I'm sure they could replace your regulator and rebuild your alt for not too much money (I had an S5 alt done like that for about $70).

 

update: tested the alt when i got to work this morning, first checked values at terminals S and L, all were within spec. then tested the alt... alt tested bad on the diodes AND the regulator. So i got it rebuilt this afternoon, just finished putting it in. Running at 14.5 volts across the board now