I have an 87 Turbo 2. About a month ago my alt died and i changed it. Everythign was running fine and dandy.. then a week later my car started to charge at 18 volts... so i went and got another and it was covered by warrenty... so put that one in.. then a week later its doing it again.. but it not consistant. Every now and then it'll charge up to 18 volts and then turn one i turn on something (fog lights, defroster, heater) then it'll drop back down to 12-14 volts. Does anyone know how to fix this? i have upgraded ground and powers already.. power from bat to alt... then ground from alt to batt, and batt to frame..

 

Do you have a fuse between + and the alt? If not you should. It sounds like the Voltage regulator is craping out on you. Try to search the FSM. Here is a link.

http://www.mirror.wreckedyouth.com/man/

 

make sure your not overtightening your belt. also, if youve changed alt's three times, chances are its something else, have you checked the connections at the alt its self? if they are corroded or loose or anything that can make it act wierd, i know you already said you did grounds and power but you didnt mention anything about the alt wires so im just wondering

 

A dieing battery can cause overcharging. I found this out when my aftermarket stereo quit playing. Seems it will only work at a voltage between 11-16 volts. It's a Kenwood and I was pushing 18v also. Replaced old foaming/gassing battery and everything was OK.

 

The belt tension has NOTHING to do with an overcharge situation. Undercharge could be from a loose belt, but that is all a belt could do to effect the ALT performance.

 

i already have 4awg from battery positive to alt. as well as a 4 awg from alt bracket back to the neg of the battery and from the battery negative to the frame.

 

battery is a brand new Optima Red Top... put that in after the 2nd alt dies.. which was 1 week before the 3rd one died

 

You never metioned if you have an inline fuse from the hot wire to/ from the battary to the ALT?

 

no.. i don't have a fuse inline with the wire from the alt + to the battery +

 

Anyone? This is my daily driver so i need this problem resolved ASAP

 

you should have a fuse there. https://www.rx7club.com/showthread.p...ht=alt+install check this link out it will show you how the stock configuration goes to the fues block on the drivers side strut tower.

 

Check your voltage regulator. Logical, right?

 

heres the thing that confuses me.. if the voltage regulator is shot.. then it should constantly be overcharging.. but it only does that every now and then

 

The voltage regulator is internal. Inside the ALT.

James

 

how about gague malfunction? have you gotten a chance to test it w/ a multimeter?

 

gauge is fine.. its an Autometer Cobalt volt gauge.. i know its not the gauge because when the voltage hits 18ish.. all the lights light up super bright and my heater blows like crazy