Bambam7

What the hell- I've had so many problems with the charging system on this car. New wiring, 3 batteries and 3 alternators in 3 years.
Anyways- just put on a used alternator (an S4 actually... just had to modify the plug) It all seemed fine- exept cranking seemed a little slow if the car was sitting for a few hours. Well, tonight the car sat for about 4 hours, and was completely dead- interior lights barely glowing when the door opened. Popped the hood, and the back of the alternator was HOT.
Anyways, jumped it, and it charges just fine, but there is a discharge through the alternator. I pulled the main charging post wire off and checked for voltage between the wire and the post- and sure enough- there was 3 volts. It hardly seems enough to completely disharge a 100% car battery in 4 hours though. Very strange.
Anyone have any ideas??? Maybe take apart and clean? Arcing inside??
I do have another S5 alternator that the IC regulator went on... and then it seized from being on full voltage all the time- maybe I could salvage some parts from it to use...

Black13B

iTrader: (1)

Probably (for some reason) its still sending voltage to the regulator, which in turn.. uhh.. Really messes everything up.

3v with your DEAD battery or a new one?

Icemark

sounds like a couple of burnt rectifiying diodes in the alt.

rx-7fc

i also have a problems with my charging system also all my dash lights come on and my volts drop to 12 someting but some times when you rev it they go off and the volts go back up but sometimes the dash lights just stay on and the volts drop back down i went to test the alternator and they said it was good because i know that when the dash lights come on that means the alternator is no good have any ideas what it could be

Bambam7

Put an additionaly heavy gauge wire form the alternator to the pos terminal on the battery.


Anyways... it's 3 v with the recently jumped and charging battery (enough juice to crank over the car no problem)
That just doesn't seem enough to totally drain a battery and make the alternator hot.
Crap- I don't have another alt, and I am leaving for a 5 hour trip on Fri!!!

Black13B

iTrader: (1)

I have your alternator.

PM Me.

Entirely Rebuilt, Polished, Pulley Painted, Tested, Works Excellent. S4, so it fits your current plug. I'm selling it for cheap. Need it outta here.

Bambam7

OK- found the problem. The "R" plug- which is the IC regulator power source on the alternator is grounding out.... Strange, because it still runs just fine and the battery charges while running. The grounding is inside the alternator- not the wiring harness... now.. what to do.

Bambam7

OK- now I'm VERY confused!!! The R prong on the alt is NOT grounding out- there is NO continuity between ground and that prong! Yet there is a 12v potential difference between the "R" connector and the prong on the alternator. How is this possible???? If it's not a ground how can there be any current flow???
GUess the alternator is screwed... I'm going to have to keep it on though- I'll just unplug the plug every time I get out of the car untill i get a new alt.

Black13B

iTrader: (1)

What do you mean the R connector? I'm not sure what you mean..

Both Wires put out Signal power, neither of them are ground.

One wire (can't remember what colour) is battery charge signal in volts (tells the regulator how much power the battery has so it knows how many amps of charge to give it).

The other wire is a voltage signal less than 12v that tells the ECU / Idiot light cluster if the alternator is still alive, or if it's dead.