So I'm helping my friend out with his car and apparently the battery isn't charging as we found out the hard way. Basically I'm throwing him my old 60amp alt since I did the 80amp swap awhile back. Unfortunately his entire harness got torched in a fuel fire and so I'm trying to figure out where I need to plug the 2 leads on the back of the alternator into. We wound up getting a 4 lead ford voltage regulator and so i'm thinking that should work, of course we really aren't concerned about the dash light. Box for the regulator says BWD P-Series R400P if that helps any.

 

If you have two spots in the back of your alternator; it is internally regulated.

 

Yeah I'm stupid. I just noticed that when I got the alternator back in hand.

Any idea what lead needs to go to where so I don't have to worry about overcharging the battery? Mind I have no idea which wire would lead to the dash in the bay since the whole harness torched up.

 

Putting it another way I just dont know which lead is the field and which is the sense because the only letter marking is an L. If anyone knows which is which I can probably take it from there.

 

Where did this alternator come from? And what car is it going into?

Plug up one to a pos power source. Run the engine; if it works there's the wire your looking for. If not plug the other wire up. You can use any 12 volt pos power source, but you might want to use one that turns on when the ign is on.

 

It came out of my 83 gs and is going into my friends 88. Obviously his is a 2nd gen and he didn't listen to me about the pulsation damper and so blah blah blah engine fire. Torched the whole harness so I swapped in a racing beat holley for him and he just had the exhaust done so all thats left is this alternator charging problem.

I'm new to alternator wiring so I'm not sure about all of this but I think the main wire goes straight to the battery to charge it, it uses the engine as a ground, and as for the lead with the "L" stamped right over it I think I just need to jumper that to the charging lead. This leaves me with just 1 lead left that I have no idea what to do with or if it's even necessary. A few things I've been reading state that it's a backup for the charge light while other things say its for the PWM, and others say its for the ignition as a turn on point.

Been reading this MOTOR Magazine Article | MOTOR Information Systems and the last paragraph of the "Then and Now" section has me all over the place.

As much as I would like to turn it on to test, I don't wanna **** my neighbors off tonight. Sure it smokes a bit on startup but that new exhaust may as well not even be on the car <.< so damn loud.

Edit: Another funny thing of note is that since cutting out the harness I fixed his ignition with the same GM ignitor mod that was suggested as a replacement for our j109s and switched him over to a 1st gen dizzy. just for lulz

 

Ahh... nice read

I've never paid any attention to the letters.

I or L will work acording to this guy.

hehe diesel tac signals come from the alternator

 

Well tried the jumper idea and the second I reconnected the battery it sparked and blew the 80amp main fuse. Just kill me already.

If anyone has ANY idea what I should do then please, feel free to tell me. I'm at the end of my rope with this. It will be much appreciated.

 

Jumper idea?

I can tell you exactly where to plug up an alternator on an SA, but I don't know jack about FC's. This might be a better topic for that forum.


You have your alternator with the large nut attached to a nice thick wire running to the pos battery post right?
And the little wire that plugs into the back of the alternator is pluged into the alternator slot right?

 

Normally I would agree but since I'm transplanting an FB alternator into an FC and there is no wiring harness it really shouldn't make a difference.