My alternator is not charging. It is a good alternator. I wasn't getting power to the field wire of the alternator, so I spliced into it before the plug and ran a wire straight to the battery. Now the volt gauge reads about twelve volts with the engine running. I am getting just under twelve volts from the battery when I checked it with a meter while running. From what I understand I should be getting from 13-15 volts at the battery with the engine running, correct? What could be causing no power to the field wire? Any ideas on why i'm getting less than 12 volts with the engine running?

Thanks

Oh yea, 87 IROC 305 TBI with a 5 speed tranny.

 

Couple of questions here since you say it is a 87 Iroc with a 305 TBI 5 speed.

1. is that the original engine since there was not a 305 TBI for that year?

2. How many wires are in your connector at the alternator and is that the correct alternator for that engine (car)?

3. Have you checked all the fusible links?

 

Excuse me...TPI...miss type.

There are 3 wires on the plug and one going to the post on the back of the alternator.

The fuseable link between the battery and alternator is good. Where might I find the link between the stater selenoid and the alternator, is it easy to get to or do I have to crawl under the car and check it?

And which fuse does the field wire run through, is it in the fuse block, and if so which one is it, my haynes manual says "FP Fan Fuse 20A" I'm guessing that FP is fuel pump.


I think the voltage is right, I checked another car that I know is charging right and the meter I was using read low also, it is just a cheap meter from wally world.

Thanks for your help.

 

Okay, you're excused!!!!!!!!! On your car if there has been no modifications to the alternator wiring than the one you mentioned. There should be three wires in the connector going to the alternator plus a black/red wire going to the alternator from the battery through a fusible link. On the three wires going to the connector the wires are as follows.

Pin "L" is a brown wire going to the voltage guage on the instrument panel and becomes a pink/black wire going to the Gages fuse.

Pin "F" is also a brown wire going to the "FP-FAN" fuse.

Pin "S" is a red wire going to a fusible link down at the starter solenoid.

The "FP-FAN" is only for the fan, the fuel pump doesn't have a fuse in your car other than the 20 AMP fuse located near the battery in the engine compartment and the two fuses for the injectors.

 

ok, i'll check that in the morning, I was editing my post cause I forgot to put some stuff.

Thanks man.