01 Galant Not Charging Correctly

Ive got a 2001 Galant 4 cylinder that I am racing. We have tried 2 different alternators and have had both tested at the parts store and both bench tested good. ive got a small tested that has 3 lights for the battery and 3 for the alternator…all of the lights light up on my truck when I tried but when I hook it to the race car I only get the 3 battery lights to light up so its not even seeing the alternator. I cleaned the grounds but that didnt do anything. Anyone have any other ideas I can try?

If your car has a battery warning light in the dash then check to make sure it is working when you turn the ignition on. The circuit supplies power to the exciter inside the alternator. If power doesn’t get to the exciter then you get no charging action from the alternator.

There is no dash in the car as it is a race car…there are no guages or anything.

Have you checked the fuses? Make sure they are ok. The ‘L’ lead on the back of the alternator needs to have power getting to it when the ignition is turned on.

Cougar is correct on all points. Unless the fields in the alt. are excited it will never charge.

To do a quick test turn the key on and touch a screwdriver tip to the alternator pulley. You will likely find that the pulley is not magnetic.
Wire a power source into that alt. to excite the fields and repeat this test. Odds are you will find that the screwdriver tip will stick to the pulley.

Im not the mechanic just the driver but I am trying to learn…what is the ‘L’ lead?

Have you checked the integrity of the starter and battery cables?

car starts fine each time we put a fully charged battery in the car but we let it run for 5 minutes and it wont start again. I was told before that if you start the car and take the positive cable off and it stays running its not the alternator but if it does then it is…well I did that and the car stopped running.

The problem is not the alternator. It’s the lack of an exciter circuit. This should be a five minute fix.

How do I go about fixing it?

Have the Alt circuit wired properly.

I popped the fuse box cover off under the hood and there are 2 that show pictures of a bteery…they arent actually labeled with words…one has the relay but the other is empty…is it possible that is the cause? I didnt take them out so I am not sure what happened to them. Also it doesnt say what kind of relay/fuse to put in it…if anyone can help or get the information it is missing relay K under the hood and there is a picture of a battery on the fuse cover. If you can tell me if that will fix my problem and what kind/amps to get that would be great. Would the parts store be able to help me if I just brought the fuse box cover in and told them I need that one?

The L lead on the back of the alternator is the lamp lead. This is the warning light lead that normally ties to the light in the dash that turns on when the alternator is having trouble. Power from the ignition switch is tied to one side of the light and the other side of the light then ties to the L lead connection. This forms a series circuit that supplies voltage to the exciter field inside the alternator. You can do a web search to learn how alternators work. There is plenty of info out there you can access.