Charging system not working?

[Mercracer]

Starters might spin fine out of the car, but when hot it might be tired and not have enough oomph to crank over the engine.

That is one reason I recommend driving the car in to be tested. Your starter draw can be measured while it is on the car. You will also get an amp draw reading with the engine off.

[gadget73]

Good point. My starter was getting intermittant and it was just worn. It wouldn't get weak, just it would do squat. Tap with a hammer and it would come back to life.

[Mercmarquis]

Well I just got back from a family reunion. Needless to say it was boring. But I saw a potiac lemans GTO clone for $2100 with a 455 which I almost considerd selling my POS merk for. So I decided to work on my car. Here is what I found out. I jump started the car and checked the timing. After that I got in the car and noticed the interior lights are real dim and my radio wont even work. Which leads me to think my car is running off the battery alone and not getting charged by the alternator. But last monday when i drove it the car, it started and the radio, lights ect.. all worked awesome. Then on tuesday I ran it out to work, where it worked fine like the night before, When I was leaving work the car seemed slow to start it, and when i got home the motor would not crank over, and I havent drove it since. This might be because my battery was charged all up. Now if my battery, alternator, voltage regulator, and timing all test fine, what could be the culprit? I dont think there is any draw, on account of that the car doesnt lose its charge when its off. This all happens when I get to my destination and turn it off and immiediatly try to start it. If anyone has a wiring diagram for the charging system I can clean and check all of the connections and stuff. Long post eh...

[Mercmarquis]

Oh and I would drive it to be tested but my nearest autozone is like 20-25 miles away and since the car stalls once in a while I dont want to find out that my car wont start on the middle of route 6. I'll have to call napa and see if they will do it. If not what kind of meter should I buy to test it myself?

[TommyN]

Don't you have a parts car? Maybe swap the starter from the other car.

What year was the Pontiac?

Tom

[Mercmarquis]

The starter on the other is wasted. That little cover was rusted out and you had to beat it with a hammer sometimes. The poncho was a 72 lemans GTO clone I guess. It was in rough shape as it had no rear bumper and the quarters were bondoed. The paint was nasty orange peel black.

[gadget73]

a voltmeter is all you need. At idle, voltage should be 13.5 - 14.5, and usually it will climb just a little with throttle. It should settle out around 14.0 volts. Lower means the alternator or VR isn't working, higher means the VR is shot. If the parts test out OK (how did they test them not on the car anyway? these things really should be tested in place to get an accurate analysis) then check the fuse links over by the starter relay. I'm not sure which ones are for the charging system, but on my car there are two on decently fat (10 or 12 ga wire) that run from the relay, around the front of the radiator behind the header panel and over to the alternator. If you aren't sure if they are good, disconect the heavy wires from the alternator, and just stick a test light on them. If the bulb lights, the fuse links are OK. Also check the condition of those alternator wires. Mine were melted and the thing was just about charging.

[Mercmarquis]

They test the stuff out of the car with a dyno like machine for alternators. They hook up wires to the back of the alt leading to a gauge, and for the voltage regulator I guess they run current through it to see if that works.

[Mercmarquis]

I got a multimeter today and I checked the fuse links by the starter relay and they are OK. Then I tried to test the alt on the car but nothing works. I grounded the - on the core support and touched each heavy wire and got nothing. I am not sure if I did it right though. Any ideas anyone?
Also I set the timing at 10 BTC should I try 8 or 6 degrees?

[gadget73]

10 BTDC with the SPOUT unplugged. Retarding it from that point might also make it hard starting. It'll require a fair amount of extra cranking for sure.

core support? just check the voltage directly across the battery terminals. The other thing I'm thinking it could be is the ignition switch. I know somehow there is a connection in the ignition switch to the voltage regulator to switch it on. If the ignition switch is failing/failed, it might not be turning the regulator on. I don't know which wire in the sytem goes to the switch tho, so maybe if someone has an electrical diagram for an 85 they could help you out with that. Fords were known for having faulty switches, so who knows. It seems they do really funky random things when those switches start to go bad.

[Mercmarquis]

I'll keep that in mind but I cleaned every connection and charged the battery and checked all of the fuseable links and it seems to work fine for now, but who knows?

[Chachi]

i had the same problem with my car last month. the alt. was not turning on. but it was still good. i did find that a wire on the drivers side inner fender was caroded and came loose from the gray harness plug. so you should visualy check the wiring

[Mercmarquis]

Yep, I checked all the connections and replaced some nasty wires with new ones. I've been running it for a week with no problems, so I am happy :banana: