steele

Ok, this is for my roommate's '88 Firebird which I've put in my sig.
He's had the car about a month with no problems. Car needs work here and there, but it runs & drives fine other than the loose steering which I plan to help him fix soon.

Anyway, he tried to start the car after letting it sit in the garage over the weekend. Car is so dead, not even a light will come on. I assumed the interior light had been left on by accident. Jumped his car and it ran fine. He ran it awhile to let the battery charge up, and the car started fine when he went to work this morning. Started again when he was leaving work, but when he tried starting the car again after a 10 minute stop at the store, it just clicked. I drove to the store to give him a jump, but this time no good. Couldn't figure out what was wrong, but I tried taking the neg end of the cable off the frame of his car and putting it on the neg battery terminal. Started right up, but the alternator was making an even worse noise than it usually does.

We then went down to O'Reillys to get the alternator tested, and when they came out to test it, the battery is so dead not even an interior light will come on again. It was only reading 7 volts, so I tried a jump again. This time sparks flew everywhere (attaching the neg end to the frame), like when you touch the pos & neg ends together. So I try putting it on the neg terminal of his battery again, and it seems fine. But 10 seconds later, smoke starts POURING out of the alternator. We give up, and he shells out $50 for a new battery to get the car home (alternator unplugged of course). He's going to try to drive it tommorrow on the battery only, which might be ok since the car was swapped to carb and has no electronics to power.

So here's the question - I know the alternator is probably shot, but I don't want to put another one in until I know what caused this super fast draining and the deal with the frame. Is something grounding out? Battery cables? Can the bad alternator itself cause all this? I couldn't find much in a search.

Vader

Better start looking at connections. That problem with the grounded end of the negative battery cable should be a good starting point.

steele

So just start cleaning ground/connections? I can't think of much else. But the car starts and runs better than it ever has with the new battery and alternator unplugged. The battery hasn't drained any either.
Also, why is the FRAME of the car ungrounded? Could I confirm this by touching the neg end of my multimeter to the frame and the positive end to the battery?

steele

ttt

Vader

Obviously, you have an alternator problem if you let out that much of the smoke. Regardless, the chassis of the vehicle MUST be grounded. What I indicated (but apparently not clearly enough) is that the connection of the negative cable to the chassis is a possible problem, given your description of the sparks and heat generated there when you attempted to jump-start the vehicle.

By your current description, you can meter a voltage differential between the negative battery terminal and chassis. If that's the case, the negative connection is definitely a problem.

steele

I understood you, I was just asking about checking the voltage on the frame. Thanks!