'91 Custom v6 3.8l Battery Drain?

Hey all, I bought a '91 Regal custom v6 3.8l with 142k mileage about 3 months ago, but only started driving it in the last 3 or 4 weeks (the car needed brake work and other things....not to mention I didn't have my license yet lol). After fixing everything required to get it on the road (besides things like replacing the radio antenna and such), I got my license and started to drive.

For the first week or so, the car drove absolutely fine, with no obvious problems. Now though, the car battery has started to drain overnight (if I didn't drive it within about a 12-hour period then the battery would die completely and I'd need to jump it). I'm not leaving anything on, and the battery is brand new (costed roughly $70-not top of the line, but not bottom of the barrel either).

There are no shorts in the fuses either, as I tested them earlier today with a voltmeter after some advice from a friend. This morning I drove to church, and on the way back out I tried to start the car, and after a 2.5 hour service the battery was dead. (normally as I said it takes about 12 hours).

I've resorted to just pulling the positive battery cable off the battery every time I get out of the car to simply keep it from draining.

Any ideas what could be wrong? I live in the city so I do do a lot of short distance driving and frequent starting, but I do drive to the outer towns often, with the same problems.

(oh, and sorry for such a long post, but I'm trying to help you guys as much as I can to help me lol)

(and another thing: I'm just learning all of this car stuff, so I don't know much yet)

drive it to a car parts place like Auto-zone or someone who will take the alternator and test it. if your alternator(the vehicles battery charging system) has failed, your vehicle will run on whats left in the battery, or may only be charging your battery a small amount.

could be other things like stuck lamps illuminated, check under hood, trunk etc and see what you find. good luck

Thanks for the reply.

Do alternators sound a certain way when the battery is charging as opposed to when it's not? The guy that suggested I check the fuses said that he could "hear the battery charging" when we last had to jump it.

I've looked and looked, but I can't seem to find anything left on when I shut the car down.

Pulling the battery cable does seem to help, and I haven't had to jump the battery since last sunday. If the car were running on one charge (and then small charges everytime I drive), then the car should still eventually run out of juice, and I'll have to jump it again? The battery display on the dash is still up there, at maybe 16 or so (it drops to about 12 before I turn it on, and then jumps up to 16 while I drive).

I'll be sure to head to Autozone though. Any idea on whether they charge to do something like that?

(oh I think it's irrelevant by now, but it's a Regal Limited, not Custom. I had forgotten lol).

as far as autozone is concerned, its usually free, they hook something to the car and look at the charge. if the gauge is displaying 16(normal) it makes me wonder if you really do have a short somewhere, keep in mind that you need to check everything under the hood. the alternator should not whine or whistle, although if you hear a whistle, be sure to find out what it is. it may be a belt or something. and lastly i know your battery is new, but if possible, switch with one thats good and see if it will drain down. you are at a process of elimination standpoint, its really your only choice left. let me know.

with no obvious problems. Now though, the car battery has started to drain overnight (if I didn't drive it within about a 12-hour period then the battery would die completely and I'd need to jump it). I'm not leaving anything on, and the battery is brand new (costed roughly $70-not top of the line, but not bottom of the barrel either).

Mine did that same thing for awile and a couple of batteries and an alternator later, I found out the crappy stereo had a tape jammed in it and was draining juice without the darn thing even turned on. Some kind of automatic contraption that was just barely on, but not draining it fast enough to pop a fuse.

To track down a battery drain problem, you first need to see the drain. Your tool could be either a volt meter or alternately you can construct a light bulb with two leads so that it will glow when there's electricity flowing.

Procedure:
1. Disconnect the negative battery cable from the battery.
2. Wire the two leads of either the voltmeter or light bulb tool between the disconnected battery cable and the negative battery post. You should see the battery drain at this time on the voltmeter (or see the light bulb tool lit).
3. Pull the fuses in the car one at a time, and observe if the battery drain stops. When the drain stops, you've found the problem circuit and need to investigate why.
4. If you've pulled all the fuses and saw no change, the problem circuit may be one with no fuse in it like the alternator or starter circuit. You would need to disconnect them manually to test.

To track down a battery drain problem, you first need to see the drain. Your tool could be either a volt meter or alternately you can construct a light bulb with two leads so that it will glow when there's electricity flowing.

Procedure:
1. Disconnect the negative battery cable from the battery.
2. Wire the two leads of either the voltmeter or light bulb tool between the disconnected battery cable and the negative battery post. You should see the battery drain at this time on the voltmeter (or see the light bulb tool lit).
3. Pull the fuses in the car one at a time, and observe if the battery drain stops. When the drain stops, you've found the problem circuit and need to investigate why.
4. If you've pulled all the fuses and saw no change, the problem circuit may be one with no fuse in it like the alternator or starter circuit. You would need to disconnect them manually to test.

Excellent advice! Jumping a 91 isn't a really a grand idea because the ECM doesn't really like it much. The thing is very touchy. Do you think it's a good idea to reset the ECM after a battery change to help it "learn" how to idle again? :confused:

The PCM or ECM will relearn engine parameters once you drive the car for awhile. Drive it like you normally would and do a few wide open throttle pulls also. Unless you put a spike on the ECM, it should not hurt it to jump the battery. Be careful not to connect jumpers with car running or disconnect while the other car is charging and you should be OK.

check some often missed locations such as, a stuck trunk lamp. or hood lamp. glove box maybe. also take a look at the power antenna if equipped. a stuck relay may cause a drain. good luck.

do you have a amp or such in the trunk those not wired correctly can cause problems

Here'sone for ya. I sure hope someone can help me as I need to fix this and can't afford to take it to a shop. I have done the below.
Procedure:
1. Disconnect the negative battery cable from the battery.
2. Wire the two leads of either the voltmeter or light bulb tool between the disconnected battery cable and the negative battery post. You should see the battery drain at this time on the voltmeter (or see the light bulb tool lit).
3. Pull the fuses in the car one at a time, and observe if the battery drain stops. When the drain stops, you've found the problem circuit and need to investigate why.
4. If you've pulled all the fuses and saw no change, the problem circuit may be one with no fuse in it like the alternator or starter circuit. You would need to disconnect them manually to test.

I have pulled all fuses *and* manually disconnected the alternator and starter. I still have 12 volts between the negative post and the disconnected battery cable. Please help!

I had the same problem in my wife's 93 regal. Her dash lights are supposed to go off about 30 secs after she shuts her car door. They were staying on all night (and day) after she shut the door. So I started pulling the courtesy (Sp) light fuse and it stop killing my battery. replaced the headlight switch (dash switch) fixed my problem.
hope this helps.
Matt