Major problem, please help!
Thread Starter
1st Gear
Joined: May 2009
Posts: 1
Likes: 0
Major problem, please help!
Hello, I have a 1993 C4 Corvette.. I just recently discovered a problem. My battery was dead one day so I jumped it, it started up and ran fine. The next day it was dead again so I thought ok, I have a parasitic leak and I checked everything but everything was fine. I jumped the car again and took it for a quick spin.. then parked and turned the car off, I tried starting it again instantly and the battery was dead again. My father told me that my battery or alternator could be dead, but he isnt a mechanic. So before i spend money to replace my alternator and battery I was wondering if anyone on here could please help me out ASAP and maybe give me a diagnosis and some advice. Thanks!
Le Mans Master
Joined: Sep 2002
Posts: 8,991
Likes: 2
From: Hanger 18 Taxachusetts
sounds like the battery.
If you can jump start it and it runs fine then it is running off the alternator. Since you said if you shut it off and try to restart right away and it is dead that sounds like a battery as well, it wasn't off long enough for any kind of drag to be killing it.
If you have a volt meter I bet if you measure the battery it will be less than 12v with the car off and about 14v with it running.
JMO as I did not stay at a Holiday Inn Express recently !
If you can jump start it and it runs fine then it is running off the alternator. Since you said if you shut it off and try to restart right away and it is dead that sounds like a battery as well, it wasn't off long enough for any kind of drag to be killing it.
If you have a volt meter I bet if you measure the battery it will be less than 12v with the car off and about 14v with it running.
JMO as I did not stay at a Holiday Inn Express recently !
Burning Brakes
Joined: Apr 2009
Posts: 877
Likes: 0
From: Broken Arrow Oklahoma
sounds like the battery.
If you can jump start it and it runs fine then it is running off the alternator. Since you said if you shut it off and try to restart right away and it is dead that sounds like a battery as well, it wasn't off long enough for any kind of drag to be killing it.
If you have a volt meter I bet if you measure the battery it will be less than 12v with the car off and about 14v with it running.
JMO as I did not stay at a Holiday Inn Express recently !
If you can jump start it and it runs fine then it is running off the alternator. Since you said if you shut it off and try to restart right away and it is dead that sounds like a battery as well, it wasn't off long enough for any kind of drag to be killing it.
If you have a volt meter I bet if you measure the battery it will be less than 12v with the car off and about 14v with it running.
JMO as I did not stay at a Holiday Inn Express recently !
Instructor
Joined: May 2009
Posts: 208
Likes: 3
From: Hobe Sound, Fl
I recently had this problem, take your alternator and have it tested, if its bad, buy a new one. If its fine it might be your battery, have that tested. Its most likely the alternator since it is not starting after you ran it.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
It takes a long time to fully recharge a battery. You cannot jump a dead battery and drive your car for 15 minutes or so and expect to gain much of a charge. It is no wonder to me that it became dead again in a short time. Whenever you have a dead battery, charge it at least overnight with a battery charger. Also, dead batteries draw a large amount of current at first and this large current heats alternators and shortens their life. Alternators are not made to charge up dead batteries! You may have excess leakage current which discharges your battery. GM says leakage current should not exceed 50 milliamps. My 87 draws 27 ma. and I have no battery problems. You can measure the leakage current with an ammeter in series with the neg battery cable and the neg battery post after the courtesy lights time out.
First things to check are, in the dark look for vanity mirror lights, door map lights, center console lights, underhood lights. Do not leave your key in the ignition because this keeps the anti theft circuit on and will discharge your battery. Do you have a CB, GPS, radar detector, aftermarket alarm, radio or audio amplifier? Check em.
With the ammeter connected, you can pull fuses one at a time while you watch the ammeter and find the circuit that is drawing excess leakage current.
First things to check are, in the dark look for vanity mirror lights, door map lights, center console lights, underhood lights. Do not leave your key in the ignition because this keeps the anti theft circuit on and will discharge your battery. Do you have a CB, GPS, radar detector, aftermarket alarm, radio or audio amplifier? Check em.
With the ammeter connected, you can pull fuses one at a time while you watch the ammeter and find the circuit that is drawing excess leakage current.
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Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
The things some people will think up...
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
However that was when there were no electronics, circuit boards, or computers in vehicles NO way should anyone try this on a car with a computer in it. The battery maintains constant voltage for the electronics the alternator is just for maintaining the charge back to the battery. Trying to run with out a battery could fry every piece of circuitry in the car I hope the OP didn’t try this. All newer cars will throw a code if battery voltage drops below safe levels.
Burning Brakes
Joined: Apr 2009
Posts: 877
Likes: 0
From: Broken Arrow Oklahoma
Pulling the cable was a good test for the late 60's early 70's cars. Most of the alternators didn't put out enough power for all of the crap we added later(CB,8track etc.) So if your car was having this issue . if you pulled the cable and it died it was almost always the Alternator.
Even though I have the electronic equipment to check this stuff. I would still pull the cable from my 69 GTX Conv. if I suspected alternator problems.
This is not the way to test an alternator for a 4 wheel rolling computer.
Even though I have the electronic equipment to check this stuff. I would still pull the cable from my 69 GTX Conv. if I suspected alternator problems.
This is not the way to test an alternator for a 4 wheel rolling computer.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Pulling the cable was a good test for the late 60's early 70's cars. Most of the alternators didn't put out enough power for all of the crap we added later(CB,8track etc.) So if your car was having this issue . if you pulled the cable and it died it was almost always the Alternator.
Even though I have the electronic equipment to check this stuff. I would still pull the cable from my 69 GTX Conv. if I suspected alternator problems.
This is not the way to test an alternator for a 4 wheel rolling computer.
Even though I have the electronic equipment to check this stuff. I would still pull the cable from my 69 GTX Conv. if I suspected alternator problems.
This is not the way to test an alternator for a 4 wheel rolling computer.
I wouldn't mind seeing a pic of your '69 GTX if ya' got one lying around on your hard drive..... cooooooool car !!!!
