Car starts ... voltage drops on battery till 3 or so and dies ...

[MPrice]

Happy holidays gentlemen,

Non-porsche question but you guys haved helped out alot rebuildibng my 83na that i had to ask, (plus $$ from sale of 90 tbird is going to help with paint job for porsche).

Just prior to selling (to a friend) my 90 tbird I just installed a new altenator b/c the battery was not charging. Ok new altenator and battery later his the problem. I charge the battery to 12v approximately, the car will start. If i am holding a voltmeter across the battery, the voltage will drop to about 9 or so as the car is started and as the car runs the voltage continues to drop .. until it gets to 3-4 v and the car dies. Have used two different batterys and get the same results both times.

To me this sounds like a short somewhere, correct? After the car dies a few moments later the battery will show a graeter voltage..... so basically only when the car is actually running is there this large draw on the battery. Any help? ... cause the guy I sold it to is kinda po'd. Thanx

Mitch

[todwic]

Did you replace the alt. and then the battery when the batt. wouldn't charge the batt? If so, you may have burned out the reg. on the alt. Be sure and charge your batt. before trying to start the car with a new alt. and a half dead battery. (jump starting with new alt. and dead batt = bad)

[MPrice]

hmmm .. i think so ... looks like back to o'reilys with the alternator .. any way i can test to see if i did burn out the regulator?

[todwic]

Originally posted by MPrice
hmmm .. i think so ... looks like back to o'reilys with the alternator .. any way i can test to see if i did burn out the regulator?

O'Rielly's should have the facilities to test it for you. If you have an autozone nearby, I know they do. Call around, a lot of parts houses can test alt. for you.

[Sabyre]

Almost sounds like the car is running off the battery. Have you checked the wires to the alternator? If the alternator is working properly and all the wires have continuity you should be getting around 14v at the battery with all the accesories off. Most alternators have at least a 90 AMP output. Seems like the alternator is not properly installed. You dont even need a battery for the car to run.

How did this happen? THe battery just stopped charging? Would the car still run after a jump start? Or is this the same problem that prompted the altenator?

[todwic]

You say you have a new batt. now? I would go have the alt. tested. If it's not the alt. then I would re install and test the leads that go to your alt. to test for cont. with an ohm meter. I think it's a bad regulator (part of the alt.)

[todwic]

I'd also check the wires at your starter selenoid. gawd I hate fords!

[MPrice]

ok ill go check it out ... and no this is a new problem the just dying thing .... i thought about the starter too.

Aww .. no more domestics with this one gone .. just a porsche and v12 jag for me

[MPrice]

thanx for the help guys ... turns out the wire from the alternator running to a "diode suppersor" wtf? just blew itself apart. quick soder and vola ... bye bye tbird

[todwic]

Glad to help send a Ford away from a person that doesn't deserve the headache.

[Sabyre]

lol