1996 Chevy Corsica Alternator good or bad?

DSUTTON850501

MEMBER
1996 CHEVROLET CORSICA
6 CYL
FWD
AUTOMATIC
67,000 MILES

My sisters car recently died on her while she was driving. First thing I thought was alternator went, So I pulled the alt and drove up to a parts store and they tested it. Sure enough it was bad. So I installed a new alternator but now I am having the problem of after jumping the car it will run but only when the car is at high idle like keeping my foot on the gas pedal and as soon as I left off it stalls out and I have to jump it all over again. Do you feel that I may have bought a bad alternator? Or is there another problem else where that I should be looking at or maybe overlooked?

7 Replies

RASMATAZ

MECHANIC
75,992 POSTS

And I have to jump it all over again. Why did you have to do this? Does it refuses to crank over? Comeback and tell me more about it and at the same time get a volt meter ready and I will teach you how the charging system works-your shot.

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Tuesday, January 15th, 2008 AT 9:22 PM

DSUTTON850501

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Yes it refuses to crank like when the battery is to low. Voltmeter tested the battery got around 10.5 volts when it shut off I know thats a little low. But im just wondering why does it stay running at high idle but at low idle and it stalls out why do I have to jump it all over again?

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Tuesday, January 15th, 2008 AT 9:40 PM

RASMATAZ

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But im just wondering why does it stay running at high idle but at low idle and it stalls out why do I have to jump it all over again?

At 10.5 volts, that's enough to power the ignition and it goes below 9 volts, it's gone for good.

Either ur alternator is not putting out or ur battery is not taking it.I strongly recommend that you get the alternator/battery checked out. Something's wrong between the two. Have these two checked out and then comeback.

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Tuesday, January 15th, 2008 AT 9:53 PM

DSUTTON850501

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Ok I pulled the alternator and had it tested it passed all fields. Then pulled the battery charged it and had it tested for a possible bad cell. And again battery was good. I put the car back together again. Started it and tested the voltage I got about 12.03-12.05 while car was running with about.0-.25 volts comming out of the alternator ran and drove it around for about 15-25 min then checked it again battery ended up with about 10.4 volts running. I checked grounds and wires best I could all looked sealed and intact so now im stuck. Have any ideas whats the problem? Or can you help with another idea or something to check?

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Thursday, January 17th, 2008 AT 6:12 PM

RASMATAZ

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I put the car back together again. Started it and tested the voltage I got about 12.03-12.05 while car was running.

This readings is not gonna make it-it should read 13.5volts or better even if you have the lights and heater On. If you're positively sure the alternator and battery is good-you might want to check the computer whether the regulator is field generated in it.

At 10.5Volts that's not even enough to tickle the starter or power up the igniton system.