Car won't restart after running for more than 10 minutes

1975 PONTIAC FIREBIRD
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JBROSEORG
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Have a 1975 Firebird. It starts when cold and runs fine. However, if I run the car for more than 10 minutes then turn the car off and try to restart it, the starter won't crank enough to restart the car. It's like the battery has gone dead. I end up restarting it by pushing (it's a manual 4 speed) or by jump-starting with another battery. I tested the alternator by removing the negative terminal from the battery while running and the car continued to run strong (actually idled slightly faster without the battery connected). Once the car cools off (after being off for couple of hours), it starts again so the battery seems strong. I'm stumped.
May 2, 2012 at 1:56 PM
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PROMECHANIC
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You need to start with the basics. You need to have the battery "load tested". You can have this done at most auto parts stores. After that you need to have your alternator tested. You can have this done at most parts stores too.
Removing the battery cable will not tell you if the alternator is good or not.
Doing these two things will probably tell you what the problem is.
May 2, 2012 at 2:29 PM
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DJCL
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Like Promechanic staded battery and alternator but also things like a bad starter and cables ignition timing and internal engine problems can also do this.
May 2, 2012 at 3:12 PM
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JBROSEORG
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Thanks for the feedback. Took it to O'Reilly and their testor indicated the alternator was overproducing voltage. They said it was likely a faulty voltage regulator and that replacing the alternator should solve the problem. So, does anyone have a step by step on replacing the alternator?
May 5, 2012 at 10:58 PM
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DJCL
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On that car the alternator is strate forward. Disable the battery and start removing belts
May 6, 2012 at 12:22 AM
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JBROSEORG
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Yep. Got it installed no problem. Thanks 2carpros.com
May 6, 2012 at 4:15 AM
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DJCL
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Good luck
May 6, 2012 at 7:17 AM
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