Bouncing Volt Meter
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Joined: Feb 2002
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From: Lakeville MN
Bouncing Ammeter
While driving down the road at a constant speed, my amp meter constantly bounces from about 2 to 15 amps at about 1 second intervals. It doesn't bounce when there is some current draw from something like the brake lights, head lights, etc. I replaced the voltage regulator internal to the alternator a while back but it didn't seem to help. Any ideas?
Last edited by dogr74; Jul 19, 2004 at 06:40 PM. Reason: Was thinking amps but typing volts
Instructor
Joined: Dec 2002
Posts: 242
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From: Port Orchard Washington
If your actual voltage reached 2V, you would know it because that will not support the coil. Also depending where you connected the voltmeter, it should not show below 12V because of your battery. It sounds like your voltmeter is defective. At constant speed with no accessories on the alternator makes max. voltage. Your voltmeter gets this high voltage and is being overdriven. When you turn on an accessory (lights, etc.) alternator voltage decreases slightly, no longer overdriving the instrument. Swap it out or change the connection location if it is an aftermarket unit.
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Joined: Feb 2002
Posts: 77
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From: Lakeville MN
Bouncing Ammeter
Well, its not the coil or condensor (I put on new ones and the problem didn't go away... got a new Pertronix coil out of the deal though!). The bouncing is too regular for a loose wire and also ocurs when parked running at RPM's >3000. Sounds like checking out the alternator is the next option unless anyone has any other ideas.
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Joined: Feb 2002
Posts: 77
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From: Lakeville MN
Case Closed
The problem was the alternator. I had it tested and it showed a dead short even though I haven't had a weak battery. Had it rebuilt by a local auto electric shop and all is well. 
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Joined: Feb 1999
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From: Lenoir City Tennessee
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Glad to hear you got it fixed. Now if I can just remember this if it happens to mine. Thanks for posting your findings. 
