1986 amp gauge bouncing
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Junior User
Joined: Apr 2017
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1986 amp gauge bouncing
Hi All,
A friend of mine has an 86 and the amp gauge bounces just sitting there.
I checked the voltage and its around 14.5V at the battery, it fluctuates slightly between 14.4-14.6 or so but I have a hard time believing this would show up on the gauge.
Any thoughts?
A friend of mine has an 86 and the amp gauge bounces just sitting there.
I checked the voltage and its around 14.5V at the battery, it fluctuates slightly between 14.4-14.6 or so but I have a hard time believing this would show up on the gauge.
Any thoughts?
Posting Guru
Joined: Apr 2011
Posts: 1,636
Likes: 5
From: Orlando area
How much bounce?
You would want to check amperage. A clamp on amp meter would work.
14 volts says alternator is charging but maybe the regulator (or alternator) is bad and the alternator is quickly switching back and forth from charge to no-charge causing the gauge bounce. It may not be noticeable measuring voltage since the battery acts like a shock absorber and can mask fluctuations.
If you can't check amperage, I would first check the grounding of the voltage regulator (you could run a jumper from regulator case to engine ground) or just replace the regulator. If that doesn't help, you could take the alternator to part store for bench testing.
Of course it could also be a faulty gauge and/or wiring.
You would want to check amperage. A clamp on amp meter would work.
14 volts says alternator is charging but maybe the regulator (or alternator) is bad and the alternator is quickly switching back and forth from charge to no-charge causing the gauge bounce. It may not be noticeable measuring voltage since the battery acts like a shock absorber and can mask fluctuations.
If you can't check amperage, I would first check the grounding of the voltage regulator (you could run a jumper from regulator case to engine ground) or just replace the regulator. If that doesn't help, you could take the alternator to part store for bench testing.
Of course it could also be a faulty gauge and/or wiring.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
How much bounce?
You would want to check amperage. A clamp on amp meter would work.
14 volts says alternator is charging but maybe the regulator (or alternator) is bad and the alternator is quickly switching back and forth from charge to no-charge causing the gauge bounce. It may not be noticeable measuring voltage since the battery acts like a shock absorber and can mask fluctuations.
If you can't check amperage, I would first check the grounding of the voltage regulator (you could run a jumper from regulator case to engine ground) or just replace the regulator. If that doesn't help, you could take the alternator to part store for bench testing.
Of course it could also be a faulty gauge and/or wiring.
You would want to check amperage. A clamp on amp meter would work.
14 volts says alternator is charging but maybe the regulator (or alternator) is bad and the alternator is quickly switching back and forth from charge to no-charge causing the gauge bounce. It may not be noticeable measuring voltage since the battery acts like a shock absorber and can mask fluctuations.
If you can't check amperage, I would first check the grounding of the voltage regulator (you could run a jumper from regulator case to engine ground) or just replace the regulator. If that doesn't help, you could take the alternator to part store for bench testing.
Of course it could also be a faulty gauge and/or wiring.
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