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Discussion Starter #1
I'm having a little problem with my chevelle. The voltage guage fluctuates between 10-14 volts. At itle it will be on 14 volts for a while and then it will drop to about ten volts. Then the revs go up about 500 rpm. Then it will jump back to 14 volts. After a while it will stay around 10 volts. This doesn't just happen on idle either. While I'm driving 55 it will fluctuate also and then just stay around 10 volts. I had the alternator checked at Napa and they said it was fine. I made sure the belt was tight. I'm not sure what else it can be. Also I checked the battery with a multimeter and it read the same thing the guage did. Is there any advice?

[This message has been edited by moose (edited 12-16-2002).]
 

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Moose,
That sounds like a problem with the voltage regulator.

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100
 

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The problem I have with this is that a fully charged battery will show 12.6vdc on the meter at the battery....regardless of alternator output?

If the voltmeter is fluctuating, then something sure sounds like a short to pull the battery voltage down.

A test would be to do a battery voltage test at rest. It should be at full charge...if less than the 12.6 at the terminals (terminal measurement only...don't cheat) it is in a state of discharge.

If it's good at the terminals then start the car to get the fluctuation. If the meter starts to read anything substantially less...like 11 or 10 volts.. (at the terminals).....there is either a short in the wiring downstream or the battery is internally shorting.

If the voltage fluxuation is being read downstream of the battery (and the battery tested okay with the procedure above) look for bad grounds or power cables where voltage drops are apparent.

If the voltage variation is only being measured at the alternator output then the regulator is suspect.

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Steve "Jack'stands" Jack
Tech forum at www.inccn.net/techforum.htm
 

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Discussion Starter #4
Thanks for your advice. I tried an alternator that I knew worked and it did the same thing. I re-tightened the belt. Still the same problem. It's good when it's cold but once the temp gets to about 150 it starts acting up again. This started happening also after I put in an electric fuel pump. I don't know if it's to blame or not though. I checked the ground and it was fine. It also is running. The only strange thing with that is It will start at 7 psi and go down to .5 psi after a while on my guage and stay there. The car still runs though. I'm not sure what it could be. Please help!!!!
 

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Discussion Starter #7
YOU GUYS ARE GODS!!!!!
It was the alternator. I had the thing tested about 5 times and 1 time for 5 minutes and they said it was fine. I ended up putting a new one in and it works like a champ. MERRY CHRISTMAS!!!
 
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