Alternator Overcharging
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 45
Likes: 0
Alternator Overcharging
Sorry to do this again but I am at a loss. This is a follow-up to my previous post under General. This problem is on my 80. After all the tests on the alternator and battery (new) my original gauge still reads 15ish. Was told it was the gauge and just to drive it. Me not wanting to give up and have a guage that is working I finally purchased a new one. Now it pegs at 18. Took it out and put original back which still reads 15ish. Any final suggestions on what I can do.
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
I would suggest that you have a regulator issue. Sounds similar to the problem I had on my 73. Your alt has an internal regulator which means you will probably have to get a new alt. You can find out for sure by putting in a known good alt and see what the guage reads. Or, you can take the chance like I did and buy a new one. Fixed my problem with the pegged guage.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
An 80 has a voltmeter, it measures voltage and it is not calibrated to 3 decimal places nor is it traceable to NSTA standards. All you need to do is check the alternator output with a known good calibrated voltmeter, anything made by Fluke will do nicely. The alternator should put out around 14v with the lights on and engine speed up above 1000 rpm. Compare the test meter reading with yours and see what the difference is. As long as the good meter says your ok then drive it.
I have not done surgery on a vette voltmeter, it might even be tuneable, I don't know. I'll take a look at mine tonight
I have not done surgery on a vette voltmeter, it might even be tuneable, I don't know. I'll take a look at mine tonight
Intermediate
Joined: Apr 2007
Posts: 29
Likes: 0
From: Port Orange Florida
Voltage
Hi - First post from a new poster here...
I brought mine into the shop afetr purchase because the gauge read 18volts. The shop rebuilt the alternator, installed it and it still reads 18 volts. But it's only putting out 14.
Good luck!
I brought mine into the shop afetr purchase because the gauge read 18volts. The shop rebuilt the alternator, installed it and it still reads 18 volts. But it's only putting out 14.
Good luck!
Burning Brakes
Joined: Jan 2006
Posts: 1,154
Likes: 1
From: St Augustine FL
I need to replace my oil pressure gauge and figure out why the sissy lights on the right hand side of the gauge cluster dont work. I am assuming I have the combo problem bad gauge and bad printed circuit board.Good luck
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 45
Likes: 0
thanks for all the advice. Sounds like I may try a new alternator and than go to new board. We will see after that. I had already replaced the regulator and triodes but not a real big difference. After all of this my guess is the alternator. Will keep you all posted. Have a great weekend and mothers day!!!!
04, 2004, 78, alternater, alternator, c3, charging, chevy, corvette, forum, gm, overcharge, overcharging, sc, vette
