The following done to a 1970 Plymouth roadrunner.

Installed new Autometer Voltmeter and it shows 14.5 volts at idle, 12.5 @ idle with the lights on. When you bring the RPMs up it goes to almost 16 volts on the gauge. Replaced both the alternator and the voltage regulator at the same time and I am still seeing the same result. Is this just typical for an old mopar or do I have a potential electrical problem? It seems a bit high to me. The built in gauge shows a bit of a charge (10-20AMPS) after you first start the car but once the car warms up the gauge is in the center between "D" and "C". Also, I measure about 12.5 volts @ idle right on the battery and about 14 volts if you bring the RPMs up. Is it a bad gauge or do I have something else going on?

 

Mikey, you only need to post once..lol

 

Sorry, was posting to a few different forums....got carried away with the copy/paste

 

dont think you have a problem as long as the volts do not continually stay up near 16 volts. If they do stay near 16 volts for a long time [like more than 15 min.] you definately have a problem. The 14.5 volts is good.
Where is the new voltmeter connected to.{power source} It needs to go to a "key on power source" like the hot side of the ballast resistor. If it reads more than the batt. voltage, it is possible that it is innaccurate.

 

I have the voltmeter gauge coming off of the fuse block in the glove compartment. It's hooked to a key on power source. So when you say its good as long as it doesnt stay near 16V, where should I be taking that reading? At the gauge or is it more important to read what I have at the battery?

 

Well, I think the fuse block is ok. but there should be a higher reading off of the battery posts because of less connection to cause voltage drop.
Here's what you do; run a line from the hot side of the ballast resistor to the volt gauge [discon. the wire to the fuse block for now] Make sure you have a good ground for that gauge. If the readsing is still high when the rpm's go up. there is something wrong somewhere. Its possible it could be ther gauge [new one]. Try and compare it to another gauge {like on a handheld volt/ohm meter. Use the same ground and volt source and compare the readings. They should be extremely close}. If the handheld volt/ohm meter gauge reads high too, then the alt is overcharging for some reason.