overcharging
other times it starts and runs but still shows 18+ at higher rpm.
An alternator that is getting unregulated power to through the field will do that.
Will have to look at the other VR options as well since it is cheaper to replace than the ALT.
Did you replace with the same MP regulator? Standard and NAPA have the same thing now.
Mike's right. review his suggestions.
Also make a little diagram of your charging system since its not stock anymore.
Make sure the wire to the field terminal from the regulater hasn't been shorted to another wire.
Finally, take a hand held voltmeter and check the voltage at the regulator input side. That's the wire coming from the ignition 'run', often dark blue or dark blue with white stripe.
^ If it reads around 14 Volts at the same time your dash voltmeter is reading 18 V, or really anything more, then the problem is resistance between the alternator output and the regulator input.
