When my 77 idles the voltmeter reads 13V~14V . If I am running about 2500RPM and only the radio on it jumps to 16V . If I turn on the fan or lights then it goes back to 13V~14V. I checked the grounds and cleaned the contacts in the VR . Is that normal or is the VR shot? Thanks, Jim

Jim

My '77 had the same symptoms as yours until I upgraded to the ZX alternator and removed the VR, removed the fusible links and replaced them with a maxifuse upgrade from a Caddy Catera. Also, the headlight relay upgrade didn't hurt either.

I didn't mean to avoid answering your question directly, but with the changes I made, I don't think there was a 'smoking gun' to point to. My wiring was in rough shape which wasn't helping the battery charge or regulator function correctly, and of course we all know about those fusible links.

Check your voltage at the battery under all of the conditions you state and compare the number vs. the gauge reading. I'm betting it's not as much of a swing as the gauge says it is.

Wayne

Thanks, I'll check the battery voltage at 2500 RPM tomorrow . Jim

At 2500 rpm my voltmeter will still read full voltage even with a full load on it (lights, radio, windshield wipers, rear defogger).

Alternator is a rebuilt one I got from Checker 3 years ago, VR is a "Niehoff" brand one I also got from Checker about a year later, so my charging system is pretty 'new,' all things considered...

Also, I think the OEM VR can be adjusted IIRC.

I don't think the behavior you've got is 'abnormal' by any means, but it's probably not as good as it could be...

The one thing I overlooked was to clean the connector to the VR and there was alot of corrosion in there. I also cleaned the contacts in the VR and now it seems much better. Thanks, Jim