It's wiggin' out again.

Hooked up an O2 sensor and gauge. Getting some really erratic readings. Off the scale lean at idle. Off the scale rich under power. Motor is running way too good to be that far out out of whack. Tech says to check the supply voltage.

Sure enough, at the alternator, I'm getting ~15V. At the Battery I'm showing ~13.5-14. That's with what should be a fully charged battery.

Flipped the DMM over to AC volts and I'm seeing 25-30 VAC. Bad diode(s)?

Everything else seems to be working fine though. No problems with charging, other than the normal dim lights at idle. Weird.

Going to take the alternator in tomorrow to be tested. Probably swap it for piece of mine.

Yep, bad diode(s) for sure. Get it replaced/repaired before it fries anything

New alternator, same problem. New VR too.

Still getting about 15 V at the alternator and 13.5+ at the battery.

30 VAC too.

Check the voltage at the blue wire feeding the VR, probably too much of a voltage drop from the ignition circuit making the VR command more field current causing more voltage drop in the blue sense wire.
$.02
Mike

Maybe.

I went back and checked the VR ground to body. I cleaned some more paint off the VR and the body as well as improved the mechanical connection (the hole in the firewall was stripped). Haven't had a chance to recheck the voltage yet, but it ohms out with good continuity now. Tonight I'll fire it up to check the voltage.