Flickering alternator gage.

[chucks1]

I had a few hours today, so did a little more testing.

I had previously run a ground wire from the VR to the engine block, but this time also ran a temp ground between the battery and VR. The ammeter kept up its' constant flickering even with the extra ground.

Being slightly impatient and better at the shotgun approach as opposed to logical troubleshooting, I replaced the VR with a new one and ran a single new, permanent 12awg ground from the VR to one of the bellhousing-to-block bolts. I then pulled, inspected, cleaned and re-installed the battery to frame and engine to frame ground cables (something I had already done last fall).

With my analyzer hooked up in the cockpit, I started the car to see what I had. For the first time in a long time, the ammeter needle was steady and, after some initial charging from the startup, hovering just to the right of center at a fast idle. The analyzer agreed with that. Going down the road I was getting a constant ~14.5v reading on the analyzer and the ammeter rock solid to the right of center. Running a load (headlights and heater fan) there was a brief dip, but then right back to right of center and ~14.5v.

This was a fantastic turn of events until 10 minutes into the drive, the ammeter dropped to 25- and my analyzer agreed, having dropped to ~12.5v and continuing to decrease in small increments. Things continued to head south for 1-2 minutes, when both ammeter and analyzer went back to right of center and ~14.5v respectively.

The same phenomena happened twice more while out driving. All is working well when things take a 1-2 minute dump before returning to normal.

Any thoughts come to mind with this one? I don't have a new alternator to shotgun into the car, but am thinking about pulling mine and having it tested.

Chuck