denso alternator overcharging

I did the denso alternator conversion. Also have done the ammeter bypass. All new wiring. Only problem is that once and a while, my voltmeter will show momentary spikes, like the alternator is overcharging for a moment, then not overcharging. Sounds like a ground issue somewhere. Ordinarily, I would think it was a voltage regulator ground problem, but the denso has an internal regulator. 69 Road Runner. Any ideas?

regulators change due to ground or sensing voltage.
not sure how the internal regulated work, but that is the only other thing to check, other than a bad alt.

How many volts does it spike to?

I had my 120 denso overcharging time to time ended up being the contact on the keyed power plug at the regulator. put a new end on the keyed power and that fixed it. so contact through the bulkhead could also give it a low voltage signal and want it to charge more!

Quote:

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How many volts does it spike to?

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Looks like about 16 on the gauge. It is very momentary -- the gauge needle will flick back and forth.

My bulkheard connectors and wires should be good as they all are new.

I ordinarily would think this was a voltage regulator ground issue. Does anyone think I should run an extra ground wire from the alternator case to ground? Any issues with doing that?