Weird electrical problem
 

I have a 91 N/A with a street port and intake. No special stereo or extra electrical gadgets. The other night I was driving and the Dash and head lights went super bright, the heater fan went into overdrive and the voltmeter shot up to 16 volts! The car will do this at idle in my garage without moving it, but only after the engine warms up.

I pulled the alt and had it tested. Fine. I changed to another battery, no help, I disconnected my stereo. Still no help. I figure it's a loose wire or ground. Any ideas what to try or trace?

I assume that the fuses are no blowing when this happens? Have you check the voltage with a meter other than the stock one?

No fuses going, and the voltage is fine. If
I use a dead battery and boost it, it still runs fine but still spikes in voltage. The headlights spike in brightness with any battery.

Also I get no check engine light warnings

Sounds like it could be your voltage regulator. You wouldnt happen to have a fd alternator?

Nope, it's an fc alt, and it's an internal regulator on the alternator, so it should have shown up on the bench test right?

You did a bench test on the alt. or is this a newone?

Regualtor has failed on the alt or the referance wire to the alt has come undone.

Do not ever drive the car if the voltage is at 16 volts. You will burn out the engine and body computers (as well as most of the lights).

You might want to listen to the eletrical guru of the RX7 Club! :icon_tup:

Yeah I benched this Alt. It passed fine. So time to do a wiretrace I guess? It isn't consistently at 16 volts, it tends to jump up and down, and sometimes be normal, other times be super high...