Odd electrical problem


Amphi Guru & Former IAOC President
For the 1st time in 8 years I have an electrical issue in my white Amphi. When restoring the car I paid particular attention to the harness and proper grounds. It has paid off so far.

It is (-) neg ground, alternator car w/Pertronix ign system and coil.

I am getting high voltage back thru the (-) neg terminal and thru the original wiring. When a test light is attached to the (-) terminal on the coil it blinks rapidly while trying to kill the engine. If I rev it a bit it won't die. I have replaced the coil and pertronix unit, but still I get this high voltage backfeed? I have not measured the actual voltage other than with my calibrated fingers. It's NOT 12V as expected, that's for sure!

What could be causing this??? Possesed by the drunken spirit of Joseph Lucas himself?


Active Member

I've got the same setup in my 2 cars but have never looked into some possible high voltage on the primary side of the coil. What was going wrong with the car that made you start checking around? Those Pertronix modules are hard to kill (and easy to suspect), but I don't know if the coils have the same reliability. I've been using one coil for 6 years and another for 2 years with no problem. I've never checked for some high voltage spike at the primary but perhaps it is normal. What made you start checking around.

John Friese

67 White
67 Red


Amphi Guru & Former IAOC President
John,What made you start checking around.

I use the ign "on" wire to trip the relay that operates my vacuum pump for my hand controls. I noticed a clicking sound and it was the relay being beaten by the flickering voltage spikes.

Could the regulator in the Alternator do that? There does not seem to be any problem with it. No voltage spikes at the 2 connections on the Alternator. Humm??