[Geobart]

My 1964 GTO stopped charging the battery. I replaced the alternator and regulator (external) and now it does not turn off with the key. I also repaired a wire from the firewall to the horn relay because the insulation was cracked. Any help woul be appreciated.
Geo

[george kujanski]

What else did you change? Standard or HEI distributor? Is the regulator a standard type or newer electronic type? Any change in the regulator wiring? A newer 10 SI style alternator or original OEM type?

George

[Geobart]

I replaced the alternator with original style. The regulator is external again original style. The distributor is running pertronix ignition.

[Geobart]

Replaced alternator with oem style as well as external regulator. The distributor is running pertronix ignition

[george kujanski]

If you have a relay providing power to your Pertronix ignition, the alternator may be backfeeding enuf voltage thru the idiot lite circuit to keep the relay on. The typical fix for that is to install a diode in the regulator brown wire circuit to prevent the feedback.

If you are not familiar with a diode, it's a electronic component that acts like a check valve, allowing current to flow in one direction and block it in the other.

George

[Geobart]

Thanks George,
I don’t have a relay powering the pertronix. Everything was working until it stopped charging as indicated on my volt meter. The idiot lite was never working does not light up with key. When it stopped charging I jumped the regulator and the the alternator was charging. So I replaced the regulator and then it was over charging reading 15.3 volts and smoke was coming out from the new regulator and would not shut off with the key. Then I decided to replace both the alternator and another new regulator. Still won’t shut off with the key. I am familiar with what diode is but just don’t understand why I need it now and where it needs to go. The only other thing I did was to replace a price of wire going to the 12v supply at the junction block of the horn relay. There were breaks in the insulation and looked like it was repaired before me since there appeared to have a crimped connector. I haven’t chased that wire yet but it came through the firewall all by itself. I can’t believe that has anything to do with this but I’m no electrical whiz..

["QUICK-SILVER"]

To help narrow down what's going on...

Try cranking and cutting it off with the voltage regulator unplugged.

Clay

[Geobart]

With the voltage regulator unplugged it runs and shuts off

[Geoff]

You need the diode. MSD used to have a diagram on their website, showing how/where to connect it.