Quote:

I think you should start by looking at how the ignition system was wired in. Is the ECU getting full battery voltage?




One way to do this follows:

The "dark blue" ignition run comes directly from the ign switch and powers the ignition system, and the regulator "ign" terminal. In '70 and later cars, it ALSO feeds the alternator field (isolated field), the electric choke if used.

With the car running to simulate "low cruise" stick one probe of your meter directly onto the battery positive post.

Stick the other probe on the IGN terminal of the regulator.

You are looking for a VERY low reading. Zero volts is perfect, anything over .2 (two tenths of a volt) is too much and indicates problems in the "dark blue" "ignition run" circuit. Most likely "usual suspects" are the bulkhead connector, the connector on the ign switch, or internally in the switch itself.

If you've added some sort of accessories?? like fans, look where they are wired. If you are robbing power off the "dark blue" you may have a problem there.