Fluctuating neg. to ground on ignition coil

Stephan D said
The ignition coil is getting between 7 and 7.7 volts at + when running at idle, it's marked with 12 Volt, I have yet to remove the ignition coil to see more text on it.

All of this stuff is called '12 Volts'. Its '12 V' system as opposed to a '6 Volt' system. But it actually runs at something above that.

The voltage the coil is getting while running is going to fluctuate with current through the resistor.

Stephan D said
Resistance between + and - in the ignition coil is 1,5 Ohms.

That's ballpark correct. What's the book say it should be?

Stephan D said
My readings at the ballast resistor:

I assume the resistance measurements were done with the key off.
The voltage drop measured indicates current was flowing through the 1.3 Ohm resistor.

Stephan D said
Battery is getting 14 volt at idle.

Probably good.

Stephan D said
ECU is branded "Standard":

So its been replaced.
Most replacement ECUs do not need the current limited by a resistor. They get power from the run wire and no longer use the 5th terminal in the connector.