Del has laid out realy good info above. Print that. redaw the diagram yourself so you will remember what each wire connects to.
Slow down, take a little time to get a hang of what each part does.
Its actually a very simple system, and pretty easy to seperate which component failed.
Distributor. The connecting wires go to a magnetic pickup. Take the cap off and look. Every time the point on the reluctor goes by the pickup, a small electrical pulse is sent down the connecting wires. Yes, the pickups occasionally go bad. Very occassionally.
ECU. Amplifies the magnetic pulse to open and close the ground connection of the power flowing through the coil. The ECU itself needs power to run, but not a lot.
View attachment 1715303617
Ballast Resistor Reduces the power going to the Coil when the engine is running, and in most cases also the ECU.
Coil's Primary Resistance and the Ballast Resistance together regulate the current through the coil. That's why these need to be matched.
During start, voltage is only 12.5 Volts at best. That's one reason why the ballast resister is bypassed during start.
Illustration from 1973 Electronic Ignition Repair p. 3
