4 pin ECU doesn't work. Old 5 pin does.

TrailBeast said
It matters which ballast resistor you have.
Generally the 5 pin ecu takes the 4 terminal ballast, and the 4 pin ecu uses the 2 terminal ballast.
This is why the 4 pin works on both.

Do a google image search and check it out.

Thank's man. I'm familiar with the wiring.
Like I said, For discussion sake, let's assume we have a good 4 pin ECU, coil, distributor. With old factory electronic ignition wiring.
Factory would assume a 4 pin ballast.