Wiring?
That won't work if it's truly a 5 pin ECU, but it could be either
Only way to tell is to take a meter and "ohm" from the 5th pin to all other terminals and ground, to determine if the pin is a dummy
Boil the thing down to the simplest terms. Simplified diagrams:
Check the resistor. For testing, you can even bypass it. Get a bag of clip leads from Radio Shack if you don't have.
Make DARN sure the ECU is grounded. Scrape the mounting ears and firewall, or add a ground wire and use star lock washers.
Wiggle / inspect connectors. Suspect the distributor connector. You can hook a multimeter -- on low AC volts--- to the two distributor wires and crank the engine. The distributor pickup should generate about 1V AC
If anything extra is hooked to the coil.......like a tach or a radio capacitor, unhook it. Coil, with key on, not cranking will read anywhere from below 6V to around 8V on + side. Neg. side should be very low voltage. This is getting grounded through the ECU. That is, just like points, the coil draws current with key on.
If you hook a meter or test lamp to coil NEG and crank the engine, the light should flash, meter should jump indicating coil NEG is being switched on/ off by ECU. Don't forget---coil itself could be bad
In the diagrams below, these are poorly drawn. "Existing wire" is "ignition run." The bypass circuit is not shown. the brown "IGN2" should come to the coil + side of the resistor.
Don't make this harder than it is. On a 4 wire box, to lay it out on a bench and make it work you have only 4 wires and ground:
HOT goes to Coil + and the ECU
GROUND goes to the box
The box has a wire triggering coil neg. This works the same as points
The other two wires are coming to the box from the distributor
Older 5 pin setup
That won't work if it's truly a 5 pin ECU, but it could be either
Only way to tell is to take a meter and "ohm" from the 5th pin to all other terminals and ground, to determine if the pin is a dummy
Boil the thing down to the simplest terms. Simplified diagrams:
Check the resistor. For testing, you can even bypass it. Get a bag of clip leads from Radio Shack if you don't have.
Make DARN sure the ECU is grounded. Scrape the mounting ears and firewall, or add a ground wire and use star lock washers.
Wiggle / inspect connectors. Suspect the distributor connector. You can hook a multimeter -- on low AC volts--- to the two distributor wires and crank the engine. The distributor pickup should generate about 1V AC
If anything extra is hooked to the coil.......like a tach or a radio capacitor, unhook it. Coil, with key on, not cranking will read anywhere from below 6V to around 8V on + side. Neg. side should be very low voltage. This is getting grounded through the ECU. That is, just like points, the coil draws current with key on.
If you hook a meter or test lamp to coil NEG and crank the engine, the light should flash, meter should jump indicating coil NEG is being switched on/ off by ECU. Don't forget---coil itself could be bad
In the diagrams below, these are poorly drawn. "Existing wire" is "ignition run." The bypass circuit is not shown. the brown "IGN2" should come to the coil + side of the resistor.
Don't make this harder than it is. On a 4 wire box, to lay it out on a bench and make it work you have only 4 wires and ground:
HOT goes to Coil + and the ECU
GROUND goes to the box
The box has a wire triggering coil neg. This works the same as points
The other two wires are coming to the box from the distributor
Older 5 pin setup