Re: UPDATE II
Here is a partial list if things I would check...
1. The Ignition coil. Look for about 0.80 Ohm to 1.35 Ohm resistance across the primary windings. (Low voltage side)
0.45 Ohms if you are using the E-core (TFI Style) coil.
2. Check the engine ground. The entire ignition system trys to ground through the distributor housing, via the black wire from the module to the distributor.
That black wire is the ONLY ground for the entire primary side of ignition.
You can splice the black wire out of the module directly to ground.
I didn't say cut the black wire, I said splice into it, and wire it directly to your master ground, or the negative side of the battery.
Those aluminum distributor housings loose ground all the time, but that's not what it sounds like here.
3. I'd check the green wire from the module that goes to the negative side of the coil.
Lots of times that wire will corrode in the two or three connectors it has to go through, and won't allow the coil to trigger.
(This is real common)
4. I'd run a test harness, like the one I posted earlier, to rule out the factory wiring harness.
Use 1/4" male and female spade connectors, preferably insulated, to make the test harness.
You build the test harness and you have the potential to bench test all of your components.
Use a GROUNDED test plug in the ignition coil, and wire you module and coil up to the 'extra' distributor, and attach the entire mess up to a battery.
Wire it up just like the drawing.
Spin the distributor, the test plug should fire. If it doesn't, you have a bad component.
It wouldn't be the first time a coil or module was bad and the local Auto-Jerks couldn't diagnose it....
P.S., using the second distributor on your stock system almost eliminated the distributor as the cause already.
5. If you have a factory tach, I'd check on that circuit. I don't think factory tachs were offered until '80 or so, but I'm not sure, and the way the factory harness is run, if the tach fries, the ignition won't work either about half the time.
CJ8/5.2Mag is the sharpie on the factory tachs on this board.
6. Make a test plug by taking a old spark plug, and wrapping a copper wire around it tightly, and grounding it to a KNOWN good ground.
Never fire an electronic ignition with out a test plug.
Hook the test plug up to the ignition coil, ground the negative side of the coil (green wire), and apply positive power to the positive side of the coil. Just strike the positive wire to the terminal on and off real fast...
the plug should fire on some of the tries when the circuit breaks (power goes off).
7. Hook every thing up as stock, except for the power wires to the module.
Supply power for the module from the battery via an assembled jumper wire.
Spin you distributor and see if the test plug fires attached to the coil.
That will test you power circuit. I don't think that is what it is from what you have already done, but leave no stone unturned.
With a test harness you can limp home even if the entire wiring harness fries.
Most of the time it's bad connections....
"I Have The Body Of A God... Buddha"