I havea 1974 Duster 340 with Mopar electronic ignition, MSD Blaster 2 coil. I was having trouble getting it started, so after tracing the current it seemed it was a distributor issue. I put in a new distributor, verified if was set with 1 cylinder TDC and the rotor at the #1 plug, set timing and it was running smooth. Today, I went out and again cranks, but no start. It's getting plenty of gas. Current is going to through the ballast resistor, the ECU and the voltage regulator. There is current at the positive coil post, but not the negative when cranking, and there is no spark coming from the coil. I replaced the coil with two other brand new coils and had the exact same problem. Every part in the ignition system is less than a year old. I could not find any evidence of loose or broken wires. I even tried swapping out the ECU, Voltage regulator, and ballast resistor just because I had new spare ones on hand.
Any ideas?! This is driving me nuts.

Remove a spark plug and see if you get a spark at the plug , if not try a different coil to distributor cap wire.

There's no spark coming out of the coil to the distributor. I'll try another coil to ditributor connector wire.

well you tried just about everything except the pickup unit. I would try that next or at least unpug and ohm it.

I tried a new coil to distributor wire, brane new. Same result no spark out of the coil.

Are you referring to the pickup unit within the electronic ignition distributor? I had a working distributor in it (it worked in another car after I took it out), and I have a completely new distributor, cap and rotor in it now. I don't think both pickups could have been the problem, but I'll check it.

Any other ideas of what to check or try?

1 thing to check is the reluctor gap inside the distributor....
This should be 0.008 and adjusted with a brass feeler guage. We often find issues here, sometimes it works and other times nada.. The reluctor is a passive part and the many times people assume it is OK...

Just my $0.00..

There is definitely current at the positive coil post when cranking.

Tomorrow I'll check the clearance with a feeler gauge.

Thanks for all the feedback. Keep it coming. I'm really frustrated by this issue!!

I'll give it a try tonight. Thanks

No spark when grounding the negative post on the coil. I tried touching a wire from the coil postive to the battery postive while the starter was cranking and it still did not start.
I do get an ohm reading from the distributor pickup.

Could it possibly be the starter switch itself in any way?

You can also try this. Turn on the ignition switch and from under the hood, go to the starter relay and try to start the engine by touching the hot terminal (big connection) to the small wire that goes to the starter with a screwdriver. If it does start and run there is a problem with the ignition not receiving juice in the start position on the ignition switch as was mentioned earlier. Best of luck here.
John

I hooked up my remote starter, turned on the ignition, and had my daughter hold the clutch in. Then I tried starting it at the starter relay with a remote start trigger. The engine cranked but still did not fire. I guess that rules out the ignition switch.

There's power at the ECU, power at the voltage regulator, power at the ballast resistor (all terminals), power at the coil. No spark out of the coil to distributor wire. One would think it's the coil, but I tried another brand new coil and it didn't change a thing.

The next option I'm considering is hooking up a new electronic ignition harness to the ECU and running all new wires to the connection. Maybe there's a bad line. I have a spare harness.

Thanks, I'll check that out now.

Took me a while to get back to it, but I finally got the Duster started and running. It was two things - the positive coil wire had a break in it and the negative coil wire terminal was loose on the wire. I also had to replace the coil, after replacing the wires. Then the car started no problem and ran great. I also relocated the ECU to the top of the inner fender, sanding the metal bare where it mounts and adding two brass washers as spacers under each bolt hole.
Thanks for all the help!