‘72 and ‘73 Imperial intermittent no spark.

[kevinm1955]

Okay, this one has me pretty well stumped. I’ve owned my ‘72 Imp for 26 years and it is a late build, so it has electronic ignition. Once in awhile, I get a no start condition. Crank, crank, crank and nothing, then it fires as the key is let off “crank”, to “run”. It’s pretty intermittent, so it’s hard to track down. Over the years, I’ve replaced the ECU, ballast resistor, cap and rotor, wires, plugs, ignition wires and ignition switch. It’ll be okay for awhile and then the problem will recur.
Now, I’m working on a friend’s ‘73 Imp and it has the same problem but it occurs more often on this one. I’ve now replaced the ECU and added an auxiliary ground, replaced the ballast resistor, distributor, spark plugs, battery and coil and it still will have the problem recur. It’ll be fine for a week, then the problem crops up.
I don’t usually just throw parts at a car- I try to diagnose the problem, using logic. This car has a strong +12v to the positive side of the coil but gets no spark out of the coil, until you’re shutting the key off- intermittently of course. Sometimes, it’s just fine. Has anybody ever figured this out? @DocMcNeedy does this happen to any of your Imperials? Help!

Check the bulkhead connector, pull it off and reinsert it. Should that not solve the issue, check the wiring in the ignition circuit. Lose, partially torn or broken, especially at the bulkhead connection

 

[Clover]

Check the bulkhead connector, pull it off and reinsert it. Should that not solve the issue, check the wiring in the ignition circuit. Lose, partially torn or broken, especially at the bulkhead connection

Thanks for your input. It looks like it was the bulkhead connector alright. Today was day four of it firing up with no problem, after cleaning pin 12.

 

[Ross Wooldridge]

Yay!!

What about the other car?

 

[Clover]

Yay!!

What about the other car?

I’m definitely going to check it soon!

 

[Old man Utah]

I've had this problem with every fusie wagon I've had over the past 30 years. All have been daily drivers so I've encountered it many times. Car runs fine and I get out go back 5 minutes or a day later....won't start! Pull the wires on the ballast resistor one by one, put them back on and the car starts right up again and is fine usually for a long time. Have the same problem occasionally on my 1975 Town and Country.

 

[cuda hunter]

Thanks @Clover for going through this with detail on the forum.
I have a 77 Ramcharger 440 that always starts on the back off position.
I've changed everything and thought I had gone through everything as well.
I do not recall taking the bulkhead connector apart and will try that with the truck.
It's been doing it for some 15 years now. Probably because I used to mud and water it like mad while mountain driving.
Thanks a bunch, can't wait to hear if this is the same issue with the 73 Imperial.