Hello,
I took out my ´83 a couple of months ago. When restarting the car, it wouldn‘t idle with rough running. I decided to set the idle as high as possible to limp it Home but then, it „snapped“ back to life, after like 30 mins. I first suspected the Carb but after replacing it with an used one of unkown condition, the Problem persisted. Coils are new and replacing spark plugs didn‘t help either. Fuel pressure is present but I have to add, that the fuel pump clicks periodically on ignition with an simultaneous „twitch“ from the gauge cluster. I‘ve read, that the trailing ignitor sends signals to the Tach as well as the fuel pump, so that would check out? I have yet to adjust the timing but since the distributor screw is rusted on, I don‘t think, it could have slipped.
Thanks in advance

 

I have an 83 also. The fuel pump turns on with the ignition regardless of what the trailing ignition is doing. The tach is counting the trailing signals.

If the fuel pump "clicks on" only when you turn the key to ignition, then that's fine, it's supposed to do that. But if it's randomly clicking while running that's wrong. An intermittingly running fuel pump could cause an issue depending on the duration of the glitching, but you do have fuel in the carb bowls so if it's stumbling but not dying/surging then I think it sounds like spark.

It could be an intermittently failing leading igniter. Since the leading and trailing igniters are the same J109 style, you can unscrew them from the distributor and swap them for troubleshooting. A quick test while its stumbling would be to unplug the trailing igniters signal and if it dies you know the leading is not sparking (it will run on trailing but poorly).

 

Sounds to me like it was running on one rotor or just trailing. @Toruki's advice is sound. Also if a car sits for a while and its an older 12A, running on one rotor when not run for an extended time is not unusual due to wear and tear.

 

@Toruki Thanks for the suggestion. I tested the Ignitors with unplugging one respectively and running the engine. Unfortunately, both run the car with the leading (radiator facing) running better than trailing.
Apparently my Tach is hooked up to the leading ignitor.
So it still might be timing?
I‘ve also watched some Videos of the Gauge Cluster on Ingition and theirs don‘t do this „twitching/clicking“. My Radio seems to act up aswell.

 

I think the fuel pump only turns on when the engine is running and getting a signal from the trailing ignitor, you gotta jump the relay under the dash to get it to stay on with just turning the key to ignition. Unless it's only a later model year thing. There's a thread about it just look up "fuel pump relay".

Those j109 ignitors are cheap, personally I'd just throw some at it and see what happens, also I think you should have your tach hooked up to the trailing ignitor not the leading ignitor, it also has to be on the negative side of the coil. That's the pulse that tells the coil to fire, the positive side should be 12v from the alternator. I believe only the earlier SA cars had it hooked up to the leading side but those also use a different style of ignitor. I think you might have something hooked up wrong or maybe backwards. Possibly when you were putting in the new coils something got mixed? Pointing towards the alternator should be the trailing and pointing towards the rad should be the leading. And from the driver's perspective sitting in the car the farther coil is the trailing and the near coil is the leading. Double check the wire colors and confirm they're going to the right spots.

 

For the carbed 12A it behaves as I described. The injected 13Bs have a more complex fuel pump enabling system, probably just as you describe? I'm only familiar with the former.

 

I was mistaken, it's only a series 3 thing so 84/85. I guess your 83 should just always be on.
https://www.rx7club.com/1st-gen-arch...-trick-597949/