So I bought this 86 Fiero with the Iron Duke/5 speed combo. This ignition has absolutely giving me fits. The car has sat a while and had a noticeable ignition miss so I changed the cap rotor, wires, plugs, pickup coil, ICM and coil. I used Ac/Delco on the ICM, pickup coil and coil. It ran fantastic for about 50 miles then stopped getting spark. I found I had pinched the pickup coil wire under the cap but it didn't look like it broke the insulation. A friend suggested I use a better quality cap and rotor with brass terminals so I replaced those, and it fired right up. Ran great for about 50 miles, then quit again. So I thought I'd try a brand new complete distributor from Amazon. Started right up and ran great. For about 50 miles then quit again. The tach is jumping when I crank, the fuel injector is putting fuel down the throttle body, but no spark.
Iffy tach filter, ignition coil, even ECM getting hot can do this.
Remove the console and drive to see if problem stops/changes. If cooler ECM helps then is "dead" and save the PROM to move to new ECM. See my Cave, HE Ignition & ECM Heat
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Is the tach rising to 200 rpm during cranking and dropping back to zero after cranking? Or is it bouncing around during cranking. Bouncing around would indicate a bad ignition coil. Ignition coils can be destroyed by high resistance in the secondary or pulling plug wires on a running engine.
Has anyone on here ever swapped in one of the early Citation Iron Duke vacuum advance HEI distributors? Something I thought about to get to the traditional 4 pin HEI module.
So I found the problem; there was a hole burned right in the bottom of the coil. So now the question is, was this the problem or a symptom of the problem. Only other issue I could find was the plug for the hot/ground leads to the coil was really loose and wouldn't snap in place. I had another connector so I changed it. Maybe this caused it to overheat?
The secondary voltage will rise until it finds a path to ground. Normally that is via the dist, spark plug wire, spark plug and it's gap. If there is a reason the voltage can't find a ground the normal way, the voltage will rise until it finds a ground some other way. It looks like it found it's ground via a weak spot in the coil case.
Yeah, it was brand new. I just put it on about 150 miles ago. The old one was good, I just did a full tune up when I got the car.
So far so good. I've been making some short trips and everything is still working.
One other issue I noticed; this seems to dump a lot of fuel in the throttle body on initial startup and chokes the engine. After a few seconds it smooths out and the spray looks normal. Anyone ever had that issue?
