1G 91-94 Starts but missfires

[Dalton Smith]

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So Lately my Daily Driver has been running fine, pulls hard at over 50lbs/min, Done me right for over a year. So when I turned it on and it didn't want to start without throttle or idle due to what felt like a bad igniter Which I'd experienced prior on my other DSM I was sure of a quick fix. So out comes the tools and all my spare parts.

Immediately Plugged in the cable and started testing. I had no contact between Cylinders 1 & 4 on the Misc. Tab within ECMLink. Cool, It's likely the Igniter as I thought, which it wasn't ( I have a few kicking about )

Checked out good:
-Plugs
-Wires
-Coils
-Igniter
-wiring from ECU to Igniter to Coils via Ohm Signal (Connectivity)
-Has Spark
-Injectors tested ad cleaned 1187cc/1200cc
-Fuel pressure tested solid at 45psi and is located after the rail
-Swapped ECUs and same issue.
-Swapped MPI Relay (Had temperamental starting prior #Fixed that)

So I revert it all back to how it was prior, it starts. Idles. Drives. SO I grab the my laptop and hit the road.
I then had immediate injector loss Mid Pull. Found a Clue to my issue. I had a solid 62% curve which spiked down to 0% before coming back. Not enough to flinch the AEM AFR gauge though, It lasted maybe .100 of a second. Car then reverted back to it's 2 cylinder status after decel. With it at this stage and limped back into my driveway, I again tested the injectors and it was reacting to me turning off all of them 1 by 1. Leaving me with a multiple symptom headache.

I've been at this for a few days now, and with my years of experience pointing to an internally corroded wiring harness, I wanted to get some 2 cents on this Diagnosis before I find another and rebuilt it due to sites like Rywire discontinuing theirs.

I have not done a Resistance check yet, however, I don't know what else it could possibly be.

 

[Jacob hoke]

Have you tried replacing the coil pack itself iv had this happen in the past and had a spare that I switched out and cleared right up after all if it original equipment its 25+ years old now

 

[Dalton Smith]

I've neglected to repost on here, I dug about my stache, swapped CAS, and kept running datalogs to try and pinpoint what was going on. Basically I had corroded wiring for the Cylinders 1&4 signal to the igniter. I replaced about a foot in length total. Harness is just brittle and I presume moisture got past the cracked insulation. The wires themselves had started to change color so I snipped those bits out and had less resistance. Band-aide it while I redo my other harness and get it in the car.