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Discussion Starter · #1 ·
Hey guys, I have a 95 z28 6 speed with a miss that I have narrowed down to cylinder 3. When I remove the injector plug I have no change in the way its running and no pulse, but it will start to pulse after shutting it down for a bit and then go back out. I have code 18 for injector circuit so the first thing was to ohm the injectors, found the one for cylinder 3 at over 26 ohm! Replaced with a good spare I had around. Same issue, except it's within spec as far as resistance. Checked for battery voltage at pink wire on all injectors, found all have good voltage. I was trying to use my tech 2 to clear the codes and had communication then I didn't. If I turn the ignition off and back on it will reconnect and then go back out. I'm not sure where else to go or what to check now. I'm leaning towards a driver in the ecm or possibly an ignition switch causing issues. I'm not sure what wires to check as far as to confirm one or another. What pin from the ecm should I check to verify continuity to the injector? Is there a splice? Where do the wires from the dlc go to so I can check those as well? I'm sure the fuse is good since the scanner randomly reads. Any help would be great. Thanks.
 

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Discussion Starter · #2 ·
I forgot to mention that this started after my fuel pressure regulator took a crap and I had to replace it. I also went ahead and pulled out the ecm and checked continuity from pin a21 to the injector and was all good. The voltage in the pink wire stayed constant while running, I can get a faint light on my test light on the ground side of it. Another thing is the 2 good used Injectors i put in ohm at 12.3 the rest are at 17? Both fuses are good. I need to figure out how to check for voltage dropping at the ignition switch, still working on that. At this point it's internal which I don't think because it does smooth out for a short time, the ecm, or the ignition switch. Not really sure what else is left that would knock out 1 cylinder randomly. The plug looked a little worn but still has some miles left and the wire is new.
 

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Discussion Starter · #3 ·
Think I figured it out. I decided I would start over from the beginning, pulled off #3 plug wire and put an inline spark tester in, had no spark to cylinder 3. I've had this once before where it wouldn't send spark to one cylinder. Would this be a whole opti issue or just cap and rotor?
 

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Discussion Starter · #4 ·
Ok. Anyway I'm probably going to toss a summit opti on there for now and get the ltcc setup to take the spark out of the opti. So tired of dealing with them.
 
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