Even though this is not directly a fuel injection problem it is related to the whole ecm, injection, est system.
Long story short, I did some completely unrelated work in engine compartment of my 90 camaro 3.1 v-6. When done I had no spark and no injector opening. Security light comes on and goes off as normal. Fp primes when key turned on. No spark unless I do the old trick of attaching wire to tach terminal and touching it to ground. Coil fires then.
System uses small cap, separate coil, 8 pin icm.
When I put a test light on control wire, white wire, light comes on with key on. Does not blink when cranking engine or turning dist by hand.
1)I have tested wiring to ecm for continuity and shorts to ground. All is good
2)I have pulled the entire engine harness, unwrapped it and inspected each wire.
3)Have substituted known good coils, icms, dist pick up coils, and ecm's, with no spark still.
4)Only little bit of progress I made was when I reversed the pick up coil leads. All of a sudden I now have injector pulse & fp runs with dist shaft turning.
5)When I put pick up coil leads back to original position, injectors and fp still run when dist shaft turns.
6) Made sure all ground wires were hooked up and good ground. As well as all power wires.
7) With key on there is B+ to coil, out from coil to icm, and out from icm on white control wire.
8) problem is icm is not switching on & off.
From what I've read, this system is a bypass type that should give spark without any est control from ecm. Yet, no spark.
Any suggestions or ideas would be a great help as I'm ready to find a witch doctor to drive away the evil spirits. I have one more test I will try tomorrow. I have made a replacement 4 wire est circuit to run from dist to ecm. I will try that.
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