No fuel pump "prime" turning key on.

Continuation of my Optispark post.
What controls/tells fuel pump to Prime when key on to start?
Try to keep this short: Initial issue motor dies after 10 min on restart no prime key on (fuel pump will run if DME relay jumpered)cranks but no start. Let sit/cool key on prime and starts. Fuel pump tests good. DME Relay good.
Since, replaced coil and Opti (Petris). Same issues, confirmed 12v key on power at both Coil/ICM plug connectors, but no spark from coil or plugs.

NOW no prime Cranks no start (with jumper FP runs) no start period. Cold or hot.

This website is excellent for LT1 troubleshooting info if you haven't seen it yet. It has helped me out a lot.


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as i said in your last thread, you need to get a scan tool hooked onto it. first off, see if you even can get communication with the ecm, and then look at the data stream and see if you have a crank signal.

im gonna take a wild stab and say your either losing 12v or a ground to the ecm.

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Still waiting on pcm scan. In the meantime I've been using above site for testing/troubleshooting. Currently recheck
" key on" ICM and Coil harness plug tests no voltage? when I had 12v days ago. Visual inspection of wiring from connectors back into harness nothing obvious (removed tape on connections). Found something strange, to me, there is a common green wire connected to ICM/Coil traced within harness cover back thru firewall to pass footwell pcm location. It has a spade connector but not connected to anything, I noticed this was like this since buying car and 6+ months of driving prior to current issues. There is a porsche harness 2 prong molex (red/red blk) spade connector fits. WTF