No spark

Did you check for proper fuel pressure and injector pulse, engine cranking? I understand, you said no spark, just trying to see if your missing anything else?

Your vcm tells the ignition module what to do on the white ic timing, should be a dc pulse, engine cranking.

Can you check for applicable trouble codes? To check codes yourself, at the least, you need an obd2 code reader. Does the distributor rotor move when you crank it?

Hi,

I have no spark at all. I've replaced the coil, ingnition module, crank sensor and cam sensor with no luck.

Previous to this it would run fine as long as you started it every 12 hours or more often. If you went over that time it would start but you would have to crank on it forever finally starting it. I would then run real rough like the timing was off for about 30 minutes and then smooth out and run perfect but if you wait beyond 12 hours you are in trouble.

Thanks for any help you can give I'm out of ideas. Very weird problem, please help

No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,distributor pick-up coil, ignition control module, cam and crank sensors- Note: If it doesn't apply disregard it

will lack of fuel pressure shut down the ignition system on a 350 suburban.

will lack of fuel pressure shut down the ignition system. Negative

Well ...I went in to town and bought a fuel pressure gauge and tested and have no fuel pressure. I thought this might be the case since I'm not hearing the fuel pump at all when I turn the ignition on.

I did test for 12v at the coil and there is a full 12 v at the coil.

I have no spark this is why i asked about them being tied together...coincidence I don't know, maybe you could shed some light on this.

Should I replace the fuel pump or should I test something else. I tried finding a wire harness at the tank but couldn't find it....probably on top.

Anyway I appreciate your help

Thanks

Find the fuel pump connector power the gray wire direct from the battery positive post-did it come On?

Harness to cks good. Harness to coul reading good harness to icm low but reading. Does the bracket for the icm and the coil need to be grounded to intake to fire spark?? All I can thjnk of left to check is replace icm harmess, somewhere in wiring in column ignition or PCM. Can't spark to drive to run scan tool live too fat from town!!!

Found the gray wire powered it up from the battery and nothing. Are we talkin bad fuel pump?

Thanks again

it shold be bolted to intake but I've seen them run without it. you have to scan to find out what is wrong with engine sensor wise. check fuel pressure with a gauge as well and check fuses under hood. also if this has the flat style dist cap they go bad and cause your problem.

Yes sir-if the ground side is good to go. You're running it direct w/o the fuse, relay and OPSU should come alive