LS7 suddenly won't start...

[OKGMC4]

It's my brother in laws 64 vette. Car has ran and drove for months now, but the last time it was shut off it won't restart. Checked and no coil fire and with a noid light, no injector fire, but they have 12v. Computer seems to have 12v and the scan tool shows rpm while cranking so it would seem the crank sensor is working. It's like the ignition switch isn't giving the ecm the go ahead, but the all the wires on the switch are tight. Everything else including the fuel pump is trying. Any ideas?

[clinebarger]

Im guessing No codes?

Check ALL ECM grounds.
Check ALL Fuses.

If all this checks out, You will need to check the ignition hots to the ECM, I will need to know what ECM you have.

[ProStreet68SB]

Check the cam sensor?

[clinebarger]

Originally Posted by ProStreet68SB

Check the cam sensor?

That did cross my mind....But Ive seen gen III & gen IV engines run with unplugged CMP sensors, Hard start & CMP codes maybe.

[OKGMC4]

Originally Posted by clinebarger

That did cross my mind....But Ive seen gen III & gen IV engines run with unplugged CMP sensors, Hard start & CMP codes maybe.

Oops, you beat me to it!

[OKGMC4]

No codes. Fuses check fine. Says he's checking grounds right now. If it were the ECM, it's whatever Street and Performance sold him when he bought the crate engine. He swears the 12v signal is going from the ignition switch to the fuse block, but I thought it went to the ecm direct? If not I still think he needs to check where it comes out of the fuse to the ecm. Hopefully the ground thing will be it (the simple fix).

I thought you could unplug a cam sensor and it would still run? Like crap of course, but shouldn't it still start?