So I'm getting pretty close to giving up with this thing. 2004 SS with the L67. It will crank, but won't start. Has the correct fuel pressure at the rail, but no spark. So far I replaced the ignition cylinder because the passlock sensor was bad, the ICM because that tested bad, and the PCM because the processor was fried. Same results. Crank, no spark/no start. Only idea I have is the coil packs at this point.

EDIT: Just tested for spark at the coil packs. Have no spark on any of them. Gonna bring the new ICM to get tested tomorrow, and if that is fine, gonna grab some new coil packs. I just have absolutely no clue what it could be if it's not them.

Any chance anyone has a diagram of where everything goes from the battery to the plugs? Not having any luck finding one.

 

I found a wiring diagram, didn't help much. It's throwing no codes, so I'm pretty much stumped here.

 

When you replaced the PCM, was this a junk yard donor? Was it programmed for your VIN and the security re-learn completed?

What codes are you getting? If this is a donor PCM and the codes were not cleared, you may be dealing with codes from another car.

 

Brand new PCM, had it programmed and everything. It's throwing no codes, which is what's throwing me off.

 

Sorry, I misread, I thought you said it was throwing codes. My bad.


By chance, when trying to start it, is the security message showing in the "message center" on the instrument cluster?


And just curious, what method did you use to test for spark?

 

Security was showing before I did the security relearn on it. I tested for spark at the plugs with a screwdriver, and at the coil packs with a wrench. Neither one had spark.

Stuff I've replaced recently:
- Cylinder head for 2, 4, 6 (was cracked)
- PCM
- Ignition Cylinder
- ICM
- Plugs
- Plug Wires
- Gaskets for LIM, Head, Supercharger to Intake, and Supercharger to throttle body
- Coolant temp sensor
- Thermostat

 

I would have thought crank sensor, but with no codes it's hard to diagnose. Are you sure the security relearn was done correctly?

 

Yeah, prior to the relearn it wouldn't crank. Now it cranks, but I get no spark at the coils.

 

May be way off, but have you conformed the timing chain is ok ? Have someone crank the engine over and look through the oil cap at the rockers arms and see if they move.Just throwing a idea out there, because if the cam isn't spinning you won't get spark.

 

Probably the crank sensor or a bad ground/chewed up wires from the ICM to the crank and cam sensors.

Timing chains in these cars don't fail notoriously if kept stock, but it could happen.