2007 e38 cranks, no spark no injector pulse

E38 cranks no start. Factory ecu on 2007 suburban 2500 6.0/4l80e no spark and no injectors firing. Has cranking RPM and fuel pump is working as it should, have pressure at the rails. I got the truck missing drivetrain and wiring and modified a 2007 1500 5.3/4l60e engine harness to fit. Ecu is original to the suburban and HP tuners confirms this matching vin.

Fuel pump some in tank pump and tune is changed for no FPCM already when looking over tune.

All 3 grounds are in place on harness, coils have 12v keyed and good ground, injectors have 12v keyed.

Any ideas what to check next? This gen4 is new to me, always worked with gen3 on modifying stuff.

Here is everything I did to modify the harness

https://docs.google.com/document/u/0..._U/mobilebasic

If it were mine, I would run down the no spark diagnostic flow chart. I think it goes without saying but, it's most likely gonna be a wiring issue.

Scan for codes.

Watch scanner for RPM signal

Where is this flow chart you mentioned? That sounds like a great next step.

RPM it has cranking, no codes per HPtuners which I do find odd.

No codes.
When cranking I have;
Rpm is showing 125ish cranking
Cam count going up as cranking
Fuel cut type: none

Got it started, somewhere the grounds to the coils is lost in the harness, overlayed grounds and fired right up. Black wire in main coil plug to a ground overlay.

Quote:

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Originally Posted by mahoneybags21

All 3 grounds are in place on harness, coils have 12v keyed and good ground, injectors have 12v keyed.

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These scenarios usually keep me up at night. Hopefully it's fixed, but after a statement like this and then you saying all you did is add a ground and it's fixed, makes me wonder if it's an intermittent issue.
For the meantime, go play with it close to home and have some fun.