Zedn I am going with a 2009 G car and LS3 motor.
all the fuses are good and you have power and gounds on all ecu connectors. Battery voltage above 12.0 volts.
Lets start with cam shaft, 3 wires A is 5.0 volt power, spec is 4.8-5.2 volts anything outside this, bad wiring of ecu internal problem. We go with good readings. test. remove CMP sesnor from motor. Wires are hooked up. I hope you have a tech2 or top of the line scanner or this is going to be a problem Your scanner needs to show the count of the camshaft sensor. What we do is run a piece of steel across the sensor and you should get 1 count on the scanner. If not back probe "C" terminal with a good volt/amp meter, (digital) on low dc voltage and want to see a spike when you run the steel acroos the sesnor. Ign is on when testing. No signal bad sensor. Look inside hole where sensor comes out of aND CHECK FROM DAMAGE. should see slotted pin wheel. crank motor and make sure it move with breaker bar on crankshaft bolt and wheel is not loose. If this test passes going to crankshaft sensor
How easy is it to see and work on? Pull header if needed.
Crankshaft sensor. same as camshaft sensor for wiring. "a" is 5 volt from ecu, spec 4.8-5.2 volts anything else, test wires with load test and if pass replace ecu. wires OK same test wire"a" 5.0volts, wire"b" ground back to ecu. Make sure on both of these grounds to test with ecu connector unplugged for resistance. It's possible a wire rubbed through and is hitting a grounded part of the car frame and getting a faults ground. check both ways. OK wires are good we need a varying dc volt reading from sensor. If your scanner is good we should see a count number as you run a piecs of steel across the sensor.
You said you have an rpm reading so I think this sensor is ok. May sure the reluctor wheel is tight on the crank shaft. This covers the test for the ign system.
Couple of side ideas, Does your motor have a VLOM? Is it still operating or removed from the system?
OIl pressure switch is working and you have a reading of pressure. Should know that this switch doesn't give accurate pressure readings. There are 3 or 4 micro switch inside that are on or off and GUESS the pressure reading. YES Guess, you might want to add a direct line to a gauge. Some motors will shut down with no pressure, crank and stall. prevents more damage to motor.
I am starting to think either the ECU is screwed and in lockout where you can't get the car to run and will have to replace. Reason here, it controls both base spark output and injector fire. YOu have neither. Other check is igntion module. Go to junkyard and get a couple of spares that match the numbers on it, (8 digit) and try for a test. Motor runs, bad ignition module doesn't run back to ECU. Final note, YOU can't reprogram an ECU if it's locked out. YOU can't unlock it either. I talked to GM engineering on this on friday. You can add or remove info but once locked it's a 1 pound piece of junk
There is a way to batch fire all the injector or coils I will have to look this up if the tests above don't work. Good luck Zed. PS WHERE'S GAV??? I have better than 30+years with GM as a tech GAV> Paper work out the A$$ Where are you?? You should have this car running allready or at least giving the info I gave to check the 2 sensors. Very disappointed in you. Do you think this is more wrong info?? THis comes straight for the GMSI website. I shorten the tests and made simpler for Zed. Thanks for all your help.
Rick