Thanks for the responses guys and sorry for the long delay in this response.
The car is still not starting.
I acquired a copy of HP Tuners and have spoken to GM Performance Tech Support several times, but so far, everything we have tried has not worked.
The car sometimes throws a P0341 (Camshaft sensor) error and sometimes throws a P0016 (Camshaft to Crankshaft correlation) error, but all of the diagnostic checks pass, except for removing the engine and inspecting the timing chain. If the engine ran before leaving GM, then the timing chain shouldn't be the cause of the problem. However, one GM tech support person said that they run each engine before leaving the factory and another GM tech support person said they don't.
The easiest thing at this point is to replace the computer and hope that the fault lies there. Jeg's is sending me a replacement to try. If that doesn't work, then the next step will probably be to remove the engine and inspect the timing chain and the physical gear-end correlation of the crankshaft to camshaft.
In response to some of the other comments:
- The wiring for both coils and injectors has been double-checked by color code and cylinder position against the GM wiring table as well as a running Corvette.
- I have tried starting with the MAF unplugged (limp-home mode), with no effect.
- Spark plugs/coils/leads on both banks have been tested by pulling the spark plug and grounding it against the block while cranking to confirm a healthy spark.
- The butterfly valve on the intake is cracked open for starting and moves when the gas pedal is pressed. I have tried starting while pumping the pedal.
- HP Tuners shows an increment in the Camshaft Active Position Counter when I pass a screwdriver over the end of the Camshaft sensor, which seems to confirm that the sensor and wiring is correct through to the computer.
- HP Tuners shows the gas pedal position changing when the pedal is depressed, so the pedal sensor to the computer appears to be working correctly
- You can smell fuel when cranking. Fuel vapor was ejected from the cylinder when the spark plug was removed for the above plug/coil tes, so it's getting fuel and a previous noid test showed the injector firing at regular, expected intervals.
- I'm pretty sure there isn't a short in the ignition circuit, given that the plugs spark when held against the block. Even if there was a short between a couple of the cylinders, at least one should be firing at the right time, which would give better results than I am seeing. I'm also pretty sure there isn't a short in the injection circuit, as the noid tester flashed regularly when cranking and the short would have to affect all the cylinders to produce the current results.
Bottom line: I'm getting fuel, spark, compression and air. The DTC's are indicating a timing of spark issue and that matches what I am seeing in terms of extensive cranking with the occasional "phhhttt" as something tries to fire out of order and momentarily stops the cranking (loading up the starter motor with physical resistance).
The only thing left I can think of is a computer problem or an internal (e.g. timing chain) engine problem. Hopefully I'll be able to do the easy one (computer) in the next few days. If that doesn't work, it's time to pull the engine. If that doesn't work, I'll take you up on your suggestion to call D3 Performance (thanks, Dave).