Lots of smart people here. Wish I could keep up.
Strongco was out, we worked on it for a day. The conclusion is the VECU is shutting the starter off. If I understand it right, the safety relay at the starter is grounded through the VECU. If the computer wishes to prevent the starter from turning, it simply opens the ground on the safety relay.
That said, about the only thing that we are seeing is an RPM reading during cranking as high as 4000RPM. So the tech started looking at the engine speed sensors. There is one on the crankshaft, and one on the camshaft, and in theory, the computer should be able to run the engine with either one working. The only way to get the engine to crank normally is to unplug both speed sensors. Of course, without a speed indication, the VECU leaves the fuel off, so no smoke.
The Tech ordered a pair of speed sensors and we will try again next week.
He is plugged in, but the crank duration is too short for his laptop to register any useful readings while its cranking. It makes it difficult to diagnose for sure.
Thanks for all the help. Those diagrams posted look a lot like the ones he showed me on his screen, so he must be on the right track.
He was doing all manner of jumping relays etc to overide any faulty component he could. Tested wiring for ground faults, ohms, etc. Speed sensors pass an ohms test, but he needs more complex test gear to really see what they are sending out.
I will keep this thread current as info comes in.