So in a GM TBI motor, all the speed reference comes thru the distributor base...when the rotating "pole-piece" aligns with the stationary magnet then there's a little impulse that goes to the ignition module...but that's the only crank signal reference. If the ECM cannot sense the crank turning then there will be no injector pulsewidth called out.
An easy way to test my theory is to lay a spark plug wire, pulled from its plug, close to a metal surface of the engine and crank to visualize spark or no spark. This can be problematic if there's a lot of raw fuel around but at this point it sounds like there's none.
The part that I would be worried about there is just the ignition module itself, be sure to renew the silicone dielectric grease under the module because it allows conduction of heat to the aluminum distributor base. I also use anti-seize on the super tiny screws that attach both the distributor cap and the ignition module. I've had them corrode before and strip the threads out in the aluminum and there was no easy renewal short of getting a new distributor base and re-timing the engine. Which isn't the end of the world but a *lot* more work than it could be to address a simple stripped thread.
