assuming injectors are plugged into the harness, the harness is plugged into the ecu, and they are getting fuel, what other reasons specifically would they not shoot any fuel

 

What is it with all of the injector problems all of a sudden?

Well, you'd need a ground to complete the circuit. Switched on by the ECU, physically located on the rear rotor housing.

Going back the other way in the circuit, you'd need a good fuse, and the main relay to work. Then, there are the 4 splices buried in the harness somewhere that take the single power wire from the relay and *poof* make 4 for each injector...

Basically, if you have power, a good injector coil, a good ECU, and a good ground (and good wiring connecting everything), the only other thing would be a clogged injector...

 

They wouldn't fire if there was no output from the CAS to the ECU. It's my understanding though, that if you see spark at the plugs, then it should follow that the ECU will also pulsse a ground on the injecotors to fire them also......unless the drivers for the injecotors are shot.

Plus all the other stuff above. Gotta have a ground for the circuits inside the ECU.

 

Shorted or open coil in the injector.
A wiring or connector problem - Ecu pulses not getting through.
A fried ECU.
An S5 whith the long range TPS signal at ~5v so the ECU sees WOT & cuts fuel.