Car: 1998 Accord LX, 4cylinder automatic.

I came out one morning and my car wouldn't start. No work had been done, no precipitating event. The car cranks strongly, but won't catch. It will start with starting fluid, though. I've tested a bunch of things, and think I've narrowed it down to the injectors. I get +12v to the injectors with the key on, but when I crank the engine, there is no ground pulse from the ECU. (tested with a test light)

My questions: What should I test from this point? I should test continuity in the ground wires from the injectors to the ECU, but I don't know which ECU pins they lead to. (anyone got a wiring diagram for my year, or can point me to a relatively inexpensive one to buy?) What would cause the ECU to not output the injector pulse? Does it basically come down to a bad ECU at this point, or could it be something else, hopefully less expensive sounding?

Thanks for any help!

 

Okay, new info: I'm an idiot. The immobilizer light on the dash is continually blinking when the key is turned to On. The car has an aftermarket remote start system, but nothing has changed in that system for years. The immobilizer bypass is a DEI 555U, I think.

Can the ECU/immobilizer just 'forget' the key code for no reason? Is there a 'limp home' mode to temporarily disable the immobilizer to be able to drive it to a dealer to get it reprogrammed?