what are all functions that could cause the injectors to cease from pulsing or 'firing'?

 

VATs or lack of distributor reference pulses (DRP).

RBob.

 

i thought vats also disabled the starter?

 

On my 87 they wouldn't fire and I found that the chip wasn't plugged in all the way.

 

my chip should be in all the way because my laptop can read the ecm just fine as far as all sensor values go.. ill double check though.
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i thought i would be smart by taking the ground before the ecm for the injectors, and grounding it myself. but could not feel the injectors clicking on or off. did i make sense? and if so, does this mean anything? or do the injectors take more perimeters to fire instead of just voltage? ohms maybe?

 

can i give a 12volt to the injectors and hear if they click on or off?

 

Yeah, if you isolate the injectors, you can apply constant 12V to one pin of each injector, and with a loose wire on the other - tap it quickly and briefly to ground to make sure they work. But, if it's installed on a car, and you're having problems, first check for 12V on BOTH sides of the injector (not cranking), and during cranking one side will briefly go to ground while they fire. I think the injectors are fused in the main fuse panel, on 2 different circuits (INJ1 INJ2, or something). Check those for 12V at key on. I don't think they're connected to the fuel pump relay for power (but the system that our company makes does). The fuel pump relay, of course, only stays on for a brief moment at key on, which could confuse you if you turn the key on, then lazily go out to measure the voltage.

 

im a lil confused here, i know with ignition on, at the harness i can read 12volts. i plug the harness into the injectors, and at the back of the motor where all 4 ground combine into one wire. i was grounding that wire trying to simulate a circuit for the injectors but no such luck. am i doing something wrong?

 

The ECU grounds it through the ground wires via the injector driver, but keeps it open when the engine is off. I'm confused which wires you're trying to ground. The pink/black wires should have power at key on. the other wires are the controlled wires. With the injectors connected, Those wires should also have power at key on (but sensed through the injectors). Grounding those wires should fire the injectors.
But, this post is probably too late, as I've seen your post in DIY PROM about high BLMs.

 

Also a high TPS during cranking ONLY can stop fuel.
"Clear flood mode"
There are settings in the bin that can be tweaked if needed.
Usually 70-80% TPS activates the function IIRC.

 

Maybe this was said before. look for the ecm fuse behind the battery. Mine blew when I got a bad fuel pump from GM. Had the same symtoms. The 12 volts at the injectors comes from the ignition Switch.

 

thanks guys for the input, howeveri ended up unplugging my whole harness, and going through it redoing it all, and when all done and over with, it fired up. thanks for the input however. we may never know what the real problem was!