Ok i know i've been having alot of problems with this, but i can't figure it out whatsoever, and neither can anyone i know. I have a 350 with a 305 carb, TBI, and for some reason my injectors will just NOT spray. I have replaced the fuel pump(which i have to give power to myself, a whole nother problem i can't figure out), the fuel pump relay, the ignition module, i even rebuilt the whole carb(the fuel pressure regulator was disgusting). I don't know what else could be causing the injectors not to fire, the first day i tried giving the pump power on it's own, the car started, ran great....injectors worked.... then now all of a sudden the injectors won't work.... Fuses are good, all four wires going the injectors have power.... I don't know what else to do!!!! Any help?!

bump

All 4 wires going to the injectors have power? Ummmm... that's not right.

2 should have power as long as the key is on.
The other 2 should get grounded by the ECM when it wants to squirt.

If you have actually got power on all 4 leads - you've got a messed up harness issue, or a whacked ECM.


edit: quit calling it a carb. It's a throttle body.

Could the ECM be the same reason that the fuel pump is not turning on as well? I've been having to give power to the pump manually.....

Possibly, yes. It works on the same concept as the injectors (except in this case the ECM is turning on the relay that powers the pump).

I don't want to say 'replace the ECM' as that seems to be a blanket answer, but... ummm.. got one you can swap in, even if the PROM isn't dead on?

I'm willing to spend the money even if it doesn't work, used ECM probably around 50 bucks i'm guessing? And what is the PROM? How much is one of those? Where is all this located? And is it hard to replace?


And i suppose that would probably be a good reason why i'm not getting any power to any of my wire going to my fuel pump relay as well....


Thank you VERY much for all the help

The PROM is the 'chip' under the cover. Just get an ECM with the same part number (1227747 or whatever you have), then swap your PROM and calpak (the little chip) over into the new one. Or, you TRY and find the same year, make, model, engine, trans, rear end.... etc, etc.... good luck on that.

Your other statement though.... you say you have NO power at any of the FP relay contacts?! There should be power at the orange wire at all times. Grey (could be tan/wht) goes back to the pump. Grn/wht is +12 when the ECM commands the relay on. blk/wht is ground.

Once again I am lost and not sure what to do next....

I replaced the ECM, picked one up from a j-yard(20 bucks) and it was a delco reman, so i didnt have a number to match up with. But it was out of an 89 camaro...(and i did swap the PROM)

After replacing it, still have power going to all 4 wires to the injectors, still no power to the fp relay, and now i've obtained a very loud tick coming from both injectors when i turn the keys forward, or maybe even the fuel pressure regulator.....

The fuel pump still has to be given power manually, but the car still will not start.....because the injectors still won't spray

OK - cheap test. I'd just swap your 'correct' ECM back in for now.

Before you actually hook it back up though.... test for power at the injector plug with the key on.

Also... you ARE going from ground to one of the pins when you've been testing this right? NOT across the 2 pins?????

Also, did you check for power at the FP relay socket on the orange wire.... again... going from ground to that pin?