SR injector not firing, getting +12v and shows continuity to ECU? WTF

[Anto]

Alright, I'm helping a friend out with his SR wiring and there's an odd problem we're having.

Motor is a s14 Zenki SR with a Nissan remanufactured ECU.

Injector #1 isn't firing. There's +12v going in and there's continuity between the ECU and the injector, so I know there's a power and ground.
We pulled the injector clip out while the engine was running and NOTHING.

-The injector is good. We originally thought it was the culprit and replaced it with one from a low mileage, working SR motor. Tested within FSM spec, 10.2 ohms resistance. We attached to a 9v battery while it was on the car, and it started to bog & smoke started pouring out, so I know the injector isn't seized.

-There's spark, I tested the coilpack and I can see the huge spark grounding out to the motor. I replaced it with a working one just in case.

-I removed the coilpack and cranked the motor, and looked inside the cylinder. No fuel on the cylinder or on the plug.

-Injector plug & harness look fine. No bent prongs, recessed terminals, nothing. I tried wiggling it while it was running and still got nothing.

- I ghetto rigged some wires directly from the plug to the injector, but it still wasn't firing. I don't know if it made a connection, but i'm going to try that again later.

WTF is the problem? It seems like it would be in the plug but I'm getting nothing.

[seven.62]

ecu or wiring might be the cause, the injectors are always supposed to have 12v, they just need the ecu to send the ground signal for them to fire, check the ecu pin out to see if the ecu is sending the signal to it. you can do this with a multimeter while your friend rotates the cas. while turning the cas you will har the injectors clicking. key must be to on position but not running

[tunersedge]

did you ever fix your problem? it seems im having the same problem with my s13 sr20 as we speak, Injectors are good, coilpacks are good, and i have continuity to the ecu.

the problem arose when i was driving home one day, car out of no where started to misfire...

if you fixed your problem, what did you do?

[shmiddy]

... correct me if im wrong but should't the injector drop all 12v.. do a voltage drop test

[shmiddy]

and continuity issnt the best way to check a circuit cuz 1 strand of wire in a fucked up wire can cause continuity.

[SoguRacing]

maybe the ecu has a bad driver?

[!Zar!]

Since you already checked and tested the Ecu, it must be the fuel pump.

[Anto]

negative

i fixed my shit, it was the ECU at fault. showed continuity and everything.
however, I don't think ECU's just go bad while you're driving. who knows.


I tested the injector with a 9v battery to see if it clicked while the engine was running, engine started to smoke and smelled like gas, so I knew it wasn't physically clogged.
I then rigged up the injectors so that #1 would fire the same time as #3 would from the ecu. I know the firing order is off, but after I tested that, motor went stable and stopped misfiring at idle, singling out the ECU.

new ecu fixed it.

[tunersedge]

Did your car start misfiring while you were driving it?

[Anto]

nope, faulty ecu from the start

car wasn't mine