Stupid question...should the injector connectors be plugged into the injectors when I test the harness connector?

Edit: I'm guessing, yes. I feel like a retard. I'm so bad at electrical stuff :P

 

Yes, they do.

 

Ok, I'll check them and let you know.

 

Ok, I just got a chance to check the voltage with the injector connectors plugged in the injectors.

At the wiring harness, each injector pin had 12v.

And I double checked the MS pins again for the injectors, and only 3 of 4 had 12v still.

 

With the connector connected to the ECU and with the ignition on, you should have 12V on all 4 wires - is that the case?

 

With the ECU connector plugged in, and when I test for 12v through the connector, there is not 12v on any of the 4 wires.

 

Ignition on?

 

Yes, the ignition was on.

Edit: Just double checked to be sure...and I didn't turn the key all the way the first time. Facepalm. When I turned it all the way, each pin was getting 12v.

Sorry about that.... :(

 

You are doing something wrong - there should be 12V on all 4 wires or the engine wouldn't start at all.

 

Just did another quick test to confirm my suspicions...

I connected each injector connector and poked the + end of the 12v tester into each of the unique colored wires for each injector, and they were all getting 12v with the ignition on.

I'm assuming at this point that the issue is somewhere else?

 

Did you actually do the test I suggested with the test light on my first post? It needs to be done with a test light, not a multimeter.

 

Yes, I did it. I just don't know if I was setting up the test mode properly.

 

So I reassembled everything to how it was when I had the car running right a couple weeks ago.

I started it up, and the misfire was still there, and sounded exactly the same as it did before.

I triple checked the COPs again, and each one had good 12v, ground and signal.

The interesting thing is that if I disconnected the #4 COP connector, the idle stayed exactly the same; but if I unplugged any of the other COP connectors, the motor quickly died.

Edit: Also, if the motor is idling, and I disconnect the #4 injector connector, the idle stays exactly the same as well.


Also, I pulled the fuel rail off and attached each injector to the rail with some wire and plugged each of them in. When I cranked the car, the #4 injector wasn't firing, but the other 3 looked fine.

So I switched injector 3 and 4 to see if it was the injector, and when I cranked the car again, the injector for cylinder 4 was still the only one not firing. So I can safely say at this point that the injectors are all working properly.

I've followed the wiring all the way back to the ECU connector, and all 4 injectors are getting a 12v signal while the car is idling, yet the #4 injector is not firing for some reason.

 

Sounds like an injector driver isn't working. Open the case, take a pic inside and send it to my email address.

 

Got it. Email sent.