So after swapping ecu's and injectors and still having the #3 injector firing uncontrollably... its obvious the problem is in the wiring.

Those of you have done wire tucks would be the most help in my issue..

The injector signal wire comes out of the ecu, goes through the firewall right there, comes out and runs along the firewall just under the intake manifold, runs along the frame on the drivers side, goes up to the fuse box. Are there relays or fuses or anything in the fuse box it runs through? Then out of the box, over to the injector resistor box, then finally to the injectors?

Or am I way off?

 

I don't have an evo, but I did do a wire tuck on a evo 8 harness, and IIRC there are no fuses for the injector. what causes the injector to fire is when the ecu commands it to, the ecu itself allows the transistor (PNP or NPN-can't remeber which one exactly) goes to ground. The injector will always have power, the ecu applies or removes ground. Does the injector randomly do it while just running? or is the car moving?

 

Start car --- injector just FLOODS cylinder..

 

oh ok. this is what you can do. remove the injector plug, and disconnect the ecu. what you want is pin 2 for your injector #3. now, with the injector clip removed, you need to use a ohm meter and meter from the ecu pin #2, and the GROUND side of the injector clip. If you set it on the diode setting on the meter, WHEN you have continuity if should make a steady beep, which it should. NOW, removed the ecu side or injector side lead, and then with one lead in the ground pin on the injector side, go through and shake, twist, move the engine harness. IF the wire is grounded to GROUND you should hear a beep, and then you will have to go through and deloom and find where it is at. hopefully it makes sense, kinda hard to explain i guess

 

That sounds absolutely terrible to have to do... the delooming part -- haha

 

sorry bro

 

Happens -- I wonder if there's anyone in the tri-state(Pittsburgh) area that specializes in wiring.

I talked to a local shop about it and they said -- hell no; take it to the dealer.

 

I do! but thats my job. If i were you, wire up a ground just to see if it fixes the issue. Run a new wire from the ecu to the injector. Its worth a shot, not that hard, and if it fixes it, you know what the issue is then, a bad ground wire for the injector #3! good luck