Fuel Injector Wiring SR20DET

[Seedlessone]

SR20DET S13 into 89 S13 Hatch. DIY wiring, then sent off to Wiring Specialties to sort it out and make sure it's right. Harness came back good.

I've had this swap ongoing for about the past year, and still not running. I'm hoping someone here can help. We're to the point now where we have spark, timing correct, fuel pump primes and pressurizes, but we have no pulse at the injectors, thus not spraying.

Just did a continuity check from the ECU, and it seems pretty jacked up. From what I understand, we should have continuity from the ECU to each injector independently from pins 102, 103, 110, and 112, for the pulse, then the other side is ground. What we got instead was continuity from pin 112 (Injector No. 4 drive output) to injector 4 on both sides, and then also at other injectors. Sounds to me like a wiring fault.

Where from here. Help.

[MrSoutherland]

I had a similar problem and just got a new wiring harness. Of course your going to have to re-solder some of the clips from your ka harness. I know you probably don't want to spend the money on a new one, but it cancels that out as a problem.

[Seedlessone]

Has anyone ever rewired the injectors directly to the ecu running new wire?

[MrSoutherland]

I personally don't know if they go to a relay first. But if they run straight from ecu to injector then why not...Find out first though. Look in your fsm

[Seedlessone]

Anyone else do this? Im headed off to get pigtails to try.

[Seedlessone]

Turns out that the wiring within the harness is completely shorted with regard to the fuel injectors. I went to the junkyard today, got pigtails for the fuel injectors, an ECU plug with about a foot of wire, and built a new fuel injector harness from scratch, repinned the ECU plug with the new wiring, and voila, we got fuel and it ran. Just to clarify an answer from my previous question, it is very possible to rewire from the ECU directly to the injectors. One side of the injector wiring goes to a keyed 12V source, and the other side goes to the ECU 101, 103, 110, and 112 pins. Pretty simple really. Now we still have a bad #4 injector, so that's got to be sorted before we go any further. All downhill from here. Thanks for everyone's help!

[Blown240sx]

Well if its any help the way the injectors work are not a 12v trigger but a ground trigger.

All the injectors should have a constant 12v source and on the other side the ground is provided by the ecu. Same goes for the coils but the ecu uses the ignitor to provide that ground.

So key on you should have a constant 12v on the injectors.