I'm just in the middle of putting my car back together after putting in a jspec motor. I re-wrapped all the wiring harnesses and am cleaning things up as i go just taking my time. My problem, i found today, when i went to hook up the injector resistor relay, there was nowhere to plug it into! I'm not too certain but i think that plug is supposed to be on the engine wiring harness right? well, its not.

So i was stressing abou this today and i went back to look at the pictures of my car when i was taking it apart and... It turns out, the resistor pack was never hooked up- the plug was just out there, floating in the breeze even the first time i took my intake box out. My car is an s4 TII- what is going on, am i missing something?

 

maybe there were resistors on your old injectors soldered on or maybe the person before you upgraded to high imp injectors

 

You have the wrong Emissions harness on your car for low impedence injectors.

Is this a JSPEC emissions harness? If so, beware.

 

No i'm using my usdm wiring harness on the jspec motor... I compared the injectors on my old motor to the jspec ones and theyre definitely the same. I cant figure it out at all. HELP! I guess i could try to get it running without it, but i dont see how that would even work.

 

check the resistance of the injectors using a mulitmeter

u can cancel the injector resistor pack if u have high impedence injectors

or just wire new resitors in line..

 

I checked them and both my original and jspec injectors are low impedence. Sigh... So i guess i have to wire the resistor pack in order to use my injectors? How would the car have ever been able to run without the resistor(It didnt run when i got it but it had obviously not been worked on since last time it had run)?

I guess i should be asking how now, can you just get individual resistors and wire them right near the injectors rather than tracing them and re- wiring the stock pack?

 

Anybody?

 

I really need help or suggestions here... What does the resistance need to be through the wiring harness? I think i'm gonna find a diagram for all the pins on the ecu and test from an injector plug to the end of the wiring harness to see if there are resistors that i cant see wired onto the harness.

 

As you've already been told, check the impedance of the injectors with a DMM.

If your old engine had low-imp injectors it simply wouldn't have run without the resistor pack, as the injectors would have no power. This says to me you have high-imp injectors and never had a resistor pack to begin with. If you're using the same harness as before, and the injectors on the J-spec engine plug striaght into that harness (meaning they're the same impedance), then it should work just like it did before.

 

I was thinking all those same things but i DO have low impedance injectors and my wiring harness DOESNT have the wiring for the resistor pack. The resistor pack was just sitting there. Does anybody know what the resistance needs to be for the whole setup(injectors + resistors)?

 

IF this car is a 87 and built before june of that year, it should have had a solenoid resistor and the plug on the harness for it to plug into.

Someone has put a post 87 1/2 EMISSIONS harness in the car.

Here's a simple test. Turn the key to ON. Go to the small plug on the ECU. Pull the small plug and see if there is 12vdc on pins 3C, 3E, 3F and 3H. IF it is there, then the car shouild start. IF it is not there, you have some work to do.

There is NO OTHER COURSE TO TAKE other than guessing, changing parts for no known reason, stumbling around and getting nowhere.

I'll compare say a 88 emissions/front harness with a early 87 to see if it is possible for the injectors to have 12vdc. Later.

 

I just looked and compared the 88 and 87 FSM. It's plug FEM-02 on the 88 and the X-16 on the 87 FSM. Same plug just different names.

The injectors should have 12vdc and the pins I mentioned should have 12vdc. Of course the resistors will be missing and you need to put something inline with them. The car will start without them but sooner or later the drivers in the ECU will go kaput (just a guess). But the car will start up. Double check what I just wrote by going to the ECU and checking the pins on that small plug on the ECU.

IF you had ever taken a Solenoid Resistor Package apart you would see two block resistors with 2 X 6 ohms written on the sides of the two blocks. You need to go to Radio Shack and get four 10 ohm resistors. They will look like white rectangular blocks. Never had to do that myself. Heck, if I had a Solenoid Resistor Package, I'd use that.........or would I???? One input wire and four output. Hmmm. You'd have to install them before the injectors i.e. prior to the ECU. Yeah mabe not use the Solenoid Resistor Package. Go RS.

 

You pretty sure it's a turbo harness and not a n/a???? It will matter due to other pins in the FEM-01 and FEM-02 being different in the two type cars.

I'd guess if it has a plug for the twin scroll solenoid and it looks stock and not cobbled up, then it is indeed a turbo harness and other than the solenoid resistor the rest is ok.

 

Thanks for all that! Yeah the rest of the harness is fine. I ditched the twin scroll but the plug is still there, just the missing resistor plug is the only problem i've had. So 10 ohm resistors will do it- where do i wire them exactly? Do i just find the wires on those four hot pins you mentioned and wire a resistor onto each of them? Suggestions for placement- i know resistors get pretty hot, so i need to find a well ventilated area while still looking decent, hmm....

 

Does anybody know whether i need 50 watt or 10 watt... i went to radio shack today expecting there to only be one type of 10 ohm resistor... also, does it matter whether the resistor comes before or after the injector?