I bought an 88 FC a few months back. When I bought it didn't start. The guy I got it from said he just swapped in the engine and couldn't get it to start. Hence the reason I got it for so cheap. I really just wanted the rustless shell for a TII swap anyways. Well it took me all night of reading threads on here but I finally got it started. There was power going to the resistor pack plug and there were no resistor pack. I read that I could just twist the wires together and it would start. Well it did. So I'm guessing the guy put an 86-87 engine in with the harness and ecu. ???

Well now my question is I just bought an S4 TII engine and I was wondering what I should do about the harness. I know I should use an N/A one and I was gonna just use the one in there but.......How do you know if your gonna need a resistor pack or not for the JDM TII engines? Should I get an 88 harness or just use mine?

I would like to clean up the harness too. Can I eliminate all the plugs that I'm not using? I was gonna get some harness wrap to get a clean look. I have all the emissions removed so there are a lot of unused plugs all over the place. Any Tips?

Thanks

 

check the injector impedance with an ohm meter to find out if the injectors are HI or LO.
That will determine if you need a resistor pack or not.
The 88 version came with no resistor pack on the harness(no plug,,nada).The earlier versions had a big *** 6 pin connector to hook up the resistor pack(under the stock air box).

 

So when I get the new engine just check the impedance on the injectors, then I will be able to tell what wiring harness I can use for the swap?

 

Check impedance on the turbo engine's injectors, and that will determine if you can leave the resistor pack bypass in place, or if you need to buy a resistor pack to plug in. An alternative would be wiring some 6-10 ohm resistors in line for each injector, but that'll be much more complicated than getting a resistor pack.

The injector circuits need to have at least 8 ohms of resistance to safeguard the ECU. In '86-'87.5 cars, this comes from 2-3 ohm low impedance (peak and hold) injectors & four 6 ohm resistors (resistor pack). In '87.5-'91 cars, you just find 12-15 ohm high impedance (saturated) injectors.

 

Thanks Rocket. I just got the engine and I'm going to rip it apart and check the ohms. If it is an 88 engine, I should be fine with the 86-87 harness right?

 

As I mentioned, in the middle of the '87 model year they switched to high impedance injectors. All '88s have high impedance injectors. No '86s do, and only half of the '87s do.

 

You can Bypass the resistor pack and run HI impedance injectors if that is what your plans are.
Simply get the Resistor pack,and rig the wiring on the resistor pack to NOT feed the Resistors,,basically loop the wiring in and out off the Resistor pack harness.
This would be done on the Resistor pack wiring on the other side of it's connector, NOT the Engine harness.The Engine harness would remain untouched.
That would Bypass the Resistors in the pack all together and feed the voltage straight up to the the HI impedance injectors.

 

Ok so my injectors are HIGH impedence on the new engine. So I am just confused on what makes the injectors need the extra voltage. ECU? So I should get an 88 ECU right? Also what do you think would be better for the harness: My current N/A LOW impedence harness with wired in HIGH plugs, the JDM TURBO harness that came with the engine, or just buy an 88 N/A harness?

I don't really want to buy another harness but I don't mind if its going to make things a whole lot easier because I have a million other things to do with the swap.

 

The TII ECU sees HI impedance anyways.
The resistor pack makes LO impedance injectors appear to be HI at the ECU.(3,4 ohms plus 6 at the resistor equals HI impedance,Regular Hi impedance injectors are about 12-14).I hope you can decypher that..lol!
.OK..tell us what your Harness IS( on the car)..Does it have an injector pack on the harness or not?
By the way.,what year of engine is going in the car?

 

Haha yeah that makes sense. I was so confused with this injector stuff. The problem is I have no idea what the guy before me put in this car. When I was trying to get the thing to start when I got it I swear I checked the injectors and they were HI. Which means that it is an 87.5-88 harness. But the resistor plug was seeing power which is why I was confused. And the new engine I am not sure because I got it from JDM engine zone and they are slightly retarded. But the HI injectors makes it 87.5-88 right?