i have a 91 ef hatch and im putting a 99 ls motor in it and need to know if a 91 ef si engines harness will work with the motor.

 

You might have to extend a few wires but it should work.

Is the car MPFI wired already?

 

no i havent started the swap yet. cause i dont have a engine harness for my ls. and i didnt wanna start it til i was sure that a ef si engine harness would work on an obd2 ls motor

 

i would figure it will fit capt.

 

the Si engine harness will only work if your car is the Si model

 

if your car is not an si model use a dx harness converted to mpfi

 

As others have said, the key is taking your original harness and adding subtracting as deemed necessary. Take your OEM harness and if necessary, add the MPFI extensions and then worry about extending the wires necessary to reach relocated sensors.

 

ok thanks for the help

 

i know this is probably a stupid question for you guys but this is my first ef so i dont know much about them. but what is the mpfi that i need to wire? haha

 

If you have a DX model it will be a dual point dpfi. MPFI means multi point

f i is fuel injection

 

here you go have fun

http://www.angelfire.com/d20/hcivic88/dx-siwiring.html

 

I dont mean to thread jack but i seem to have a lil similar problem with my swap. if anyone can help out check out my profile under the bodyharness.

 

the origianl motor that was in it was a obd1 gsr. i bought my ef as a shell. so should i be good then with the mpfi?

 

atcually a buddy of mine is gonna give me a obd0 ls harness. that should work fine for my 99 ls motor right?? lol

 

It should if ur using obd0 dizzy if not get jumper or make one pretty easy and yeah extend wires get rywires for ecu jumper

 

No, you need to work with your factory harness unless you plan on rewiring the engine + chassis harness at the same time. If you are up for that, power to you, if not, work with what you have, in the end it usually saves time and energy.

 

the harness you have will work perfect. esp if it had a gsr before the plugs for the ls are all the same

 

What if i Have a 97 obd2 B18B1 ls and I have a harness for an obd0 B18A1 ls? would that plug right up to a crx si harness and the motor as well, without having to do any wiring?

 

No

 

the harness you have will plug right in and run the b18 as long as you get a obd0 dizzy, and remove the resistor box from the car. cut the wires going to ii and solder all 5 together. that will allow you to run obd1/obd2 injectors

 

Yeah i knew you had to change the injectors & dizzy wasnt sure about all the sensors, okay that makes since thanks. I have obd0 injectors i plan on running cus i dont wanna cut the harness, Do I need to leave the resister box there If I do. yes

 

yeah leave the box if you use obd0 inj.

 

[QUOTE=blasterman87;42628562]yeah leave the box if you use obd0 inj.[/QUOT
cool thanks!