I have a B20Z with GSR head and GSR trans. The wiring harness is obd1 as i was told with a p72 ecu. I want to get a 1998 civic EX (which i believe is obd2) can i use the wiring setup i have? Or what do i have to do to make it work?

 

Use the 98 Civic EX harness. It is valuable and useful for a swap like yours. Dont use the obd1 wiring harness.

You will have to convert your 98 Civic ex harness plugs to obd1 sensor plugs so the OBD1 sensor plug you have now is very useful. Why? it sounds like your b20 vtec motor is already obd1, meaning it has obd1 distributor, dizzy, alternator etc.. And your throwing it into a obd2 car.

You will also need an ecu conversion harness obd2a==>obd1. You can find this on ebay. Everything is very simple to convert if you have the time. Good luck!

 

So do i simply cut and splice the sensors back together with the ones i need? Or can i cut and splice the whole thing all the way up to where it connects to the car on each end?

 

use the 98 ex harness the only thing you need is obd2 dizzy, alternator and a jumper harness everything should just plug and play without cut and splice.

 

ok thanks

 

Why would he want to buy a obd2 dizzy, alternator, and injectors when he can just simply cut and splice all the obd1 sensors and solder it into the obd2 harness? Your making him waste alot of money on something he can do in a couple of hours..

OP just simply cut and splice the obd1 sensors and solder it onto the obd2 harness. Its as simple as that and it wont cost you a dime!

The only thing you would have to buy though is the conversion harness for the ecu. I seen these for around $25-30 on ebay. Make sure you get obd2a and not obd2b for the conversion harness

 

ok thanks

 

qustion for raidacaipo. Can i cut the wires where the main sensors go to each end of the car and fuse box and just splice the whole thing right at each fendor so i dont have to splice every single sensor?

PS wont cost any money if i use 98 ex harness bc i have the dizzy alternator and fuel rail for both types obd1 and obd2 but i want my obd1 AEM fuel rail.

 

Wait, if you have obd2 alternator, injectors, and distributors, than I would NOT cut the harness. Just change the obd1 alternator, injectors, and distributors to your obd2 ones. Therefore, the 98 civic harness will plug right up without any modifications. However, if you plan on using an obd1 ecu, then get the conversion harness like I mentioned.

Alternator - Make sure you check the belt and replace if necessary

Injectors - Make sure they do not have broken tips and change the cushion rings and injector rings on them as well otherwise it may leak fuel.

Distributor - Make sure you do ignition timing right after you replace this.

All fuel rails are the same whether its obd1 or obd2. I don't see a difference so you can use the obd1 AEM fuel rail perfectly fine.

If you still plan on cutting your harness and converting it to obd1, then just cutting the tip of each sensor giving it about 2 inches of wire on each plug and then splice it with the obd1 sensors is the best method. Just match the colors. The only sensors your going to cut and splice are the alternator, distributor, and Injectors.

You may have to extend the primary oxygen sensor plug though on the ex harness. But thats not that hard to do.

 

I guess everyone has there own way, i like it original with out cut and splicing.

 

ok thanks both of you a lot for your help bc this is my first swap with another motor that doesnt come factory.....

also a 1995 civic EX is obd2 correct? (i figure it is bc hte sunroof and power windows)

 

NO,
All 92-95 civics are obd1
All 96-98 civics are obd2a
All 99-00 civics are obd2b

 

oh ok cool