justinwazner

Hey guys, i did a little research as to what harness i should use if i am swapping a B16 and Gsr tranny out of a 99 SI into my 96 civic DX.

one guy said use my existing harness and modify it... he said ill throw check engine light because of lack of a secondary O2...

another friend of mine says use an EX harness itll do the same thing yet easier to modify to work...

and my question is, why cant i use the B16 harness with an obd2a to obd2b dash conversion harness so there is no modifying anything, it would all be plug and play..... right?

anyways i really appreciate any input considering i know a million people have done this swap. thanks!!

itsnotfast

More often than not poeple use and modify the existing harness. The EX harness would be a little easier to use as far as not having to run new VTEC wires and you don't need to extend as may wires. Although i'm sure you could modify the B16 harness to work, it's not really worth the hassle because you would have to chop up a conversion harness and mix and match wires to get it to work right. You would basically have a butchered half of a conversion harness and wasted $50.

jayWknight

iTrader: (3)

well the 99-00 si harness is obd2b and your original dx is obd2a. Both harnesses have secondary o2 senors and I realized more then half of the people have no idea what is what when it comes to wiring.

If the 99 b16a2 comes with the engine harness then use it and use a 99-00 si ecu. If not, find a b16a3 (p30) ecu from a 96-97 del sol vtec. you are going to be adding 2 wires from the ecu plug directly to the vtec spool valve and knock sensor. You will also be converting from 3 wire iacv to 2 wire iacv. The last will be 3 wire CKF sensor to 2 wire CKF. It isnt horrible to do.

jayWknight

iTrader: (3)

All the wiring diagrams are on ff-squad's technet site.

itsnotfast

While this is possible, it would be a hack job no matter how you do it because the dash harness in the car will still be OBD2A and you'll have to chop up the conversion harness to make it work.

itsnotfast

Here is a pinout diagram. The plugs are different enough that trying to have a half OBD2B and half OBD2A ecu harness will be alot of headache and really not worth the time.

justinwazner

i dont understand why i would have to "chop up" a conversion harness, isnt the purpose of buyin the conversion so i dont have to chop up everything?

yes the swap comes with the ECU and harness, so there will be no converting for any sensors correct?

and you agree with him about chopping the dash conversion harness?? i dont get why? any explanation would be awesome

and thanks to all of you seriously

speedooo

The obd2b harness will not plug into your existing main harness, your cluster and a few other items won't work...that's why you can't use the si harness.

Extend the wiring for your secondary o2 sensor, add the 3 vtec wires and add knock sensor wiring. Pretty simple.

justinwazner

so a conversion harness wont fix the issue of the si harness not wiring to my dash?

and if im using my stock harness and adding vtec and knock sensor what ecu am i supposed to run? sounds like you mean run the b16 ecu, but its obd2b and my existing harness is obd2a isnt there a difference with the plugs??

94EG8

Correct.

This is where the conversion harness comes in.

justinwazner

so buy a conversion harness to fit my harness and the si ecu is what your saying? that would ultimately make sense, now im starting to get it... where do i find that at? online obviously but do you know of a legit site that you prefer

94EG8

Correct. I'm pretty sure Rywire sells conversion harnesses. This pic should illustrate the differences between OBD2A and OBD2B Civic harnesses and why you can't mix and match cabin harnesses.