Well it turns out my GSR swap is almost complete. I have everything except the P72 and I have a 2000 Si ECU the P2T which was supposedly used with the GSR but only 2 of 3 plugs go into the ECU....I was thinking if it was diffrently from OBD2A to OBD2B it wouldnt even work period I have pics upon request let me know guys in a quick bind and I need the car running by tonight.

 

TTT

 

What year is the Car? You are probably correct about being a difference in OBD2a vs. OBD2b
We offer the conversion harnesses, have a few instock and are in MD, we might be able to help -just not "tonight" -but soon.

 

So Im sitting here thinking to myself if the engine is OBD2A it WILL! plug into my D16Y8 ECU which is also OBD2A and it will be able to run. I try and NOTHING fits, only one of the supposedly 3 plugs into the ECU. Turns I hook up my ECU to the old engine to see how the fitment is and there are 4 plugs, A green one which connects to the car. Well problem is the wiring of the GSR is whacked out that it has only 3 inserts including the green so only 2 of the 3 plugs are there. I really dont know what to do.... is there any way I can just rewire this. I have the wiring of a 2000 Si if that would help anyone. Of course this sounds so plain and stupid when I can easily buy the conversion harness but I definately dont have $150 to spend nor the time to wait for shipping. I need the car done and finished any input would help.

 

It sounds like you are using an OBD2B engine harness in a OBD2A car. If that is correct, it wont work. You need to use the wiring harness that came with your stock engine. Post more info please.

 

Ok yes I am using the GSR's wiring harness into my Civic's OBD2A body and Im trying to use a OBD2B ECU CIvic Si and I dont have money. But dont mind soldering 100 wires because I just dont have the money.

 

I have the Civic's Si wiring harness free from my friend but it seems that the main harness has been cut off. I can post pics if you guys would like.

**** Problem is by trying to use my stock wiring from the D16Y8 or OBD2A it will not fit into the 99 Si ECU.

 

It can be done. Unfortunately I don't know how to do it. When I bought my 97 civic ex it had a 99 si engine in it using the stock si ECU with only two plugs in it. The B and C plug. There was some ghetto wiring done under the dash and engine bay with speaker wire but it worked for months and months without Vtec. Anyway, just wanted to let you know that it is possable. If you are unable to use an OBD2A engine harness I will pray for you.

 

OMG this is the same thing....Only 2 plugs go into the ECU. Im willing for the ghetto *** wiring LOL. Im sure we have some people in here that have done this before or have experience with this.

 

TTT

 

Anyone with any diagrams?

 

You might find some info at http://technet.ff-squad.com/ that will help you.

 

Guys im a little confused on this is going to work. From what my friend told me who sold me the engine, the engine was ran with a Si ECU. Now my friend has given me extra wiring from the Si but problem is that the wiring was cut and I believe put on to the engine and it is missing 1 plug which would be A. B and C are going in which happen to be the colors of Blue and Gray which are I believe B and C. Now my question is for the green plug on the outside of the ECU from the wiring of the engine it only has about half the wires going in as the receving end(car) actually has. Now I dont understand If I should like use my 97 OBD2A Civic Wiring on the engine and wire the connectors of the OBD2B plugs to wire up to the ECU or what? Any input would be great. I am sayin I just need a jump start on how I should do it..and I will get diagrams of everything and connect them.

 

Any chance it would work if I use my 97 Civic wiring and then try to buy a OBD2A P72?

 

TTT Im sure there is some guru in here

 

What happened to HT's helpful insight.

 

up

 

The Si harness will not work in your car without changing the dash harness, floor harness, sunroof harness, and trunk harness. Maybe even more stuff. NOT WORTH THE TROUBLE OR MONEY!! You need to use the engine wiring harness that came with your car, not the one that came with the engine. You should be able to use an OBD2A ECU that is setup for a DOHC as long as the plugs are the same. I just bought an OBD2a to OBD1 conversion harness ($100), chipped p28 ($200-$300) I did have to extend the VTEC wire on the engine harness so it would reach. That took me all of 5min.

 

The P72 and your D series wiring harness should work.

 

OBD2a vs. OBD2b yes you are correct the plug ins are different. Get a conversion harness