Ok, I have a 2000 Civic EX and the motor, tranny, and wiring harness out of a 2001 GSR USDM. The GSR came in as an accident, the insurance company totaled it and I took everything out, I put my stock civic motor and tranny into the GSR and also the cvic wiring harness (soon found out I should have kept that). My question is now that I have the GSR into the civic, what wiring harness do I need to buy and also what ECU. I live in NY and need everything to work and no check engine light in order to pass emissions.

Would appreciate any help.

 

You need a 99-00 Civic engine harness. To make it real easy, find an Si harness; everything is in the right spot and just plugs in. If you want to keep IAB, you will have to add the wires for it. You can also use an EX harness but you'll have to extend a few wires (VTEC solenoid and switch) and add the IAB wiring. You can also do a DX/LX/CX/DX harness and add all of the wires for VTEC, knock sensor, IAB.

As for ECU, the OBD2B Integra has an immobilizer. You can either have the immobilizer bypassed or you can convert to obd2a and get an obd2a GSR ECU.