91 civic d15b2 with y8 head

[Geoffrey_ogden]

I have a 91 Honda civic dx that has this connector that is a 3 wire and I need to add the second connector to the 3 wire does anyone know what the wiring is i believe it’s obd0 to obd2

 

[Joshua884]

I had a similar situation when I was swapping heads on my Civic. If you are using the D15B2 with the Y8 head, the wiring harness can be tricky. The original harness might not match perfectly with the OBD1 or OBD2 ECU. For this, I had to wire in the second connector using a conversion harness to make sure everything was compatible with the OBD1 to OBD2 change. If you’re unsure about the exact wiring, it's a good idea to consult the ECU pinout diagrams or get a conversion harness specific to the OBD swap. The three-wire connector could be for the IACV or TPS sensor, depending on how you are setting up the system.