I just swapped a 99 Civic Si engine, tranny, etc. into a 99 DX Hatch. Everything bolted in and connected fine except I cannot find the O2 plug on the Hatches chassis to connect the O2 sensor on the catalytic converter from the Si. The hatch came with that wierd exhaust manifold with the cat built in. Please help I need to find the plug.

 

Are you talking about the primary O2 or the seconday O2? The primary O2 on the DX is at the front of the car, where the stock cat was, and the secondary O2 might be there as well. After the swap, the primary O2 needs to be at the back of the exhaust manifold (behind the motor) and the secondary O2 is in the cat and will go through the floorboard in a rubber grommet near the shift linkage. You will have to wire it to the green interior harness to get it to work and I don't have the diagrams for you. I did a write up for the 96-98 EK at http://www.jspectuning.com/6gen/ It may help you but the O2 info will be different for the ecu you have.

Good luck!

 

Your information is helping out alot. Thanks. One more question. Do you know where the harness is exactly at so Im not searching everywhere for it. If you know where I can get a wiring diagram at on the internet let me know. Thanks.