wiring help!!!

[hemiracin03]

I am swaping in a B16 into my 90 hatckback. I got the b16 harness on the motor but the ecu harness is factory. I figured out the VTEC wiring but the only one I dont seem to understand is how to wire in the o2 sensor. It only has 1 o2 sensor to wire in . It cant be to hard can it?

 

[b16efhatch]

the secondary o2 sensor should wire up to pin C8 at the ecu you have to run your own wire from the O2 to the ecu. What model of car did it start out as? SI DX ?