I just istalled a b18c5 in my crx 89 and i dont have any o2's. I'd like to know if any honda heated o2 are compatible with the engine. And do I neet the secondary o2 absolutely ...

Thanks

 

What year ECU are you using?

That makes the decision for you. one or two O2 sensors.

 

If you are running one of the non-OBD's such as the PR3 or PW0 then I would wire them both in... Running 2 new wires isn't that hard... When i dropped a B16 into my friend's 88 CRX I had a few problems with it at first.. After swappin the O2 wires around everything worked fine, didn't think having them backwards would even make a difference. I have seen people just wire one up but I would take the extra time to do two.