Im putting a b20b into a civic eg. Ive got it in and now im just putting the final touches on it. Its obd1 and i was told that i didnt need an 02 sensor. I was told to block off the 02 sensor hole. I am thinking that i need an 02 sensor even though its obd1. Any suggestions?

 

You do need it, unless you're running chipped ecu then they can disable it

 

You need the upstream O2 sensor. You might have been told it didn't need a downstream sensor and got confused.

 

^ Correct. You do not need the sensor AFTER the converter.