My Car has no O2 Sensor, so basically it ran like **** and then shut off and wouldnt turn back on. I Have a 92 Civic HB DX, with a 99 GSR OBD-2b,with a P72 OBD-1 ECU. Im wondering if I need one o2 sensor after the cat or do i need two? ive been told that OBD-1 only needs one O2 sensor but OBD-2 needs two, one on the header and one after the cat, my header that came with the engine doesnt have a hole for the O2 Sensor. Help Thanks

 

You need an O2 sensor on the header. The ECU needs to "see" the mixture and adjust accordingly. OBD1 needs a sensor at the header, OBD2 needs it at the header and after the cat.

 

wheres a good place to buy O2 Sensors? so it has to be on the HEader? what if th header doesnt have a hole to put in the o2 sensor is there any other possible way?

 

bump

 

you can buy a o2 sensor of ebay for around $60.. denso too.. and you can also get a highflow cat with an 02 hole in it.. if not you can go to ur local muffler shop and they can drill and weld you a o2 bung on your header.. then just screw in the o2 sensor.. hope that helps