did a b16a swap, now i need a second O2 sensor...it goes AFTER the cat, right?
now i need to fabricate a bung and screw the sensor in...i have TWO wires hanging down (pictured) and a ONE wire O2 sensor...do i just cut the terminal and splice all three together?

 

no b4 the cat for a hatch or crx

 

You need a 4 wire O2 is what you need. And as has been said, not after, before the cat.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JustAnotherRex &raquo;</TD></TR><TR><TD CLASS="quote">You need a 4 wire O2 is what you need. And as has been said, not after, before the cat. </TD></TR></TABLE>

4 wire=obd1
1 wire=obd0

 

you want both O2 sensors in the header - if you have PR3 or PW0, one is wired to ECU pin C16 and one is wired to ECU pin C8

 

Not enough info man, Is your car obd0 or obd1??

You should have the o2 wiring as followed with any non chipped obd0 pr3 or pw0 ecu

O2 sensors
-----------
On a stock D15 or D16 the o2 sensor is the white round clip and its primary. If you just plug that into the new b16 with pr3 or pw0 ecu,your making the computer think thats the primary o2 when in fact it now becomes the secondary. So you will get hesitation and the car will run like crap.

White round clip o2 is no longer primary on a b16. So you need to make sure it goes to ecu PLUG C pin 8

Green oval clip is primary and goes in ecu PLUG C pin 16