which o2 sensor do i need?

[zellis]

i have a 90 gs with a b16a2 engine. having codes thrown, just gonna buy some new o2 sensors. my question is, do i need the sensors that would go with the 99-00 si civic? or the 90 gs... i'd assume the si, but im not sure... im still learning shit.

Denso starters, alternators, iridium plugs, fuel pumps and glow plugs
or this
Denso starters, alternators, iridium plugs, fuel pumps and glow plugs

also, should both be in the header? or can i place them b4 and after the cat. im not familiar with this shit. let me know.

any advice is appreciated.

 

[AHHVTEC]

the first sensor needs to be before the cat put the other one anywere in the pipe, and any honda 4 wire 02 sensor will work, just make sure you match up the number of wires. like if you have a 4 wire buy a 4 wire

 

[zellis]

thanks man. i just bought a new header and want to know how i should set it up. also the bung in this header is right b4 the cat. some people have told me i dont need to install a second o2 sensor.. but is that right? i mean if the ecu is throwin a code becuz one is missing, wont it run rich etc. which isnt good correct?

 

[AHHVTEC]

if you motor came with two sensors its best to run both of them

 

[zellis]

i can only KIND of see one of them. not even sure if it has 2. (dont have access to a jack right now) when u do an engine swap, what determines if u are going to use 1 or 2 o2 sensors? the engine?(b16a2) the ecu?(pr3) or the car itself?(90 gs) doesnt the 00' si have 2, and the 90 gs have 1? if you or someone can please help me understand how this o2 business works, i'd really appreciate it. thanks.

 

[AHHVTEC]

if the motor is obd1 it will just have 1 02 sensor

 

[russianswty]

depending on what ecu your running. If your using an obd1 ecu, you'll need 1 4wire oxygen sensor. If your running a obd2 you'll need 2 4 wire oxygen sensors. If your running a obd0 chipped or unchipped, run the single wire oxygen sensor

 

[AHHVTEC]

note there are also 1 wire 02 sensors that are obd1

 

[russianswty]

Which obd1 came with one wire o2? Id like to know, because I always thought
they were all 4 wire for the obd1