ryanangelo212

my buddy has a 93 sol si with a b18, running obd1.
just bought a new catback for it and running into some confusion...

so, his original engine, z6, should only have 1 o2 sensor.

currently there are two, one on the header before the cat and one after the cat (i believe this port was not there originally, but drilled at a later date by a previous owner).

now, obd2's run 2, one before and after, but his has always been obd1, so it shouldnt be there.

his header only has 1 port for an o2 sensor, but im also pretty sure that an obd1 b series runs 2 o2's, both on the header.

so, should he grab a header with 2 ports (one on the ex man part and one right before the cat) or would he be okay running only 1?

egsleepercivic

obd 1 has one O2 sensor, obd 2 has 2 sensors what year is the motor ?

ryanangelo212

pretty sure its a 94, its got the old style valve cover...
dont obd1 b series run 2?

94EG8

Nope. OBD0 B16As had 2 single wire unheated O2 sensors in the exhaust manifold, but that's about it, both were primaries too.

In all OBD1 setups there will be 1 O2 sensor before the cat.

JDMAF

Don't feel like threadjacking but are all obd1 o2 sensors the same???

IE... can I take a o2 sensor lets say from a 96 dodge neon and use it... or do they read different car to car...

94EG8

They tend to be different car to car, most of the OBD1 and OBD2 Honda O2 sensors are interchangeable with each other though.

NotAJDMFanBoy

There are universal fit Denso O2 sensors online that are cheap compared to OE application sensors. I think all 4 wire sensors are the same for Hondas in this era. The one I got for a GSR was a Denso "first time fit" part number 234-4209.

Anyway, you only need one sensor. Some headers have two bungs to let you run a wide band or work with different motors. I know I've seen the O2 mounted close to the engine side of exhaust manifold and also on the catalytic converter side.