O2 sensor placement

[Junglejoe]

Anyone know the best place for the o2 sensors? Getting the exhaust done finally with new pipes from the headers back..

 

[Dirtman]

As close to the collector as possible for upstream, on the collector itself right before the flange would be ideal but if you don't wanna drill the headers, right after the flange. And as close to the exit of the cat for downstream.

 

[Junglejoe]

In the headers wont qork for me.. so after the collector it is.

 

[franklin2]

In the headers wont qork for me.. so after the collector it is.

That far down you need to run a heated sensor if you are not doing so now. It needs to get very hot to work correctly. The factory used heated O2 sensors for the same reason, so they warm up and work as quick as possible.

 

[Dirtman]

Yup, definitely heated or you'll be stuck in open loop mode for quite a while. If you're running a post 1995 engine/wiring/pcm it should already be setup for heated o2s.

 

[RonD]

And put the bung so O2 is accessible once pipes are in place

Many stock locations for upstream O2s are almost inaccessible, lol

If its a 1995 or later OBD2 computer it will also want a downstream O2, this needs to be installed after Cat converters
If changing to dual exhaust from single you just need the one downstrean O2 on either exhaust pipe
If it had dual from factory then you would need two, one on each exhaust pipe

 

[Dirtman]

And put the bung so O2 is accessible once pipes are in place

This statement is absolutely absurd and goes against all known engineering practices.

 

[85_Ranger4x4]

This statement is absolutely absurd and goes against all known engineering practices.

I am an engineer and I support this message.
If you can't put it somewhere hard to get to at least put it somewhere it can catch on stuff and rip the wiring off

 

[Junglejoe]

2000 pcm. Its at the exhaust shop now..I bought 2 new 2000 explorer o2's, They'll be closer to the headers than before.. so is that good enough?

 

[2drxploder]

@Jungle joe, are you only using 2 o2s? who did your tuning?

 

[scotts90ranger]

Technically you want the oxygen sensors at least 2 diameters past the closest bend or junction...

 

[Junglejoe]

@Jungle joe, are you only using 2 o2s? who did your tuning?

Yes.. ONLY front o2's . The downstream was deleted. Im on a "start up" tune at the moment so I get it lined out before it hits the dyno. But Bob here in Missouri @ STL Mustangs is tuning it