Thread: Running front o2 in place of rear o2

Is this ok to do or will it piss off the pcm?

Seems far far too back if you ask me.

If that what you mean.

I just mean the sensor itself the front used as a rear but plugged into the rear

Compare part numbers you noobs.

They are different numbers but I didn't know how bad it would piss off the pcm

Might be the same sensor, but the connectors are different.

same sensor, connectors are different and are crimped stainless wire so youll have no luck modifying it, which means you get to cut up your oem harness and splice on a front O2 connector after you grab a pigtail off a junk car.

so you just spent an hour or more to reuse a 40$ O2...and if its got about 50k or more miles on it, consider it junk and move on...

I'm just trying to do some diagnostics on my car and had a newish front o2 laying around

take a note of which wires go where in the factory connector
yank out the pins and connect them directly and wedge them in place with slivers of wood/straws/coffee strikers, and you should be able to make it work while still being reversible

Ask me how I know

Ps McDonald's straws work great if you slit em and wedge em together into an "atomic + sign"

but for most diagnostic purposes if your base tables are fairly well tuned all you need to do is unplug the o2 sensor and see how it runs after disconnecting the battery or resetting trims.
aside from the obvious physical damage to the body of the sensor most damage tends to be contamination and skewing of the stoichiometric mv point or heater failure.

I haven't had a rear o2 for almost a year and was just trying to see if made any difference with it hooked up.

Rear o2 will not effect how your car runs. On some foreign cars having an emissions code will disable cruise control but other then that it does not effect our cars.

Yes it does, cars with cat tests can affect how it runs.

I have tuned the rear o2 out of 5 different 3800 powered cars now and the worst thing I have seen is the pcm commanding it rich under cruise for a minute and then returning to normal on a 2004. I never understood why everyone was so worried about it.