O2 sensor orientation

[Slowstang96]

Stupid question, does the placement of O2 sensors matter (front to back?) When I put my prochamber on, I laid them out in the correct order, but some neighborhood kids came by and one of them moved them while I was under the car. I replaced them by color, but the front driver sensor doesn't reach. I just taped it up until I could get an extension. I thought only 04's had length issues, I've got an 03. The car could be running worse because of it, but I can't tell because of the exhaust leak (whole nother story.) So is it possible that I just got them crossed? If not, cant I just splice in some wire to extend (less than an inch needed) any idea what guage wire?

 

[jstreet0204]

Other than the harness, the o2's are exactly the same. Front, rear, left, right, they are all the exact same 4 wire o2 sensor. That is why you can buy universal o2 sensors that you can cut the harness to the length you need.

 

[sgarlic]

I would switch the correct one back (the one that reaches.)

I have read lots and lots about sensors, and I seem to recall Randy mentioning to not switch them.

I would also think that the PCM compensates for wear differences in them, so it would apply whatever it has learned to whatever sensor is in there, unless you reset it.

 

[RandyStinchcomb]

I would switch the correct one back (the one that reaches.)

I have read lots and lots about sensors, and I seem to recall Randy mentioning to not switch them.

I would also think that the PCM compensates for wear differences in them, so it would apply whatever it has learned to whatever sensor is in there, unless you reset it.

yes that is correct, O2 sensos (ahead of the cats) and O2 monitors (aft of the cats) should NEVER be swapped around. be extra carefull if you do the cut n' splice as any mistake in soldering will effect the O2's performance.

 

[jstreet0204]

yes that is correct, O2 sensos (ahead of the cats) and O2 monitors (aft of the cats) should NEVER be swapped around. be extra carefull if you do the cut n' splice as any mistake in soldering will effect the O2's performance.

I disagreed with you the last time you posted this and I'll dissagree with you again. The o2's themselves are the same. The ONLY thing that differs is the length of the harness. I have switched out my o2's front to rear, and they function exactly the same and used wideband data along with datalogs of the o2's to verify. Unless someone screws up the wiring they will not have a problem.

 

[RandyStinchcomb]

I disagreed with you the last time you posted this and I'll dissagree with you again. The o2's themselves are the same. The ONLY thing that differs is the length of the harness. I have switched out my o2's front to rear, and they function exactly the same and used wideband data along with datalogs of the o2's to verify. Unless someone screws up the wiring they will not have a problem.

ok, well you do it your way(which is wrong) and we'll leave it at that

 

[jstreet0204]

ok, well you do it your way(which is wrong) and we'll leave it at that

Just clearning up the facts so people can make educated choices on thier own.

To make it little clearer as to why the front an rear o2's are electronically the same you should understand how the cats are monitored. They are monitored by checking the difference between the switch rates of the front and rear o2 sensors. If the switch rate of the downstream O2 sensor (which normally switches pretty slowly due to the consistent gases leaving the cat converter) starts to catch up with the switch rate of the upstream O2 sensor, a "catalyst efficiency monitor failure" code is set. Therefore they have to operate the same way in order to be able to compare the switch rates.