# Rear o2 sensor bypass?? 1996 1.6 sentra



## tsquic (Dec 20, 2007)

I have a 1996 Sentra GXE with a 1.6 engine. I recently damaged the rear O2 sensor by backing out of a driveway with a buckled piece of concrete. I recently replaced the header pipe(s) and cat with after market from Exhaust Warehouse.com. The center pipe and muffler are after market also. Well the system seems to hang lower than the factory system and the rear O2 sensor is angled down towards the ground a little more than the original system. The lower position of the O2 sensor and the buckled sidewalk combined to physically damage the O2 sensor causing the CEL to light. QUESTION: since the rear O2 sensor only tells the computer if the Cat is working, can it be bypassed by connecting the wires together? 

Also, does anyone sell heavy duty rubber exhaust hangers for the 1996 Sentra? I have seen heavey duty hangers for VW made from polyurathane(?sp) over stainless cable.


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## 2dr_Sentra (Dec 10, 2005)

Yeah the rear o2 reads nothing more than cat efficiency. You can left it unplugged... you'll have a check engine light though. Ive been running a test pipe for years now with no problems.


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## birdsflyingover (Dec 19, 2007)

yeah, it just monitors the cat. you can't by pass it by connecting the wires(actually kind of a funny solution). it's 12 years old, run with the light on.


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## Katana200sx (May 13, 2002)

kartboy makes exhaust hanger you can use on your b14. i did the same thing to my o2 sensor after installing a catco high flow convertor. if you trace the wire back to where it goes inside the chassis, you can unplug the wire hanging outside and then pop the grommet back on....then buy a bolt to plug the hole for the o2 sensor. it makes it a bit cleaner than just clipping the wire and leaving the old o2 sensor in there.


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## mcr_nismo (Jan 15, 2008)

and u guys have had no problems? wow. that shows how good of a car nissan makes....lemme xplain: o2 sensors feedback change the short/long-term fuel trim....without it the computer is not running off live-data and adjusting accordingly but off a look-up table.......this, essentially is jus a parameter in the computer with usable o2 readings already programmed that the computer uses. the problem is that without constant, changing readings u prob. won't get the best efficiency, but ur car will still run...just not the way it was designed....


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## Katana200sx (May 13, 2002)

mcr_nismo said:


> and u guys have had no problems? wow. that shows how good of a car nissan makes....lemme xplain: o2 sensors feedback change the short/long-term fuel trim....without it the computer is not running off live-data and adjusting accordingly but off a look-up table.......this, essentially is jus a parameter in the computer with usable o2 readings already programmed that the computer uses. the problem is that without constant, changing readings u prob. won't get the best efficiency, but ur car will still run...just not the way it was designed....


thanks for the explanation...but research how nissan, specifically the sentra, uses the rear o2 sensor. it is really only used in the emissions system. your car can run perfectly without the rear o2, and run like shit without the front.


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## mcr_nismo (Jan 15, 2008)

oh so they only use the front for reference? hm interesting. thanjs for that i didnt kno...well, im sure i couldnt remove it cuz of inspections in ny they'll prolly hav a fit!


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## azkicker0027 (May 31, 2002)

for emissions inspections, yes, you will have some issue, well, depending on the inspector or facility. i, myself have a free flow cat and i extended the sensor harness (sensor side) to accommodate the relocated cat. the ones that actually have the grommet on the under-body are mostly the 2.0L models.
i haven't had much trouble with my cat efficiency monitoring.


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