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2G Getting That Rear O2 Sensor Through The Floor | Wideband Gauge


Proven Member
Jul 1, 2021
Nashville, Tennessee
Installing a new wideband to replace an old AEM UEGO (35-8460) in the rear O2 location with a new FuelTech Wideband O2 Nano.

Car’s got a cat-less downpipe, so the spot is almost directly under the driver’s seat. Naturally, I’ve opted to go the route of taking out the driver’s seat to do the replacement.

I’ve been browsing around to see if anyone has posted any images or video of how they managed to get the connector through the hole from the underside, and have come up short. I’ve already removed the driver’s seat, but on this last attempt couldn’t quite figure how to go about it. The hole looks too small for that connector to come up and through. Anyone have advice? Or maybe pictures?

Maybe this new thread could help someone else with it in the future?

And obviously me right now 😂



15+ Year Contributor
Aug 27, 2006
Regina, SK_Canada
De-pin the connector and reinstall. Or could cut and solder? Not sure if that would effect the accuracy of the sensor, I would doubt it but maybe someone else can chime in.

Justin DuBois

Proven Member
Aug 15, 2019
Oakland, California


Proven Member
Sep 20, 2022
Shippensburg, Pennsylvania
Just a thought. I run my WB02 in the turbo elbow. Added a second bung under in the downpipe for the original upstream o2. You could also just simulate using ecmlink if you didn’t wanna add a bung. I also locked the rear o2 voltage and used its original ecu pin for the data logging. I know a lot of people run it in the rear o2 bung like you are trying but I think it’s maybe a tad better in the front minus the extra heat. I know this doesn’t answer your exact question but just telling you my experience and how I’ve done it which solves your problem LOL good luck.


Proven Member
May 27, 2017
Odenton, Maryland
I cut mine and resoldered. Won't affect the readings if soldered correctly:

Strip Wires. Put heat shrink on wires. Detwist and fan the ends a little less than 1/4 inch. Mesh the ends tigether so the wires are fully interlaced. Twist wires together so they are locked (tightly wound and not easily pulled apart). Solder smoothly so solder is completely spread through wires and you can still see the strands. Heat shrink. Electrial tape together.


10+ Year Contributor
Dec 17, 2009
Pensacola, Florida
Honestly I tried to fit it through the hole but was too big for it(giggity) and just ran it the extra foot or two to the firewall and ran it through the grommet that the column passes through. It already had a hole in it so I just poked it through more and sealed it back with RTV. Worked great and it put it right where I needed.

But honestly I don’t see why you couldn’t just use some tin-snips and just snip it in a couple spots and bend the hole wider. After you’re done you can re-coat it with paint or etc to stop rust.


Proven Member
Jul 1, 2021
Nashville, Tennessee
Thanks folks,

While I was at it, I realized that I forgot to mention I was trying to reach a bung further upstream, and I was thinking I had to go through the rear O2 opening.

As it turns out, I found it was routed to a hole a few inches forward of the drivers seat. So I ended up opting for the method recommended by @Vegas Smith, using a step drill to widen it just enough to fit the connector through. I secured the wire under the frame with a screw behind a big washer.

Topside, I wrapped the excess wiring and tucked it away. I cut rubber grommets and fit them around the wires at the opening in the floor on both sides to insulate the hole (as it wasn’t insulated before).

Checked the wiring I’d already done (drawing power from the cigarette lighter), and everything worked perfectly when I finally got to turn the key.

Appreciate it, everyone!

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Proven Member
May 27, 2017
Odenton, Maryland
Excellent! Glad you got it working. Did you paint the floor pan where you widened the hole to prevent rust? If not, you can go back and use some clear fingernail polish (or the color of your choice) to do that. Hit it with a little sandpaper first to resolve the flash rust that is already on there. Easy to do.


Probationary Member
Mar 7, 2023
olathe, Kansas
just curious if you had the settings for the old gauge you had hooked up ? i have mine wired in to be able to datalog but there is no selection for this guage.
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