frisbeedog

I have ordered and received a new O2 sensor. When i crawl under the 4runner I can't decide the easiest way to replace the sensor. Do I need to remove the rocker panel cover and a portion of the carpet to get to the electrical plug? All I can see from down below is the rubber gasket through the floor board. The bolts are going to be a serious pain in the wazoo!

Your help is greatly appreciated and will be rewarded with pics!

bugs1961

The O2 sensor on my 3.0 truck is screwed in the exhaust pipe under the vehicle and is easily accessible from underneath. The sensor is just upstream of the cat. Post a pick of the part you're replacing to get a better idea of what you're talking about.

frisbeedog

I know where the O2 sensor is bolted into the exhaust pipe. What I'm wondering is how to get to the other end of the wire. There is a rubber gasket mounted to the bottom of the floor board and somewhere there is a white plug to connect.

Team420

How many miles on your rig? Maybe a p.o. changed it, and just hard wired it.... thats what I did, why spend an extra $40-$50 for a plug, when u can hard wire in 10 min?

frisbeedog

That is entirely possible! They may have done that the same time they cut out the cat!

However, I still think there is a need to remove the rubber grommet from the bottom of the floor board to get to the plug. The new O2 sensor has a new rubber piece and the plug.

Jay351

You shouldnt have to remove anything to get at the plug.

The original o2 sensor plugs into the exhaust, then about 15" or so down the wires it clips onto the truck harness. All external...

I got my direct fit NTK o2 sensor for under $50 from sparkplugs.com...

Kiroshu

There should have been a connector there to just unplug and plug in.... if not then someone decided to hide it or its hardwired like everyone is saying.... just take it back and get the one with no connector or cut it off the one you got now... ur choice....

Jason4X4

my buddies 89 3.0 had the plug under the drivers seat, either remove it or slide it forward.

sb5walker

However you wire it, be sure it has an EXCELLENT electrical connection and is protected from corrosion (and kept off the hot exhaust).

O2 sensor signals are .45 volt for perfect mixture, higher for rich mixture (up to 1 volt), and lower to .1 volt for lean signal. Those are tiny voltages and even a very small amount of corrosion or bad connection will reduce the voltage of the signal enough to be a problem. For example, if the mixture were too rich, and the sensor, working properly, sent out, say, a .6 volt signal, if the signal were degraded even .3 volt, which is not that much, the computer would receive .3 volt and conclude that the engine was running too lean and add more fuel.

So if you hard wire, don't just twist the wires together and tape. Clean the wire ends shiny and grease free, and solder them. Then spray with a dielectric wax sealant like boeshield t-9, and then tape, or use heat shrink tubing. You could also use dielectric grease if you can manage to tape around it or use shrink tubing.

frisbeedog

I finally got the little booger installed. The 02 sensor from sparkplugs.com did not fit. The NGK website listed #24112 which i received from sparkplugs. I ended up redrilling the holes to match the bolts on the bung. The electrical plug is located under the drivers seat in the interior and is easy to get to since the carpet just pulls up. I was hoping for a little better fuel economy, but no luck there so obviously i still have some tuning up to do. Thanks for your input guys!