o2 sensor, necessary?
 

I just bought a 92 4x4 SB 4cyl 5 spd. There is no o2 sensor on the exhaust pipe, its like it was broke off in there. The guyI bought it from had just had a used 22RE put in the truck, not sure what year that engine is (if it matters). Truck seems to work fine without the sensor, but it is leaking exhaust from the hole. Should I do anything, if so what. Thanks, this is my first toyota.

Also what is the button on the dash to the left of the steering wheel (near the gauge dimmer) for? the cover to the button is gone and there is just a light on it.

Thanks,
Titus

Yes, you need it if it's EFI, when the O2 sensor goes bad, or isn't there the trucks usually run like crap and get TERRIBLE mileage and performance.

Ok, toyota wants about $200 to put one on. I can see where it bolts up to the exhaust pipe, but where does the other end plug to? Also do I need toyota part or just get one from Napa?
Thanks
Titus

i replaced the entire section of exhaust where the 02 sensor goes and the 02 sensor for like $150 with parts from autozone.

everything bolted right up after i cut all the rusty bolts off.

you will need to get some exhaust gaskets from the stealer though..they usually ahve them in stock.

Thanks,
Dealer just called back and said o2 sensor replacement would be $247 and then another $90 for diagnostics. I'll try and get one from auto parts store locally and put on my self. where does the other end of the o2 sensor go (there isn't one currently hooked up to see where to replace).
thanks for the help!

There should be a pair of wires with a plug on it up under the truck near the hole.

Give these guys a call about any factory parts you may need, they have the best prices I've seen:
https://www.1sttoyotaparts.com/partscat.html

My guess is it's the clutch start cancel switch. Push it and you will not need to push in the clutch to start the car. Of course, if it is in gear you'll start moving forward right away. Generally used off road for aggressive hill starts after a stall.. prevents rolling backwards.

In regards to the O2. The O2 has to "talk" to the ECM. Previous owner may have hacked things up a bit, but basically you will need to get the O2 sending a signal to the correct pins on the ECM. This may require a wiring diagram specific to your vehicle.

Hopefully... you'll find the original plug just tucked up in the frame rail somewhere. Would make your life a lot easier. :great:

Get the O2 sensor from sparkplugs.com for a fraction of the price. They sell a Denso O2 sensor, which is EXACTLY what Toyota uses, except they don't charge an arm and a leg for it.

Thats nice to know :)

Thanks for all the info, it sure helps. Just from looking I dont think my truck has a cataylictic (sp?) converter, will that make any difference on the oxygen sensor when I put it back on. Also the nuts and bolts are completely rusted together on the old o2 sensor, can/should I cut them? If I cut them will I have to have a new o2 sensor mount welded in? Thanks again for the help.
Titus

Not on a 92, they just had one O2 sensor before the cat.

On the rusted studs and nuts, try taking a wire brush (a dremel works good) and remove the rust on the studs before trying to remove the nuts. Also spray them good with PB Blaster and let soak for a while. Only cut them off as a last resort because no one sells those O2 sensor bungs. The dealer will sell the whole exhaust pipe as a unit, but not just the bung and muffler shops don't have them either.

If you have to cut the studs off the best bet would be to drill out the old studs and use an easy out or helicoil kit.

Another option is to make a bung from scratch:
Getting ready to have a custom exhaust system built from the cross-over back. I couldn't find anyone that sells a Toyota O2 sensor bung to weld into the new exhaust piping. After talking to a friend that works at the local Toyota dealer about where to get one, he says why don't you just make one? I hadn't thought of that Jason, thanks for the idea. So here's how to make your own O2 sensor bung.
I started with a piece of 3/8 steel and marked the outline with a gasket and drilled and tapped some holes (8mm x 1.25):
http://thumb7.webshots.net/t/53/453/...7vaOsbl_th.jpg

I used some exhaust studs from the dealer that were left over when I was putting on the ORS cross-over.

http://thumb7.webshots.net/t/26/26/0...7dWRHaL_th.jpg
Then I started cutting it out with a cutoff wheel on an angle grinder:
http://thumb7.webshots.net/t/32/33/2...7tRaKPw_th.jpg
After using a grinder and beltsander to smooth it out:
http://thumb7.webshots.net/t/14/14/2...7GwsXWe_th.jpg

Now that was one bung, but I need two for the 5VZ right. The first one took me about 2-3 hours to make so I decided to try cutting an old one out of my old 3.0 exhaust pipe and using it. That took about 2-3 hours too, counting replacing the old studs and smoothing it out with a grinder and beltsander too.

Here's the two side by side, the one I made from scratch will have to be welded in parallel to the pipe since it's not curved to the shape of the pipe:
http://thumb7.webshots.net/t/57/657/...7rmpaHb_th.jpg

http://thumb7.webshots.net/t/59/759/...7usqSGv_th.jpg

or if you dont wanna run a cat - www.o2simulator.com
i have no expierience with them but they are prtogrammable

Its not that I dont want to run a cat. I just bought the truck and there isn't a cat or an o2 sensor. The exhaust is leaking from the o2 bung and another hole a few feet down next to a hanger weld. I'm short on cash right now, but I guess I need to get a whole new exhaust pipe with a cat and a new 02 bung. Thanks again for the help.

Get some of the muffler wrap/repair stuff and seal the holes and worry about it later :) .