dannomite

Hey there. I will start off as many people do by saying that I have searched, both here on YT and over the interweb. I am looking for a wiring diagram for an o2 sensor bypass resistor. The reason I am doing this is that the sensor mout rusted away and my buddy kindly welded it up for me so that I did not have an exhaust leak. Then another buddy gave me the bypass resistor. With no instructions. My rig is a 96 4runner with the 3.4. I am good with wiring. I just need some info on what goes where. I suppose that I should add that I do not live within 900 miles of anywhere that has to have emissions checked. If I have left out any pertinent info please just let me know. Also if I somehow turned stupid while I searched please be gracious I have been on YT for a while and have never posted an "I need help" thread before. Thanks in advance.

mt_goat

Do you have 2 O2 sensors on that year truck? If so, are you talking about the rear sensor (I hope)?

dannomite

There is one sensor ahead of the cat and one behind. I am talking about the one behind.

mt_goat

Ok URD sells this one: http://www.urdusa.com/index.php?cPat...0r1dulriefvd73 It works good for me. If you are really wanting to make your own I have posted those instructions before on here. I'll see if I can find them again.

dannomite

I don't want to make my own. My buddy bought one for his taco then decided not to use it so he gave it to me. mine is just the resistor block with 4 wires coming out of it. I just need to know what goes where.

mt_goat

Does it look like the URD unit or who made it?

mt_goat

New bungs can also be made and welded in if you can't find wiring instructions for your sim.

dannomite

I think I will harass my buddy some more for the instructions. The reason for not getting a new bung is that The simulator is free and the bung is not. Although, if I can not figure out how to wire it in then I will get the new bung. Thanks for the input Mt. Goat. Oh, and no it does not look like the one from URD, I will try to remember to get a picture of it later and post it up.

mt_goat

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):



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



Then I started cutting it out with a cutoff wheel on an angle grinder:



After using a grinder and beltsander to smooth it out:



Now that was one bung, but I need two for the 5VZ. 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:

mt_goat

Oh I almost forgot something very important. Some sims, like the URD unit require a working rear O2 sensor in place for them to work.

dannomite

Good to know. Thanks for all the info.