I am having a new exhaust put in my 3.4L swap (96 3.4L M/T 4x4) and the exhaust shop said that the after cat O2 sensor needs to be exactly on per the manufacturers spec. They have the truck right now and need this information this morning first thing!

Where does the rear most cat need be located?? (So many inches, mm, etc after the cat baffeling).

Also can I use regular style round hole O2 sensor bungs in place of the stock Toyota style studded mount? Does Denso sell this style o2 sensor for the Toyota??

Thanks,

 

I'm not sure on the distances for you, but they are correct, it needs to be pretty close to stock location for the cat to function properly (like goldilocks and the 3 bears, not too hot, not too cold ). I'll let another 3rd gen chime in for that part since I don't have mine handy now.

You should use the stud style and not the threaded bung for mounting your O2 or you may not be able to the correct sensor to fit your vehicle. If it were my truck I'd do the studed type even if it was a bit more work.

 

ok new question.

For the studded style O2 sensor bungs. I have one that I got with the engine which is located before the cat and another from my original 94 exhaust system. Can I use these two existing bungs in my new system? Because I have read this morning somewhere that the physical sizes are different for the before and after cat o2 sensors and might not fit. Can anyone confirm this?

 

On a 96 the front and rear sensors should be more or less physically identical (even though they have different P/N's.....I think the difference is the tail length but Gadget would be the best to ask on that). On the 94 I have no idea if they are the same size or not as the 96-98 3rd gens. If you have the two handy you can just do a side-by-side comparison of each and see how well they match up. As long as the sensor is in the exhaust stream, it is the correct distance from other components (front sensor - cyl head, rear sensor - cat, etc) and it can seal properly, you shouldn't have any issues.

 

bumped