Burgy

I searched for info on this but nothing came up

I have a 2001 XJ, and just picked up front manifold and rear manifold o2 sensors at parts store. When I went to put them in I found that I have 2 sensors on the manifold and one further down the pipe before the cat. On my 98 TJ I only had two sensors, so I was a little surprised to find three, and now I'm confused as to where the two I bought should go. The parts store only listed one other sensor for after the cat, however I looked there and couldn't find one. My instinct is that the front and rear manifold sensors go in that order on the exaust manifold and that the o2 sensor listed as after the cat actually goes in the pipe before it. Anybody else out there have this set up and replaced these?

djb383

Look again, I'll bet there's an O2 at the tail-end of the cat, maybe toward the middle of the vehicle.

Burgy

So are there 4 o2 sensors on the late models?

19558077

my 00' has four, 2 updraft and 2 down draft. right at the manifold are two small converters each with 2 sensors. thats why i havent replaced any yet.

JJaycXj

yes i believe you have 2 before the cat and 2 after.

JJaycXj

yeah same here i have that to. the 2001 have the 4 as well

djb383

There's two O2's after the main cat?

19558077

mine also has the main cat. just before the muffler, but no sensor.

Burgy

Ok, I was wondering if those were two mini converters. djb83's pic of the cat looks exactly like the one on my 98 TJ, but the main cat on my 01 XJ is much smaller. This is starting to make more since, but I still can't figure out which o2 sensor goes where.

19558077

havent looked at mine too close yet, but with the two small ones next to the manifold i couldnt take the oil pan off cause the converters/pipe was in the way of the pan bolts. mine are 2 small round conver. basicly made into the down pipe on the manifold.

Soldat

I swear I only saw two on my 2000, and I planned to replace them soon.

Now I am scared I didn't look hard enough and will have to replace more.

Burgy

Mine looks exactly the same. I'm gonna try to take some pics tomorrow and post them.

Here's what I have for Bosch part numbers and descriptions thus far.

Before Cat
13100 O.E. type Exact fit; located in front manifold/exhaust pipe.
13122 O.E. type Exact fit: located in rear manifold/exhaust pipe.

After Cat
13138 O.E. type Exact fit: located in rear manifold/exhaust pipe.


What I'm thinking is that the 13100 goes in the two small canisters/converters, the 13122 is downstream in between those two and the main cat, and the 13138 goes after the main cat. I'm just going to pull them all and see, might try to cross reference part numbers if I can get any off of the old ones and let you guys know what I find.

Burgy

Ok got back under the Jeep this morning and this is what I found. My 01 only has three o2 sensors one above each small converter and one after them before the main cat. There are no sensors in the main cat or after.

I'm not sure what year they changed this from the previous style with one sensor after the manifold in the pipe (around the oil pan) and another in the cat.

If you have a California emissions model, then you will have four. Two before the small canisters, and two immediately afterward.

Here is a good link with pics for California models http://www.4x4xplor.com/O2-sensor.html

Its 16 degrees out this morning so I wont be changing these today, when I do I'll take pics, might turn this into a write up since there doesn't seem to be one on here yet.

ReverendOD

We get a answer on which sensors for the 2 pre cat? Im getting conflicting info.

Rockauto says Bosch 13100 (front) and 13122 (rear)
4x4xplor says Bosch 13122 and 13280
Advance Auto says 13100 for both front and rear pre-cat

So which is it or is the only difference the cable legnth?