Has anybody done this? I know it will be a pig to move once I get to it, but I can't even see it. I know its around the area of where the manifold meets the downpipe, but looks like there's too much stuff in the way. So, does anything need to come off to get to it? Any clues, tips or pic would be awesome!
thanks

 

It's easy if you lay under the Jeep on driver side or left side, it's right there beside the oil pan on the down pipe unplug it first before you break it loose, it also takes a 7/8 wrench

 

I remember removing the air filter box to get at it from above. I also did some things from below, but 3 years ago and don't remember all the details.

Press on . . .

 

Isn't that the downstream sensor - I took a look underneath and that one seemed relatively accessible..

According to a diagram I saw the upstream sensor is on the manifold just about where the downpipe (and cat) is bolted to the manifold.

 

On my 99 neither are that hard to get to.. Took a little bit of umph but thats about it. The upstream is about 6 inches below the headers on the side of the oil pan. There is nothing in the way. The downstream is down after the cat about 10 inches past the transfer case.

 

The downstream is after the cat. The upstream is in the downpipe, should be pretty easy to get to. I didn't have anything in the way when I did mine

 

Nope its the upstream, the downstream is after the cat past tcase on right side

 

Great - thanks guys!

 

Well I guess its different on later models. My 2000 has the downstream sensor in the postion in the picture above - but I have a bulge in the exhaust downpipe which I assume must be the cat, unlike the pic above which has no bulge. I checked all the way to the back after this one and there are no other sensors. The upstream sensor as it turns out is on the underside on the manifold (header - sorry I'm a Brit) at the back, and a b***h to get to. I did them both, and checked the numbers on the original parts I pulled off to confirm which was upstream and downstream.

 

i replaced 1 between & cat manifold

is there only 1 in '93 ?

and .. are all pipes squished like that pic ? mine is .. thought it was odd looking

 

Yeah only one on 96 and older that pic is of my 94xj my 2000 is in the same spot and it has one behind the cat.

 

97-99: Upstream sensor in downpipe above front drive shaft, easily accessible from underneath. Downstream behind the cat beside transfer case.

2000-2001: Upstream sensors in exhaust collectors, one for cyls 1-3 and one for cyls 4-6. Downstream sensors after the "pre-cats" in the collectors, installed before the downpipe. Might be able to get at them from underneath. The upstream ones you should remove the air box to get to, but if you're bored you could take off the whole intake manifold and clean it thoroughly, which would give you some space to work.

nickxj94: You sure yours isn't a 1999??? Does it have coil packs?

 

Salad - mine is def a 2000-2001, but only shows one upstream sensor on the exhaust manifold (collector?) underneath, toward the back. I thought there were only two on the California models which had a split manifold and two downpipes with pre-cats? (and also two downstream sensors). I have one downpipe/pre-cat.

 

One downpipe/pre-cat? How do you know it's a 2000? Does it have coil packs and a low-pinion Dana 30?

 

Yes it does! I am 100% sure says it on the door and title lol! My 94 is actually a 95 well 11-94 build date