1998 Gen 2.5 - O2 Sensor replacement - Mission Impossible?

[nwoods]

I'm told there are four O2 sensors on the 1998 Gen 2.5 with the 3.5: SOHC engine. I can only find two, one just ahead of the cat, just after the right and left bank exhaust manifolds merge into one pipe before passing through the Catalytic converter, and another between the Cat and the muffler.

My Montero is throwing a P0141 code, which is O2 sensor, Bank 1, Sensor 2, so it should be the aft sensor.

I was able (after a lot of PB Blaster and minus a few inches of skin) to get the sensor off for replacement, but I was completely unable to remove the harness clip it plugs into. I simply can't get my hands up into the tiny space above the transfer case where both O2 sensors have their plug in connectors located.

Has anyone done this maintenance item? If so, how on earth did you access the harness clip to release the connector? I was thinking about going to the local park and luring some kids with skinny arms under my truck with candy or something......LOL. Seriously, I the only thing that seemed a viable possibility was to unbolt the cross member, and drop the transfer case to get at these darn things. Anyone have a better suggestion?

Here is a photo of the harness, and for scale, a long skinny flat tipped screw driver that is about 10,000th the diameter of my hand.

 

[TheMole]

It does look tight in there. Is it accessible under the armrest console? Last option would be to leave the plug, but cut the wire and re-solder on to the new sensor.

 

[Pdivizzle0112]

Try using a set of long picks with 90 degree bends on the end. One to disengage the claw, one to pull the connector. That's how I did it when I was working on lexus cars. My hands are pretty huge. If you still can't get it off you can always put a jack under the trans and remove the mount and lower it down an inch or two to gain some more clearance

 

[plh]

I did them on my Gen 3 and those 2 harnesses are essentially in the same position. Real bugger to get to. Maybe my hands are smaller, took a lot of persistence and a pick tool. Definitely the longest part of the R&R.

 

[jeep-N-montero]

It has been almost 2 years since I replaced all of the o2 sensors on my 98, I can't recall how I got the clip off but I did spray out that area with brake cleaner to push some of the dirt out that collects under the clip and makes it hard to push in to release.

 

[montero98ls]

I remember that one being a pain can't give any advi e but just thought I'd let you know you're not alone lol.

 

[nwoods]

LOL. I took it to a shop. They put it on a lift, had a skinny guy unclip it and plug in the new one. They screwed in the new sensor unit and cleared the codes and I gladly, though somewhat sheepishly, paid them $60 for their time and tools.

 

[rahee006]

Mine is stuck so bad, that using a torch didnt help. it still didnt come out. i have 4 assuming mine is a california spec montero