OK, I joined the forum to say thanks to Bond-Jamesbond for his method above (and because I have a bone-stock '97 XJ that I am going to lift, but that's a subject for another post).

I used the method above to replace the CPS on my wife's 2004 Grand Cherokee, and I can tell you that it works. It was still a lot of work, and still a pain in the a##, but it was probably a lot easier than dealing with the transmission/cross member.

In the process of making this repair, I came across a few things that I think might be helpful to others.

Honestly, this was still a fairly difficult job, since working through that small opening was rather tedious. If I had access to a lift, and had to do it again, I might go with the "book" method by dropping the crossmember. But I don't have a lift, so that's a moot point.

First and foremost, there is a recall on 2004 WJs covering the CPS. Officially, the recall covers "frayed wiring" at the CPS and not the sensor itself, but if your dealer is cooperative, you might get the job done for nothing. Unfortunately, that didn't work for me.

To elaborate a little more on jamesbond's method, there are actually two cables that run through the firewall in the area he describes. The plate you want is the "top" one. It's the further back and higher of the two. Once you remove it, the CPS is indeed right in front of you. However, it's about 6" inside the firewall, and just off center with the opening, so you'll need an long enough extension and a swivel socket or u-joint.

My u-joint was too "floppy", so I wrapped electrical tape around it to stiffen it up. That made it stiff enough for both removing and installing the single bolt that holds the CPS in.

Once you get the bolt out, the CPS pulls out of its mounting hole. You will need to rotate it about 90 degrees to get it out the last little bit. That was worth at least 30 minutes of frustration before I figured it out! I used a radiator hose type pick to reach through the hole and rotate the sensor.

You will need to unplug the sensor under the hood. On my '04, the plug was between the valve cover and the firewall. It was easiest to reach from the passenger side.

When I disconnected the old sensor, I tied a long string to the wire and pulled it into the cab through the same hole described above. Then I connected the string to the new sensor wire, and used it to fish the wire back to the connector under the hood. The wire is routed between the engine and firewall, and there isn't much room to work back there.

Here's a pic that shows the string. It also shows both cable plates.



I ended up modifying the air duct mounting tab as jamesbond described. Made it a lot easier to re-install.

Here is the "after" pic of the duct.



I have some photos that I will try to upload later.

Thanks again, Mr. Bond!

 

I too joined to say thank you to you guys for the tremendous help in replacing my CPS on my 02 JGC. Without this forum I would have been out a lot more money. I'm a computer IT guy and would sadly rank myself as a 2 on the 10 point mechanic scale but thanks to you guys and these forums I was able to tackle this monster. My tool selection has grown as well

CPS replaced (with a ton of nicks and bruises on my hands, but well worth it) and now the blue beast runs like a champ!

Thanks again!

 

First of all I also joined this forum to say thanks. After several trips under and over the jeep I could reach the CPS. Then I found this.

This thread was a real help.
couple things I learned in doing this.
First, us a 1/4 socket, and a 2 inch extention with a phillips bit in it on a 1/4 drive ratchet to get the screw for the vent lose.

clamp a light under the hood on the drivers side shining at the cps.

Dont bother trying a 3/8 drive with a swivel. Use a 1/4 drive with the swivel attached right to the the 11mm socket. Use the string method.

After you get the bolt loose. use a pair of needle nose to pull it out. Helps to keep from chasing it.

when you get frustrated walk away and come back later.

 

Just to let you know how I did it.

I have a UK 1997 so no inside panel to remove.
I found if you remove the air filter and get a friend (sucker) to lay underneath with about 4 extension bars on a 11mm socket you can wiggle your hand in from the top and hold the socket on.
That way you have no chance of dropping the bolts inside the bell housing.
After struggling for hours on my own, it was a 15 minute job with two.

Nick

 

I got at it form underneath. Just had to unbolt the U-joint strap and drop the driveshaft, then it was relatively easy.

 

I have been doing some research in preparation for replacing the Crank Position Sensor on my XJ. I have never done this before but the write-ups on this, and other forums, will be very helpful.

The one thing that I have not seen covered in any detail is this - how do you actually START the two bolts during the reassembly process. Is there enough room to reach in with your hand and thread them into their holes, or do you have to start them with some of the socket extension/u-joint combinations I’ve seen illustrated. If so, it would seem that it would be a bear to get the bolts up to the holes without the bolts falling out of the socket. The chances of cross treading the bolts is also possible.

How do you guys do this??

 

Well I replaced mine for the second time and its really easy to do
I just hand threaded them and bolted them down

 

Some people really need to buy a haynes manuel some peoples questions are common sense

 

Hey guys, it's me again, Bond-JamesBond.... Anyway, how cool to see so many people saving $$ by doing this CPS change themselves quickly and easily!!
Anyway, I sure appreciate "MIKE 662" for posting those photos - spot on! And the rest of you guys who have fine tuned the process! I have had to change my CPS twice now in a year. The 1st was Chrysler NOS CPS which cost something like $135 and failed in 3 months! Then, I said "F" it, I'll put in a cheap Autozone Duralast CPS for $34 that has been trouble free ever since.
In regards to putting the mounting bolt back in at that slight offset through the firewall access panel, I had lost my original bolt so I just took the same size bolt and ground the tip into a bit of a cone shape to make a "drift" type self centering bolt and it slipped right in and caught the threads perfectly.
You know, a black JGC won't necessarily get you home but it sure does get the girls...!

 

The older models are an 11mm socket

 

Thanks everyone for the post ups. Did mine last night. Can't believe how many problems it fixed.

 

When I did a buddy's CPS to start the bolts I set the bolts in the socket. Used electrical tape to tape the bolt in the socket and used the socket and extensions to start the bolt. After you had tighten it the tape breaks and comes off with the socket.

 

I've done probably 20 of them. It's a 10 or 15 minute job.
You need a helper on top to guide the socket on from above, you underneath with a long extension with a u-joint on the socket end.
The helper grabs the bolt as it comes out.
Going back in - a small piece of tape or socket magnet to hold the bolts in the socket.
Helper holds the new CPS in place and guides your bolt/socket on from above.

No dropping anything, no cutting or modifying anything. A good flashlight helps too.

Some have only one bolt, some 2.
If you want the new one to last - get it from the dealer - AutoChina's knock-off's are only good for a few months - if that long!
Price is nearly the same.

 

I've done it without a helper all from underneath many times

 

Easy 10-15 minute job.

You underneath with ratchet, extension, u-joint, then socket. Wrap tape around the u joint to make it stop flopping.

A friend on top guides it on the bolts and retrieves them as they come out.

Same going in - tape the bolt in the socket so it stays there, friend on top guides it on.

Problem is when you have the socket close you can't see it - but the friend can!

Works for all years, XJ, GC and Wranglers.