cps ??'s...stalling, long starts

[scase86]

ok guys. Ive been searching the forum and putting off asking this for a while. I always figured I could find some information that would pertain exactly to my situation but it hasnt happened, now I cant drive my cherokee. anyway here is the problem... Here recently my truck has been suffering from an issue of random stalling, and long starts. It stalled for the first time the other day on a normal daily drive. at first I figured it was a simple one time glitch but ever since that one day it had stalled every time I drove it, usually multiple times in one day. So, I parked the truck figuring it to be a fuel pump issue but pressure was steady at 32 pounds w/ vac, 39 w/o. Ironically while I was testing pressure I accidently touched an electronic connector near the rear of the engine and just like that the engine died. It didnt stumble or miss It just died. Figuring it was a fluke I tried it again and again and everytime I messed with that connector the truck stalled. I have a haynes manual, and while not very helpful I did find out that the connector was comming from the CPS. I do know that when I touch the connector, it slightly moves the sensor on the bellhousing. I am wondering if my sensor is shot? I read somewhere on the board that a good sensor will put out about 125-175 ohms...mine is hovering right around 265-280ohms at idle. Now aside from that ohm measurement here are the symptoms my truck has. If anyone can tell me if they are indicators of a bad CPS please let me know...

1. long starts, usually 5 seconds or more.
2. quick stalling, no stumble or miss, just a sudden stop...like there is no spark
3. I notice that the engine dies when its up to operating temperature only.

if I do come to find out that it is a CPS malfunction how hard is it to replace? I am a fairly big guy so getting my hands to it looks like it will be a pain. thanks for the help.

 

[jimmyc75]

ok i am sort of having the same problem and i have a chiltons book it sucks.

 

[XJGraham]

I recently did mine on my 95. Probably one of the most awkward sensors to get at but it can be done. Mine was a auto if you have a manual I am not to sure how hard it is to get at but I know the parts cheaper. I recomend about 2' of extensions and a lot of patients. A little tip trying using a piece of gum to hold the bolt in place while you try to screw it back in. Another option is lowering the transmission to give you a little more room up there. But if you said that the sensor is moving when you touch it make sure that the bolts are tight holding it in.

 

[scase86]

yeah mine is an 87 automatic. I havent actually been able to get a good look at the sensor yet...I am assuming that it is just a single bolt holding it in place?

 

[XJGraham]

Its 2 10mm if I remember correctly but definetly 2 bolts.

 

[scase86]

actually my sensor isnt moving at all as I though. instead its just the wire going into that is moving...so I am clear there. however the more I read the more I see that there are problems with the connectors that these trucks use for the CPS. Does anyone know where I can find this "upgraded" connector?

 

[87manche]

Have you cleaned the connecto with contact cleaner and made sure none of the pins are bent or coming out of it? I had major issues with my CPS connector, I just cut the connector out and hard wired it together. Problems solved. If I ever need to replace the CPS I'll just solder that one in too. Also, make sure that the wireing harness for that sensor isn't melted against the manifold or downtube. Mine had the wire loom a bit melted, so I made sure to tie it back from the downtube with some wire ties