Which sensor is going out??

[8Mud]

I used to always check mine for pulse, never knew there was an ohm test till recently. If you don´t get a pulse reading on low voltage D/C, try changing to the A/C scale on your meter.
It´s worth it to test the CPS wires at the plug to ECU wires at the plug, with an ohm meter, this will tell you if you have excessive resitance in the C 101 plug.
I jumped the C-1 (purpel with white stripe) and D-1 (white with black stripe) pins at the C/D (same plug) connector at the ECU, with a small piece of solid copper wire and measured resistance in a loop at the CPS connector. Will tell you if there is much/any resistance in the wiring.
I may have the colors for the C-1 and D-1 pins reversed, but it doesn´t really make any difference.
I didn´t find any resistance for the CPS on mine at the C-101 plug, but did find resistance for the TPS, I just jumped the TPS wires at the C-101 plug and left the rest as is, the rest tested OK and had "0" resistance ("If it ain´t broke don´t fix it").

 

[jephs422]

welll I checked the ohms, and everything looks fine with the cps sensor. At this point my other ride starts school on Monday. So off to the mechanic it goes. I'll let you guys know what it was after I find out.

 

[Dragon_Fly]

I had some similar problems with my XJ. I tested the Crank Positioning Sensor, TPS, MAP, IAC, etc... all tested good. I did search this site and a few others for some answers. There was a thread on cleaning the main wiring connection located above the power brake booster. Spent about 20 minutes cleaning it with a small wire brush and some electronics cleaner. Then applied a fresh coat of dielectric grease. That seemed to work for my issues. I wanted to see if maybe it might work for you so I thought I'd at least mention it.

I looked for the camshaft positioning sensor on my 1988 4.0. Nothing is listed in the parts manual for that year. I also looked at the schematic of the distributor for my XJ. Where is it located? Any photo's? schematics?

 

[87_jpchrk]

rty changing your crank position sensor first. Get the recall kit from Crysler. You will need to change out the cps harness with this install! the lit Runs about 40 bucks if I remeber right! The high idle can be from a throttle position sensor going south or out of adjustment. You will need to get a meter out and check the resistance of the sensor. if for anyreason the meter goes OL while you open the throttle or if the voltages arent where they are supposed to be it needs to be replaced. You will have to get the correct parameters and the wiring locations from a factory manual.

Brian

1987 XJ 7" lift on 33's
2002 KJ Liberty limited stock L.O.S.T. member #00711

 

[jephs422]

Okay, so the Jeep dealer called me today, and this is what they told me.

First let me tell you that my Jeep miraculously started so I was able to drive it there instead of towing it. So when they tested it they said everything looked fine. Just my luck. But then he said they tested all of the sensors and they looked fine. He said that Crank sensor was reading a lot of resistance. Well when I read it, it was reading .199 ohms. what the heck. ANyhow, I told them there is now way in heck I was going to have them change it to the tune of $220.00. I said dude, it's two bolts and a $35.00 part. Man I hope that is it.

 

[jephs422]

Well, I changed the Crank sensor......And of course, it still won't run. I fiddled with it for a few hours last night, and it started(miraculously) long enough to drive around the block and park it in front of my garage. I have a feeling it has to do with the module my coil drops into. any thoughts?

 

[jephs422]

well, I changed my ignition mogule, and now it runs great. go figure

 

[Gil BullyKatz]

Good deal...
Now all ya gotta do is wait for the next problem to surface...
You kept that old CPS as a spare right?

 

[jephs422]

hehhe...yeah I kept it. But not before remembering it was fine and digging it out of the trash before it got picked up!! At least I now have 1 spare CPS and one spare Coil!!