Hi guys,

I'm the happy owner of a 01 XJ since a year and so far I couldn’t be happier with my choice. I had to leave for 5 months so the jeep stayed in a parking all that time. When I came back, put the battery back in the car and it started right away. I drove a few miles then the engine stall. I was able to bring the Jeep back home by using some gas line antifreeze. The engine kept stalling afterward so I drained the gas tank and filed it up with some new gas. The engine run well but keeps stalling randomly (stops just like if I had turn the key). After it stalled I’m not able to start it again for 3 or 5 minutes. When the engine is running, it seems to run perfectly. I read that a broken crankshaft position sensor could cause the engine to stall. I would like to know what you guys think about my problem.
Thanks

 

If it's been sitting idle for a while it takes some time for the computer to "re-learn" the engine parameters, the problem may clear up on it's own. Any codes?

 

I dont get a check engine light or anything and I dont have the gear to check the codes by myself and at this point I'm still trying to fix it myself

 

I would like to know if changing the CPS is a really hard job or if its the kind of job you can do yoursel with some wrenching experience and basics tools

 

1. Be sure that your battery is up-to-snuff. Stalling is one of the most common causes of stalling. Any parts store will "load test" your battery for free. And yes, you can have a battery that is strong enough to start the engine, but yet weak enough that it gives the engine management system fits.

2. The crankshaft position sensor is a very common failure on the 4.0 When the input signal from that sensor isn't making it to the computer, you will not have spark and you will not have fuel going to the fuel injectors. They can be tested, but testing is not always conclusive. If you buy one, buy it directly from Jeep for the best reliability AND longevity. SEARCH this forum and the web for how to replace it.

 

You can take this for what it's worth. Read carefully.
I live in Macomb County, Michigan. I live near Chrysler Corp. world headquarters. Living on Chrysler's homeground, it isn't hard to meet retired Chrysler engineers socially. So here's my story...
I bought a 2001 XJ with 208,000 miles and a broken piston. I completely rebuilt the vehicle, doing all the work myself. All new parts mechanically except for the transmission, transfer case, differentials and steering gear. I'm retired, so I had plenty of time to work on it, and it took me a year, with thousands of dollars in parts. It ran like new until 222,000+ miles. Then it began stalling. No check engine light. I have an Actron code reader that I paid about $230.00 for at a parts store. It read no codes. Stalling was intermittant. I changed the CPS (Crankshaft Position Sensor) three times, but it continued to stall. Sometimes it would start, sometimes it wouldn't. Then I put on a reman PCM (Powertrain Control Module). The PCM was flashed to a vehicle with SKIM, unknown to me, so it would start and stall, start and stall...and yes, thew did ask me for my VIN and mileage.
Out of desperation, I had my Jeep towed to the dealer. They told me about the SKIM, and said I needed another reman PCM. Once a PCM is flashed to a SKIM vehicle, the process can't be reversed. I paid the dealer $817.00. Now the Jeep ran fine. I tool it on a trip the next day, to visit my son. Two hundred and fifty miles from home, it started stalling again. I had the Jeep towed to a dealer and rented a car to get home. The dealer called me the next day and told me I needed a new CPS (CPS #4) by now. I said OK. It cost me $270.00. A lot of money so far, but worth it if the Jeep runs dependably.
A day later. Jeep still stalling. Now I'm afraid to drive it. The dealer said it was getting an intermittant "loss of CPS signal". They said, at $98.00/hr it would be really expensive to fix. I gave up. Parked the Jeep at my son's house. Drove my Focus back home.
Back home, I began searching my circle of friends for a Chrysler engineer. It so happened I already had a friend who was a retired Chrysler Engineer, but we never talked shop, so I didnt' even know it! I explained to him my dilemma. Here's a summary of what he told me: The PCM reads malfunctions and stores them. Code readers can't see them. Only the dealer has the tool to see them. Intermittant malfunctions will be stored until the PCM decides to stop the vehicle. There is no check engine light, no nothing. The vehicle just stops running. The Actron code reader will show "No Codes". We discussed engineering a little. He told me that they has special meetings at Chrysler, where they made decisions on what things their dealers were told not to tell customers. Read that last sentence again. He said those "weatherproof" connectors are designed to be unplugged/plugged only a couple times before they begin to let moisture in anf fail! Just count the connectors on your car! Any one of them can corrode. If a critical pin corrodes, it can cause an intermittant, the car will stop, and you won't have a clue as to what it is! He said he WILL NOT buy a car. Any car. They used to be designed to last 100,000 miles, but now they're designing them to last 50,000 miles. The smartest thing to do is lease. Get rid of the car before it goes off warranty. Electrical systems are getting more complicated every year, making them harder to diagnose. Japanese cars are just as bad.
After our conversation, I had a thought. If you take a computer apart, you'll see many of the connector pins are gold plated. They say it's to prevent corrosion...

 

Hi all,
I found a new CPS on ebay for a good price so I decided to try replacing it. The new piece is now on the jeep since about a month and no stall since then. I’m not very familiar with the construction of theses sensors but on the top were the wire comes in there is a kind of clear glue that supposed to seal the hole piece. On the old one there is a hole in the center so guess that some water found a way trough and ruined it. Replacing it was interesting, the idea is pretty simple, removing tow bolts then replacing them but in practice it’s a bit more complicated than that. You need to find a good setup of ratchet extensions and u-joints to get to the bolts. I had someone helping getting the socket on the bolt from above. I will post a new reply if anything else happens with that but for now the jeep runs great so thanks for all the advice.