2001 Cherokee. 140k miles. Driving home from dinner a week ago, Jeep suddenly dies at stop sign. Restarts and we continue home. Drives another 3 miles and dies again. This time, wont restart. Cranks, and cranks no start. Insurance policy has tow so we call and wait, and wait, and wait. First tow doesnt show so we call back to insurance and second tow truck comes about 30 minuites later. All in all, a good 2 1/2 hour wait. Tow truck operator tries to start it. Starts up immediately, runs about 3 or 4 seconds and dies. He hooks it up and tows it to my house about a mile away. I tried to start it again, starts right up, runs 3 or 4 seconds and dies. After a day, it wont even do that anymore, just cranks, and cranks but wont start.

I am mechanically inclined enough to change oil, plugs, basic types of things. I know a mobile mechanic that I have used previously for other vehicles so I call. Unfortunately he is no longer doing mobile and his shop is just way too far to tow it again. So, I scan the YP for another mobile mechanic. I dont really want to get into specifics of what I think of this guy's abilities etc. It's not really relevant to my question but lets just say any monkey can change enough parts until they get the right one. He thinks ignition cylinder could be bad, call a lock smith get a new one and reprogram keys. Didnt work. Thinks it could be the fuel pump, changed the fuel pump assembly, didnt work. He scratches his head and determines it's beyond his ability to fix it, thinks it could be the PCM. So, basically I know it is getting spark, he did know enough to determine that. I know it is getting fuel pressure. Where to start looking now? I have read several things about the 4.0 liter motor and the crank position sensor. I dont ever recall seeing the voltage indicator acting funny, it has never exhibited signs of dying like this before or having any type of no start activities. One thing that has gone on for a while is the gas guage and distance to empty readout has acted funny-from reading as if empty to bouncing all around between actual volume of gas in tank and empty. There have been a couple of check engine codes present. I cant remember the numbers but one was random cylinder missfire and the other was the switch in the leak detection pump acting slow or sticking.

I'm sure I left out all sorts of necessary details so if you need more, just ask and I will try and provide.

 

You can try the search feature that we have on the site to find out how other people worked through their no start problems. I will give my 2 cents and just say it might be the auto shut down relay in the PDC fuse box on the passenger side of the engine compartment. switch with one similar to it and see what happens, also check the fuel pump relay, and for the heck of it the battery and cables.

 

Recently had problem w/ no start next morning after it was running fine (2001 Jeep Cherokee Sport Limited-165000miles). Tried recommendations on this site 1.Battery-was good 2. removed Starter and had it tested-was good 3. switched out ASD relay w/ similar relay(located in fuse box under hood)-was not the problem. 4. Read about Crankshaft Position Sensor and did some research on its location, replaced it and car started right up. (24' extension needed for socket wrench). I also have only changed oil, spark plugs before and know little about cars, but it took longer to research than replace part.
Hope this helps

 

I have searched and read tons of interesting things. I did find the post about testing the CPS with an ohm meter and also with a volt meter. I have only casually looked at it though, had to travel out of town for work and havent had a chance. On mine, the wiring harness looks as if it disappears back inside the transimission/drive shaft tunnel area. I'll have some time tonight and the next couple of days to get underneath and look. I did try and swap the fuel pump relay with another known working one to no avail but not the ASD relay. I'll try that as well. Thanks

 

You should be able to crawl under jeep from drivers side right between the front and rear door about 2ft in, look forward and you should see CPS. The cable from CPS is only about 8"-10" so you should see it from that location also. Use a 24" extension w/ 13mm socket to remove 2 bolts on CPS. There is one bolt (different size) you should remove first on mounting bracket where CPS connection is located (other connection right next to it on same mounting bracket).You can remove connection first to test w/ ohm/ voltmeter before removing CPS. I did meter CPS first, did get resistance, but wasn't 100% sure what I was looking for. Tested for AC voltage as I tried to start engine, but saw no voltage. I bought part for about $90 at autozone, compared resistance first (since can't return part after installing it)and did not match up. At that point although I wasn"t completely sure, I figured since everything I had read about CPS seemed to state that they go out usually at around 140,000 miles I might as well change it and it solved my problem.
Check out pics I put on my "album" to get an idea of what to look for

 

Thanks for the pics. I think I'll give it a go this weekend. I had a friend of a friend come over last night. He has several certifications etc ASE or whatever but had a stroke not long ago and is just now getting back to where he can work somewhat. He tested everything possible and determined it is the CPS. He couldnt physically get under the Jeep and change it though.

 

Success! Swapped it out yesterday evening. First crank, fired right up.

 

Congrats!!! your now certified....on to the next problem.
Any advice on the cylinder misfire problem? I have engine light on with codes P0300 (random misfire detected), P0304 (cylinder 4 misfire detected), and P0305 (cylinder 5 misfire detected). Not sure were to start troubleshooting problem other than changing out Bosch spark plugs which I have read can cause problem.

 

I went through the random cylinder missfire thing as well but apparently it has cleared up after I changed the CPS. There was one specific cylinder that is prone to carbon buildup or something. I think cylinder 3. There was a technical service bulleting released by Jeep on how to clean the intake etc out with some form of cleaner they sell. I can't remember anything more specific about it. I had always wondered if seafoaming would clean that out.

 

Thanks for advice, found tech bulletin but thought I would start w/ the "easy" stuff like they say before I tried that and since I was not getting missfire code for Cylinder 3. First thing I did replaced the new Bosch spark plugs I had recently put in with the cheaper Champion copper brand ($2/each), since I have read that the Bosch spark plugs don't seem to work well w/ this type of jeep for some reason. I then put a bottle of Lucas Oil fuel treatment ($5)into gas tank before filling up tank. Then disconnected battery for a few seconds in order to turn off engine light, drove car around town a bit next 4 days (making sure to let it warm up properly before driving), in order for the computer to build up enough info. to complete necessary "trip cycle" so it could pass necessary Diagnostics test in order to pass my Smog Test. Not sure which of the two things I did solved problem, but neither of the 3 Cylinder Missfire codes I had have returned.....at least not before I was able to finally pass my Smog Test.

 

Ok I've change CPS and the camshaft sensor but mines still firing through the intake I've had it tdc and redone it but it still won't start I've changed the timing chain and did everything again but still won't start do I need to reprogram the CPU?