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please help....again

L

lost on a trail

NAXJA Forum User
Location
missouri
ok,awhile back i posted about problems my jeep was having. it was having problems starting after it had run for awhile. i finally got to replace the crank shaft position sensor and it ran and worked beautifully....for about a month...now its doing it again. did i get a bad sensor? i replaced the broken exhaust manifld also so there isnt excessive heat getting to the sensor. i cant afford a $75 sensor every month just to drive this thing. it doesnt throw a check engine light. does anyone have a clue....if it continues i will junk the jeep and move on to something else,i hate to be that way but i need something dependable.
 
Cherokees are known to be very dependable, usually. However, electrically speaking, they seem to work a bit different than most engines. Actually, once you get the hang of working on them, they are usually rather easy to diagnose.

If you have a multi-meter, this information at the below link will help you troupleshoot most electrical issues, assuming you don't have an HO engine. If you do, I believe there is an alternate page on this site. I have found this information to be so informative, that I printed out a copy and keep it in my glove box, in case something happens on the trail. Using the information, you can diagnose most of your electrical issues, to determine the cause of your symptoms.

http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

Best of luck!
 
Did you route the CPS wire through the clip(s) on the firewall to keep it away from the manifold? wires can, and do melt.

...and yes it's possible to get a bad part but something isn't right, check the connector, wires etc. Make sure it all went back together the right way
 
its a 92 with the h.o. and when i put it back together i made sure everything was tucked away real good...i worked at a restoration shop for 11 yrs so thats kind of one of my pet pieves...lol. i just dont understand how the sensor could work for a month and go bad again. its doin the same exact thing as before...if it runs for about 30 minutes or more when you shut it off it wont start until its completely cooled again. the other sensor got so bad it would just die while idling after about 10 minutes. i changed the cps and everything was great...until tonite. i know the cherokee is on of the best vehicles out there....i have owned 6 of them....im just tired of having to work on them just to go to work and then work on them after work to get back home...lol
 
Check the ignition coil and fuel pressure? Starting to sound like (a) heat related temporary failure of the CPS (hopefully not, it does suck to keep buying them, I'd try a junkyard one next, buy 3 for 5 bucks and one of em is bound to work) or (b) heat related coil failure or (c) enough crap floating around in the fuel tank that it blocks the pickup after running for a while, then when you turn it off for a bit it slowly falls back off so the fuel can get to the pump again.
 
Next time it happens, throw a cup of water on the CPS and see if it starts up. If it does, it's the CPS. If not, look at some of the things others have suggested. I think 92 was one of the years with crappy coils though.
 
ok,for lack of time....can someone please tell me how to troubleshoot this this problem? what sensors do i need to test and how....what about map sensor? how do i check the coil? im pretty sure its not a fuel problem because when i replaced the srankshaft position sensor the first time it solved the problem...now its acting exactly the same again. i have limited funds and limited time so i need as much help as possible
 
ok,so i talked with NAPA and they said the sensor has a 12 month warranty. they said to bring it in and they will replace it but wont have one til wednesday. so thats what im going to do....besides having the wires too close to the exhaust,what else will cause a crankshaft position sensor to fail? my wires are no where close to the heat so i wonder if something else is going on.
 
Get it running, use a heat gun or blow dryer on the COIL to see if that is the problem.
 
cruiser54 said:
Next time it happens, throw a cup of water on the CPS and see if it starts up. If it does, it's the CPS.
Click to expand...

Really?? Why? Does it make better contact? 1 cup?

...and unplug, clean and re-plug the connector?

lost on a trail said:
ok,for lack of time....can someone please tell me how to troubleshoot this this problem?
Click to expand...

Spark, fuel & air. Which one is missing?

lost on a trail said:
....besides having the wires too close to the exhaust,what else will cause a crankshaft position sensor to fail?
Click to expand...

Poor manufacturing, not installed properly (e.g. not tight enough, crooked), dirt & grime, bad connector etc.
 
i exhanged the sensor today..got it running right now to see if it fails again. i cant find the thread on here for testing the sensors and electrical for a H.O. equipped vehicle.
 
ok it ran for 45 minutes then started acting up again!!! whats next? i dont have an ohm meter so how can i test stuff like the coil. i would pull the one off my other jeep but its an 89 and different
 
i went and bought a multi tester....i tested the coil....at the plug i am getting less than 1 ohm....at the coil wire side i am getting 13.4 ohm( ohm meter set at 20k). where now...are these numbers good or bad...i cant find any info on here without sitting here for hours trying to swimming thru all the posts....i need to have this thing fixed quickly or risk loosing my job
 
ParadiseXJ said:
Really?? Why? Does it make better contact? 1 cup?

...and unplug, clean and re-plug the connector?
Click to expand...
temp related failure. If it revives after being cooled off, it means the sensor has partially failed and goes into failure when it gets past a certain temp.

As for the coil, I would check it by putting a spare spark plug on one of the plug wires and holding the outside of the plug against the block, if the spark is lousy there is your issue.
 
Following info from the 93 FSM (don't have a 92):

IGNITION COIL RESISTANCE - Ohms @ 68 F (20 C)

Application Primary Secondary
Diamond Coil .......... .97-1.18 ......... 11,300-15,300
Toyodenso Coil ........ .95-1.20 ......... 11,300-13,300
 
joe_peters said:
Following info from the 93 FSM (don't have a 92):

IGNITION COIL RESISTANCE - Ohms @ 68 F (20 C)

Application Primary Secondary
Diamond Coil .......... .97-1.18 ......... 11,300-15,300
Toyodenso Coil ........ .95-1.20 ......... 11,300-13,300
Click to expand...

so i am supposed to be getting somewhere between .95-1.20 ohms at the plug?..i think i was getting like .3 or .4 but the ohms at the didtributor side of the coil was in the range you have listed. i cannot afford to buy a coil and find out its not the problem....and there isnt any in any of the salvage yards around here. i have checked. work at a farm and home store so im not rolling in cash....was hoping to get this fixed or im going to sell it.
 
so i just run the jeep until it failed again....almost exactly the same amount of time each time it does it. i pulled a spark plug and wire and grounded out the plug. had the girlfriend turn the motor over while i watched the spark...it was orange...shouldnt it be blue? it is getting spark after it shuts down but im not sure its getting enough. i have no clue what to check for..so im hoping someone here can help out. i was a mechanic at a restoration shop for 11yrs but it was with pre-computer control.
 
HOT, blue color, SNAPPY spark.

Wait for it to cool, then start it just to make sure it runs and shut it off. Now, use a heat gun or hair dryer on high, heat up that coil. Once it is good and hot see if it will start and run.

Good luck.
 
after it cools it gets the same color of spark but maybe a little more pop to it and it seems to spark quicker than when it went into default. i dont have a hair dryer(hell i dont even have hair...lol) or a heat gun. if the spark is supposed to be blue it sure didnt look it to me. how do i test the camshaft position sensor that is in the distributor? what kind of ohms am i suposed to have there?
 
ok,i got a coil from a friend today,i know the coil is good. we too k it off his jeep that has no issues. it does the same exact thing again....runs for about 40 minutes then starts to stumble and cut out and then dies. i honestly dont think this is a fuel problem. if it was sucking crap up in the tank...would it take different amounts of time for different amounts of fuel.... a full tank should take longer to accumulate on the sock than a 1/4 tank. so whats my next step, this is running me nuts! do i try to replace the pick up in the distributor? or am i correct in thinking that the pick-up fires the coil...so if the coil is still getting fire after the engine dies and wont start....then the pick up is still working,right? please help...i need this jeep running
 
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