j0eridesbikes

alrite i have had this problem for a long time and we cant figure out what it is my jeep is a 96 cherokee straight 6 ill drive it for awhile and the temp will stay at normal 210 then ill go to stop at a redlight or stopsign and it was shut off and not turn back on till the temp gets down to around 100 or if i turn it off and go back to it to start it again i have check engine codes but its only for evap and nuetral safety switch ive already changed the coil, and distributor pickup cant figure out why its doing this any help would be great thanks

TheJerm

Sounds like the CPS (crank position sensor).

j0eridesbikes

thats what some people i know were saying but wouldnt that not allow the jeep to start at all i was told it could also be the computer

TheJerm

True when mine went bad it would at least still start but die as soon as i put load on it (put it in gear)

j0eridesbikes

maybe ill change it but i realy dont think thats what it is and its something that isnt giveing it spark cuz it gets fuel

j0eridesbikes

anyone have any ideas i need to get this thing running right again

TheJerm

There are two sensors that control spark. The crank position sensor and the Camshaft position sensor, which is in the distributor. Could test them to see which one is bad. I dont have the link but a simple search should give the voltage range for the sensors.

How are you getting the codes?

j0eridesbikes

they would make the truck just shut off like that and not turn back on till the engine got cooled down?

TheJerm

Yea they most likely have a heat soak issue, where they work find cold but fail when hot. I'm not 100% but if your not getting spark when this happens i would look there. One sensor controls when it actually sparks and the other controls the timing advance, or something like that. I would search for those common issues, I've never had it happen to me.

j0eridesbikes

i just changed the coolant temp sensor today didnt fix it and the truck idles weird to like revs bounce around when stopped gona try the cps tomorrow i think

tjwalker

The #1 cause of thermal (heat related) failure on the 4.0 is the crankshaft position sensor.

Buy it from Jeep. There is no lack of threads of reliability issues with some (not all) aftermarket crank sensors. I buy plenty of aftermarket parts, but I buy the crank sensors directly from Jeep. Well worth the extra money.

FL Denmark

x3 on cps. the problem is that the internal resistiance changes when the sensor gets hot, sometimes it completly disconnects or shorts. that will affect the output of the sensor, to a point where the ecu cant use the signal, and the engine dies. when it cools of, the signal is inside the tolerance and the engine can run again.
i would also recommend a oe jeep sensor

good luck

j0eridesbikes

thanks guys im gona change the crank position sensor do you know how much the dealer will charge for one?

TheJerm

idk usually when the CPS goes bad it will still start until you put a load on the motor aka put it in D. Then again it does like your problem but could also be the camshaft sensor.

I never bought the chysler sensor, 30k miles later its fine (not mine anymore but a family members)

Lane Woods

Did that end up fixing it? Very curious