Hi everyone,I have a Cherokee 2000 xj 4 x 2 4.0 engine.It works fine until it gets hot and suddenly stalls.After maybe 10 min cool down it starts again as if nothing had happened.I have done the following.
1) changed CPS for OEM Mopar
2) changed radiator,water pump and hoses no leaks visible.
3)changed complete motor including head,block, Pistons ,rings etc.
4)Had complete transmission overhaul.
It happens after a while in traffic or slow going on dirt road,engine temp gauge marks normal reading,pressure gauge is ok.And suddenly without warning it will stall,no warning whatsoever.
I don't know what else to change,any ideas?.After changing engine,and everything else I have mentioned any fix will be cheaper

 

Compression, mixture (fuel air), ignition.
let's forget compression for now.
Possibly heat related as you say that is the condition that is concurrent.
That leaves loss of ignition or mixture.
Vapor lock? Or heat related electrical gremlin? I am not inclined to think items 1, 2, 3 and 4 in your post have anything to do (just history update) with this issue. How long have you lived with this condition?

 

I’d think either vapor lock or has the stall always happened with the A/C on? Maybe the A/C is seizing randomly and causing a stall. How hot are we talking?

 

If you can, check your fuel pressure when it dies. Also check for spark. Seems to me it's a heat related issue. Normally, we'd all first cry CPS, but you just changed it for a Mopar.

Still, are you sure the CPS is genuine? Where did you get it? Too many fake parts to believe the only the label on the box or the sellers claim.

Determining if the stall is due to loss of fuel or spark is key to tracking down the culprit.

 

when the engine was rebuilt were ALL the sensors replaced? This sounds like a crank position sensor - when they go bad, they only work till they get hot

 

THANK YOU SO MUCH!!!!!. After 3 months of going practically insane over this issue .I thought that something which I assumed was OK, obviously was not.
I went back to the most common cause that is the CPS which I had ordered and bought because it was about 20 bucks cheaper than the other offers and was advertised as "genuine Mopar CPS" .It arrived in a perfectly sealed box and bag with MOPAR logo and part number embossed.
Now let me tell you that I am in Mexico and over here it is not as easy al lifting the phone and ordering something,this purchase was made after research and discarding obvious offers that were clearly scam.

My test was as follows:
I went to a desolate street and simulated heavy traffic for maybe 40 minutes untill suddenly the motor stopped and I could not start it, immediately I grabbed a thin hose and soaked the CPS with water and went to start the engine AND BEHOLD !!! ,it started immediately!! .Since I'm am engineer I decided not to take this test as completely valid and repeated this test again with the same input l parameters and the result was the same.....immediate startup!!!
I don't know if this is a conclusive test,please let me know if there could be some other issues that I should check.
I have to acknowledge that age makes me more stubborn ; I dismissed de CPS sensor solution right away untill someone suggested of a fake CPS.
ANY THOUGHTS are welcome.
Best regards and thank everyone su much!!!
If someone comes to Guadalajara,give me a mail and we'll go get some beers or tequilas.