94 xj with 96 engine 4.0 yada yada

Anyway so my other post was concerning the battery drain. I do not have the time to follow it right now but I do have a big issue. Basically I come home from work, Or I have not touched the jeep in a day or so.
So I do experiments. She always starts... runs strong. Keeps running. No issues. You have to wait until she reaches full engine temp. Still no problems, full of life...keeps running. So if I shut her off, she will not start again. Turns over and over and over and I tried all the tricks..flutter the throttle, full pedal down to clear the fuel. Nothing. Now I know it is not fuel. I did the ghetto pressure test by priming the pump and pressing the schrader valve on the fuel rail..shot out like a nice rocket of decent pressure. I am really trying to figure out what in the ignition system cuts off power when the engine is warm and on a restart? I Plan on getting igntion test equipment...pulse light tester, spark plug line test, but I think this is something else someone here may know. Please help. I am truly grateful.

 

Maybe I wrote too much. Lemme sum up. Is there a simple answer to this question... What would cause the engine to no longer start after it is fully warmed up? Just continues to crank. ASD relay kicking in due to some thermal overload or something weird? Any ideas are appreciated...off to work..yay work.

 

Put some ice cubes in the radiator when it gets too warm.

Is the coolant temp sensor still in spec? Maybe it could be wrongly fueling when it warms up due to a wrong reading.

 

This isn't an issue that has one overwhelming solution. This is an oddity that will have to be troublshot.
I'd start by obtaining the starting/charging diagram for the wiring. Try bypassing the Auto-Shut-Down relay with a paperclip or wire first. Go from there. It could be heat changing the quality of a connector for a sensor. It could be very difficult to find without isolating the issue within a part of the starting system first.

 

That only says the fuel rail has fuel, not the cylinders.

 

Will it run correctly for as long as it stays running? but then won't restart? Or does it die (or run poorly) when it gets warmed up?

 

It runs perfect until you shut it off. It could go for hours or until it runs out of gas. Shutting it off is what prevents it from restarting. I could go outside now and it will start right up and run fine.
Once warmed up it just won't start. Endless crank without a notion or startinessss

 

Dangit I was hoping it would finally be something easy to replace,,,but nothing has been easy thus far, why start now...

 

You own a Jeep Cherokee XJ

 

Actually I am pretty sure a Jeep Cherokee XJ owns me......

 

Can you start it, shut it off, and then restart it successfully...as long as it is still cold?

 

I have not tried that yet. I can try that tomorrow. I think so but of course I need to do the test.

 

I'd suspect a failing crank sensor. They can get weak when they get warm, and the output from them is at it's lowest when cranking. If the signal is too weak, you won't have spark or fuel injectors going.

 

^^^^^

When my CPS started going bad, 4 times in a row the engine just shut down after driving about a half hour. Each time going about 65 MPH on the interstate. Damned inconvenient. Fortunately would start right up after a few moments. It wasn't until the last one that I got the engine code.

 

BTW do you get an engine code with that? Would that be an 11?