Engine wont run, please help me.

98 XJ 4.0 AW4 200kish miles.

Well I was on a road trip from Florida to N. Carolina Friday night. I pulled in to get gas ans let my GF take the wheel in GA. 5 mins later the engine just cuts off and we coast to a stop. It has never done this before.

I checked the fuel rail and even pulled an injector and fuel flows when it is cranked. Pulled a spark plug and there is spark. The engine cranks over. I checked the oil and it has the proper amount. The engine did not over heat. The belt is intact and there are no engine codes being thrown. I even scanned the XJ just in case the check engine light did not register a fault, and still no code thrown. I opened the oil cap and had my GF crank the engine so I could see if the rockers and springs moved (determin if timing chain/belt snapped) it all moved with the cranking. I am at a total loss at this point and am stranded. Please give me any thoughts or suggestion howver odd they may be. Thanks guys!

fuel flowing out the rail? or pulsing out the injector? big difference.

The cam sensor in the distributor tells the PCM when to fire the injectors. bad sensor= no injector pulse = no start

Well I pulled the hose from the rail and when the engine is cranked, fuel flows from the hose where it would connect to the rail, so I put the hose back on. Next I pulled the rail off the intake and left the injectors on the rail and the electrical conectors on and when the engine is cranked I get spray from the end of the nozzle that could normally be plugged into the engine.

edit: I did replace the entire distributor last year including the sensor in the deistibutor. (all one big unit)

got spark, got fuel all you need is compression. timing chain jumped?

Digger87xj said:

got spark, got fuel all you need is compression. timing chain jumped?

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Well I am headed to the auto parts store to rent a compression tester to see if thats it. I'll report back shortly, thanks!

Just Randoms / Maybe's:

- Bad fuel?

-Do the reset - disconnect batt neg 1 minute
( may just be confused?)

-Vapor lock from stop? cool it down, try again.

-Give the connectors for CPS, Throttle area a 'replugsins'

- Swap around relays of same type in PDC.

GOOD LUCK!!!
Orange

Even though you said there is spark at the plugs; I would unplug the Crank Position Sensor connector (at end of fuel rail on top of intake manifold near firewall) wait about 30-60 seconds and reconnect.
If the CPS is going bad your engine should start unless it has fully gone....
If you have a multi meter place the meter on Ohms and probe the sensor terminals while cranking to see if you read resistance and infinity when the sensor passes the contacts on the flywheel.

98XJFLjeeper said:

Well I am headed to the auto parts store to rent a compression tester to see if thats it. I'll report back shortly, thanks!

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Ok I tested all the cylinders, and they all have the same compression. I had my GF crank the engine for about 10 seconds each and the final reading everytime was 128psi +/- 2psi maybe. Gonna go check the CPS next.

I am having the same problem. Here is my thread, I dont know if it will help you or not. Mine is a little older.
http://naxja.org/forum/showthread.php?t=1026297

98XJFLjeeper said:

Ok I tested all the cylinders, and they all have the same compression. I had my GF crank the engine for about 10 seconds each and the final reading everytime was 128psi +/- 2psi maybe. Gonna go check the CPS next.

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Ok, pull the distributor cap and check the condition of the rotor and cap.

Pull the number one spark plug and rotate the engine until the piston is at TDC on the compression stroke--hold a finger over the spark plug hole and on the compression stroke air will push your finger away from the hole. Now, check the rotor and see what cylinder's spark plug wire contact it is pointing at.

joe_peters said:

Ok, pull the distributor cap and check the condition of the rotor and cap.

Pull the number one spark plug and rotate the engine until the piston is at TDC on the compression stroke--hold a finger over the spark plug hole and on the compression stroke air will push your finger away from the hole. Now, check the rotor and see what cylinder's spark plug wire contact it is pointing at.

Click to expand...

Ok I havent been able to test the CPS next to the firewall, it has 3 wires, and im not sure how to test that, maybe someone could explain in detail or point me to a thread as I didnt see anything in search. I noticed that my sparks from the spark plugs seam weak and yellowish, not the suggested strong and blue. i replaced the plugs, and same thing. Maybe I need another cap and rotor.

Do you have a multimeter with you? Check your static battery voltage between the terminals, want about 12.5 volts. Then check the voltage while cranking the engine, if the voltage drops below 9 volts you have battery issues causing your weak/yellow spark.

Other possibilities--coil, cap, rotor, spark plug wires.

See Tim_Mn's post here: http://www.naxja.org/forum/showthread.php?t=1032597&highlight=crank+sensor