steven72192

Was driving my 98 xj 4.0 L the other night on the highway and suddenly I heard a pop like backfire noise and there was no throttle response so I coasted to the exit ramp and tried restarting it and nothing the engine cranked and cranked but didn't turn over I came close a few times but I cranked until the battery drained long story short I got it towed back to my house and know I'm hoping its nothing major. The battery is dead so I put it on a charge this morning so after work I can try starting it again. Few things I checked already I look for codes and there was no codes present while I was cranking oil pressure went to 40 and I also pressed the schraider on the fuel rail and it had fuel in to everytime I pressed it, what else can I check it's just puzzling to me why it just shut off like that any suggestions or has anyone had this problem?

dwright98xj

Almost screams crank position sensor. Did you try unplugging it and cleaning the connectors on the top side of the motor? I've read here a lot that seems to more the problem than the sensor actually being "bad".

steven72192

I have not tried anything but what I listed yet and would the crank sensor fault cause the random die out?

dwright98xj

yup, no signal, no fire. Which is one of the 3 things your missing in order for the engine to run.

NewJerseyXJ609

Do you have spark? This is classic CPS failure. You can check it with an ohm meter.

They won't always kick the cel on.

RTorrez1

Like the others have said make sure you have a good blue spark. If you have spark then check the fuel pressure. Just because you push the valve and you have fuel come out doesn't really mean to much if you don't have the right pressure. On the 98 you should have 49psi + or - 5psi.

steven72192

I will be checking the CPS today after work what's the spec if I ohm it out what should I be seeing?

Parsnip

Honestly, do a voltage check on it as opposed to ohms. Ohms will let you know you have atleast a good circuit but voltage is what matters for the actual firing iirc

steven72192

Okay how can I do a voltage test key on? And what are some numbers I should be getting

steven72192

Crank sensor not the problem I bought a brand new one thinking its a common problem on these Cherokees so I put it in and still doing the same thing cranking it wants to turn over but it didn't any other suggestions

freegdr

Crank sensor would of set a code ....have you checked all fuses yet not sure if 98s the same but older xjs o2 wiring would fall and rub on rear ds causing a dead short and blowing a fuse in pdc under hood causing a no start think it was a 15 amp.

freegdr

Check fuse 19 its 20 amp in pdc under hood...

Spoolproof

Check for vacume leaks , if it has fuel resistor ballast clean the terminals. And pull idle air control and clean it all easy free things to try that might help.