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Dead Xj

itbrokeagain

NAXJA Forum User
Location
Amelia Ohio
My 98 4.0 auto started acting funny today. A few times on the way to work it cut out (completely died, but not missing) but came right back and ran fine. Did it again to me once on the highway tonight and then about a minute later died and would not restart. No missing just quit. Right now it is still sitting on the side of the highway. I will load it on my trailer tomorrow and bring it home. I didnt hear the pump coming on when I turned the key but I was also on a busy loud highway. Where do I start when I get it home? So far fuel pump and crank position have been mentioned. Any other suggestions?:hang:
 
Crank sensor is the primary suspect. Without it, you will not have fuel going to the injectors (may have good pressure in the fuel rail) and you will not have spark.

If you buy one, buy it directly from Jeep. Aftermarket crank sensors are kind of "hit and miss" with a lot of miss. Well worth the extra $20 or so in longevity and reliability.
 
I am going to change the cps. I released the schrader on the fuel rail and I had pressure. Just to be sure I turned the key on and got pressure. I loaned out my multimeter so I can't check it but I want a spare for the trail anyway.
 
My Jeep did the same thing. I also thought it was the Crank Position Sensor and replaced it. Jeep ran good for about a month then died completely. Not missing, or rough running. Just died. Turned out to be the cam position sensor inside the distributor. Since it was not receiving a clean signal it was messing with the ECU and Auto shut off.
 
The crank sensor does NOT set a code most of the time. If it is catastrophic fail, it seems to fail so quickly that OBD doesn't pick it up. An intermittent signal is more apt to be picked up by the OBD system.

Wouldn't hurt to check to see if you have any stored codes though. You don't need a check engine light on to have a stored code, and those codes can be very valuable clues.
 
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