Rush

Hello guys, i found this forum while searching for somewhere to ask about the problems i've having with my '98 XJ. Its got the 4.0L / auto with about 180k miles on it.

These problems started a few weeks ago and its been down ever since. It started on day i went to drive to town, i made it not even a 1/4 mile up the road and it just died, no sputtering or anything, it just died like someone turned the key off. It would not start at all after it happened, and acted like the battery was dead, so we towed it back to our house and left it sit. I came back home a few hours later and tried it, and it started right up.

Now, it will only run for a few minutes at a time, then it will rev up on its own, and then just shut off. It won't start right away either unless i leave it sit for a couple minutes. I checked for spark right away it shut off and it was getting none, but after a couple minutes it will fire right up with good spark (bad coil maybe?). It will run good for a while then when i shut it off it won't start again about 50% of the time.

I was looking at it today, and it started sputtering while idling and it started trying to suck in a huge amount of air, after that it revved way up and went back to normal idle. I tried the key on-off method to see it would display and OBDII codes (it has the digital odometer) but it showed nothing. I know for a fact that it should at least be giving me a O2 sensor error, and my check engine light has been on for the past 2 years (O2 sensor again, got my exhaust redone with no sensor now) and it has been running perfect all that time with no O2 sensor with normal gas mileage, but as soon as i started having this problem my check engine light went off and hasn't come back on since, which i assume is why its not giving me any OBD codes.

Anybody have any idea what the problem might be? Any thoughts or suggestions are appreciated!

sflxj

try a simple tune up cap, rotor, coil, wires, and plugs. you could have small cracks in the cap that allow moisture in and/or your rotor could be bad. also your coil could be bad. i strongly suggest doing it all at once it's cheap and worth it.

upritexj

sounds alot like a crank sensor issue.

1jeepman

98 models do not require key on and off method to check the codes, I believe 96 and up have the OBD port under the dash drivers side to check with a gauge. Indeed sounds like a crank position sensor issue to me as well and if you aren't lifted it is a booger to get out and back in.

Rush

The cap/rotor and wires were changed last year so they should still be good. I never got to the coil though, hell it might even be the original one.

Yeah but i don't have a OBD reader to plug in, so they key on/off was the easiest for me.

That's two votes for the crank sensor then so far, i was hoping it wouldn't be since it looks like it will cost me $80 for a new one. It's lifted 3" though with 31" tires so it shouldn't be that bad to get under it.

SeriousOffroad

Try unplugging the CPS and cleaning the contacts with some electrical contact cleaner and add a smal dab of dielectric grease.