askingxforxit

Started up and ran fine in the street and on the freeway. When I got off the freeway and came to a red light it slowly stalled out. I've had the xj for just over a year and have cleaned the IAC twice. I'm in a parking lot right now about to do surgery.

askingxforxit

Took off the iac to check and looks good. Hooked up my code reader and nothing came up. Started the xj and it stalled. Started it again, gave it a good rev and now it's sustaining idle between 665-701 rpm. Seems a little low but it's idled that low since I've owned it.

askingxforxit

Xj started up and ran just fine today. Idle is still low around 650-700rpm. Any ideas what could have caused it to stall last night?? And what should I be looking for as far as numbers go, when I have my scanner hooked up showing live running data??

tjwalker

Unexplained stalling can be the start of a problem with the crankshaft position sensor. It is the most common engine management sensor failure on the 4.0 If the signal from this sensor doesn't reach the computer, you will have no spark and no fuel getting to the fuel injectors. Search for lots of information about it.....

askingxforxit

Since its most common I'll probably replace it anyway. 162k miles on it I'm sure its time to start replacing all kinds of things.

tjwalker

Normally, I am not a fan of fixing something before it's verified broken, but in the case of the crank sensor with the 4.0, it is NOT a bad idea. Especially if it is the oem crank sensor with 160k on it.

Take my advice and buy it directly from Jeep. There is no lack of threads of people having trouble with some (not all) aftermarket crank sensors.

The Jeep crank sensors are a little more expensive, but they are absolutely worth every penny more.

askingxforxit

Cool thanks for the tip. I'll stop by the dealer tomorrow. I'm thinking too that maybe the fuel filter needs replacing...i hear its a pain :/

Fsher21

Could be a marginal battery too, next time you are bored and drive by a larger auto parts store, they will load test it for free. Can't hurt right?

askingxforxit

True, though the battery is a die hard and less than 2 years old. Not saying I won't count it out though.

askingxforxit

Seems like I'm also having a dip in. fuel mileage.

ol'DixieJeep

tune up. might be distributor plugs and wiring... check timing and replace cam position sensor, its not very expensive. i have coil packs. it ended up being my distributor thingy, was more often though.

ive been seeing a common problem with this type of thing.

askingxforxit

I have coil packs also. CPS will be replaced very soon. Also thinking of getting a valve job. Anyone know if doing the valves myself would be too difficult??

ol'DixieJeep

theres a poormans way of doing it using the valve and some type of sandy grease stuff. ive seen it done. if your taking the head off port the bowls atleast and port the intake and exaust ports if you want. be careful on the bowls, just smooth them out and polish the walls.


i had my buddy fully port mine for my 4.7 its a HUGE difference!!!!

askingxforxit

Nah I'm not going that far with it. If the time arises and funds permit when the engine goes completely to **** I'll just swap an LS1 in it bwahahaha!