03 WJ die's?

[jeepgldgr]

This just started to happen I'll be driving down the road and she die's as if I turned off the key. If I let it set for 10 minutes or so she fires right back up and drives fine. Now yesterday after waiting it started and only ran for about a 1/4 mile then died again but after waiting another 10 min she got me back home no issues. This problem has me stumped as the engine runs fine otherwise smooth as silk no misses and no rough idle :brickwall: :brickwall: :brickwall:. Any help would be greatly appreciated thank's. "03" WJ 4.0L, select trac, 75,000 miles on er.

[4.3LXJ]

This sounds like the infamous crank position sensor. They can go completely all at once, but more commonly they do this intermittent death. Fairly easy fix.

[Mudderoy]

This sounds like the infamous crank position sensor. They can go completely all at once, but more commonly they do this intermittent death. Fairly easy fix.

Yeah I agree, it's a very common thing on the 4.0L engine. Without the CPS signal the computer doesn't know when to fire the spark plug. Great way to disable a vehicle too! :D

[jeepgldgr]

So the cps can take a crap them come back to life allowing me to restart and run then? I thought when they go they go. Thanks for the quick response funny my old 88 renix isn't giving me this trouble now the wife is driving it.

[Mudderoy]

So the cps can take a crap them come back to life allowing me to restart and run then? I thought when they go they go. Thanks for the quick response funny my old 88 renix isn't giving me this trouble now the wife is driving it.

There are several things that can be causing you a problem, but the CPS is very common. There is a piece of metal welded on the fly wheel, and as it comes around the CPS magnetically "sees" it, and sends a signal to the computer. If the CPS is flaking out who knows when it will send the signal, or more likely if the signal is the right voltage. Also it could be the connection between the CPS and the harness. I would unplug and plug it back in. In fact I would try that the next time it dies, instead of waiting 10 minutes for it to start. If you can unplug and replug and it starts right back up you might have found the problem.

[4.3LXJ]

The CPS is as stated a magnetic sensor. It needs voltage to work properly and then that voltage needs to be interrupted as the metal on the fly wheel passes it. Heat and long use affect this process over time. Either the CPS has too much resistance or it no longer senses magnetism and will cease to signal the ECM.

Just as a personal opinion, these should be changed when doing a tune up along with the O2 sensors which also commonly wear out and fail.

[Mudderoy]

The CPS is as stated a magnetic sensor. It needs voltage to work properly and then that voltage needs to be interrupted as the metal on the fly wheel passes it. Heat and long use affect this process over time. Either the CPS has too much resistance or it no longer senses magnetism and will cease to signal the ECM.

Just as a personal opinion, these should be changed when doing a tune up along with the O2 sensors which also commonly wear out and fail.

That's a great idea, but that would be ummmm $450 tune up using Chrysler parts.

[4.3LXJ]

That's a great idea, but that would be ummmm $450 tune up using Chrysler parts.

True. However on the CPS, if it was changed on some schedule, say every 100K, the likelihood of it failing would be reduced even with other brands. I know there is an issue with off brand O2 sensors, but I have one that is supposed to be exact factory specs. Forget the brand though.

[drakan1908]

My wife had a Plymouth mini van that did this and it was the fuel pump going bad. I traded it in. I hated that thing!

[TrystanZ24]

The wife's 99 WJ started doing that too, so we changed the cam position sensor and all is well. I got it for like 16 bucks off of amazon.com.
Now The wife loves me again. :love0007:

[jeepgldgr]

CPS was the culprit $30 and 2 hours labor in a parking lot after driving it for 20 miles at 93 degrees she was freakin red hot!!!! multible burns and blisters not as easy of a fix as some has said was not easy getting it back in especially the clip on the top and getting the bolt back in just isn't any room to get your hand in there and move it around. Got er done and learned another 4.0L lesson and thank's guy's for all your help and quick posts:thumbsup:

[oderdene]

CPS was the culprit $30 and 2 hours labor in a parking lot after driving it for 20 miles at 93 degrees she was freakin red hot!!!! multible burns and blisters not as easy of a fix as some has said was not easy getting it back in especially the clip on the top and getting the bolt back in just isn't any room to get your hand in there and move it around. Got er done and learned another 4.0L lesson and thank's guy's for all your help and quick posts:thumbsup:

nice to hear that, congrats for fixing and driving again

[4.3LXJ]

So the next question is to see what the stored codes are. Done that yet.

[Mudderoy]

True. However on the CPS, if it was changed on some schedule, say every 100K, the likelihood of it failing would be reduced even with other brands. I know there is an issue with off brand O2 sensors, but I have one that is supposed to be exact factory specs. Forget the brand though.

Oh yeah 100k swapping of the CPS is a good idea, hell it would be worth it to change it before a long trip even if you weren't at 100k yet.

I was hopeful that the Chrysler O2 sensors would improve my gas mileage over the Bosche(sp?) that I put in there at about 100k miles. I didn't see any change. The Bosche were about $60 each and on my 1998 there's two. I think the Chrysler CPS was around $135.

[jeepgldgr]

So the next question is to see what the stored codes are. Done that yet.

Yes I did only stored code was the cps failure wondering if I should start thinking about the 02 sensors next even though I'm just at 76,000 miles? hate to just replace things I have the if it ain't broke don't mess with it mind set.

[Mudderoy]

Yes I did only stored code was the cps failure wondering if I should start thinking about the 02 sensors next even though I'm just at 76,000 miles? hate to just replace things I have the if it ain't broke don't mess with it mind set.

Check the connection to the CPS first.