99 WJ 4.7V8 Frequently shuts off while driving??

jjwells21 · 09-21-2009, 07:53 PM

Hey guys I have a 99 WJ with a 4.7 v8 and the past few weeks it will frequently shut off while driving. It only showed one code of engine speed sensor/crank position sensor. so i replaced it and yet the problem still continued. now when it shuts off all the guages go to 0 and all the instrament lights come on. you can try and start the car over and over but it wont actually start until it seems to either cool off or the system recycles itself. im not too sure what else to try. i have replaced the crank position sensor, cam position sensor, fuel filter, coolant temp sensor and checked the fuel pressure which is normal. this continues to be a puzzling problem especially since there is no check engine light that comes on when it shuts off which leaves me scratching my head. any help with any other possible reasons would be greatly appreciated.

jeepheller98 · 09-22-2009, 12:18 AM

have you looked at the wires to the crank sensor?... how does the connector look? is it corroded, or maybe you got a defective sensor.. these are the exact syptoms of a CPS.

Laidback · 09-22-2009, 12:21 AM

Mine was doing the same and gave me the code for the CKPS too, I cleaned the battery terminals/connectors up and it hasn't done it since. (2 or 3 months ago)

There is a thread on here where somebody replaced their CKPS and the new one was faulty, when it got hot it stopped working, after it cooled down it was ok again.

So, do you have exactly the same symptoms now as before you changed the CKPS? How long will it drive before it shuts off? How long do you have to wait before it will start again?

jeepheller98 · 09-22-2009, 12:25 AM

also when you replace any sensor you have to rest the computer.... disconnect neg cable. put foot on brake, and keep key turned all the way for 30 seconds

CanadianZed-J · 09-22-2009, 07:20 AM

Quote:

Originally Posted by jeepheller98

also when you replace any sensor you have to rest the computer.... disconnect neg cable. put foot on brake, and keep key turned all the way for 30 seconds

What's the idea with holding the brake and turning the key? To discharge any capacitors faster or just good luck folklore?

CZJ.

BTW, back in the day my dad had an '87 Aerostar that did this. Pretty sure it turned out to be a bad gascap not letting air into the tank. Once removed, the van ran fine. I highly doubt your solution would be this easy, but you seem to have tried everything else.

Ved · 09-22-2009, 07:41 AM

I'm having the exact same symptoms as you describe. My CPS arrives today by way of UPS. I hope I don't have to chase this gremlin till my wallet weeps. So many horror stories related to this issue.

So far I've replaced fuel filter, Dist cap & rotor, Plugs & wires, and disabled the factory security system to no avail.

It's so random that there is no pattern as to when and where it shuts off. Doing 60mph, stopped, letting it warm up in the driveway... anytime, anyplace. Weird part is, I usually just pull right over when the engine stalls, but this last time, I put my foot in the gas when it stalled, and like a switch, the engine came back on and drove just fine. Sadly this Jeep has been reduced to just picking my daughter up from school like 4.5 miles away, but now it's even doing it once or trice in just that small trip.

I'm not getting any codes other than code 12 (battery has been disconnected recently) which is true.

**Double E** · 09-22-2009, 10:28 AM

Battery may also be the culprit here. It will barely idle with a bad battery and if the battery is disconnected when it is running due to a bad cable or terminal, it will cause a shut down. If there's a bad cell in that battery, it can cause this and possible an intermittent issue.

Try one from another vehicle first to test or just replace it before you throw more parts at it.