2001 Jeep Grand Cherokee Stalling

[shamalex72]

Occasionally when I stop at a stop sign the engine will die and sometimes when I am just slowing down for a stop sign or a turn it will die, sometimes it will restart, sometimes it won't. If it does not die completely it will lose all power as I am driving. I will have my foot on the gas pedal and the gauges will quit and the Jeep will lose all power for a second, without completely stalling. Since it does not do this all the time the mechanic tells me nothing is wrong with my vehicle. We have replaced the battery and fuel pump. Any suggestions on what else to try. (2001 Jeep 4.0L) Thanks

[Glenn_S]

Crank Position Sensor....Been there, done that.

About a $25-$35 part, but it can be a bit of a pain to get to. You need to go through the passenger-side wheel well. It is located in the block. Be careful, it is plastic, and if you break it off, it will cost you a trip to the shop.

Actually pretty easy to replace.

Glenn

[Jim Panfish Uran]

How many miles on it??? Could be the O2 sensor also. I have the same engine in my Jeep, there are 2 of them though and they are not that cheap $75 a piece. THey are on your exhaust pipe, one just coming out of the manifold and the other on your catylitic converter. Same signs mine was showing. Hard to tell if there isn't a check engine light coming on to send a code.

[Jeremy airjer W]

Quote:

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If it does not die completely it will lose all power as I am driving. I will have my foot on the gas pedal and the gauges will quit and the Jeep will lose all power for a second,

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All the gauges go to zero like you shut the key off? Or the tach goes to zero and all the other gauges operate like you just turned the key to the on position along with all the warning lights coming on as it stalls?

Given the history of crank sensors on these vehicle it is likely. typically what they do is short out the supply voltage which is shared by a number of components including the coil if I remember correctly. No power and no crank signal will stall an engine in a hurry!!

The first thing I would do if I where looking at this vehicle and the problem was present (crank no start) is check fuel pressure (should be good since the pump was replaced) next I would check for spark (likely this is not present). As soon as I saw that there was no spark, if this is the case, I am backprobing the connector for the crank sensor to see if there is voltage. If there is none I would unplug the crank sensor. If voltage returns I know the crank sensor is shorted and this should fix the problem. I should note that when checking for power at the sensor you will have to either cycle the key or give it a quick crank to re-enable the ASD relay.

Although O2 sensors get replaced all the time, typically for burnt out heaters and being lazy, they rarely cause drivability issues and are even more unlikely to cause a vehicle to stall. With most new cars having up to four and I think I have seen something about 6 this can get to be a pretty expensive endever.

[Shack]

Airjar,

If eng. dies and will not restart because of crank sensor concern, you should be able to unplug crank sensor and pcm will go into a lip mode. Eng. will start, but run funny and possibley shift funny. This may applie to cam sensor only. I still scratch my head when people would come into dealership with a driveabilty concern (running rough or stalling) and the first thing they say to you is "I changed my o-2 sensors and did not help". I do not know who started this method of diag., but people end up spending more money than they should by "shot gunning" parts at a concern. I do not think there is any service interval on o-2 sensor's yet, but the public seems to think there is. Good luck!

[Jeremy airjer W]

Its airj"E"r !

I don't know who started the o2 myth either.

They will not start with the crank unplugged.

They other thing a do it yourselfer can try is a good throttle boddy cleaning. Pull of the air snorkel at open up the butterfly if its black it you may as well clean it (engine off of course). Carbon buildup can cause issues with minimum air which chrysler bases idle off off. The IAC (idle air control valve) could be carboned up as well. I've had pretty good luck cleaning these and having them work as well.

[Shack]

Sorry . The old throttle body clean. Pays .8 to 1.0 to perform and gets you better gas mileage. I believe Chrysler is the only manufacture you can do this to. I know ford has Teflon coat inside throttle body. Cleaning removes this and manufacture does not recommend. I think cleaning throttle body on Chryslers helps adjust min. air rate. Make sure they remove throttle body. Alot of tech's would charge out gasket, but never remove to clean.

[Jeremy airjer W]

I don't think I have ever seen anybody remove one to clean it. I suppose if it is real dirty its no a bad idea! We still clean quite a few Chevys, Especially the newer pickups and full size suv's. See a lot of sticky throttle plates on those! As far as the fords if its all gummed up, black and nasty it gets cleaned coating or not.

[Shack]

It was part of a service that a couple of dealerships I worked at had been offering. Both Chrysler dealership's had issues with tech's not removing throttle body (cutting corners). It was part of the service they sold and tech's got paid for it. I, my self would just clean with out removing I suppose. Most tech's do say you do not have to remove.

[shamalex72]

My wife brought the jeep in today and had the crank position sensor replaced. So far, so good. Yesterday it stalled three times for her. Hopefully that was the problem and she won't have anymore troubles. Thank You for the suggestions.