Our daughter bought a used Jeep Wrangler(first one)recently and it stalls out at a light or first thing after starting up. When she starts it and shifts from park to drive, puts her foot on gas pedal, it stalls. Every time, when she puts it in park, it immediately starts back up and then she is able to go on her way. Might not do it again for a few days.
She took it and Carmax looked at it for a couple of days(it did it on them) and no codes showed up at all. They checked everything. They sent it to Jeep dealership, and they had it for couple of days and found nothing. It did not stall on them. She has it back now, and has done it a couple of times since. It always starts right back up. Any ideas guys and gals?
Appreciate it.

Just acquired? How many miles has she put on it?

Could it be as simple as stale or wrong season gas? How long did it sit for sale? Run it nearly dry and fill it with a top tier gas and add some Techron or similar for a tank or three. ~Cheap easy first step if no codes...

More details perhaps as well. Engine, milage...

More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com

Head over to the Wrangler forums. They're full of information and have seen it all.

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Originally posted by PowerSurge:
More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com

I thought that would throw a code... maybe not?

First thought being no code, positive crankcase ventilation valve. (PCV valve). That’s my first thought. I have had more than one vehicle that did the same thing you mentioned.

Very carefully check the wires, especially the ground wires for the ignition. If it is a bit loose, that will cause this.

Like PowerSurge I'm suspecting the Crankshaft Position Sensor. Many times when they fail they go open circuit, acting like the engine was shut off using the ignition switch. Because of this there is no trouble code stored, the ECM "thinks" this is a normal condition.

Crankshaft position sensor (cheap; replace with OEM, not a Duralast)
Torque converter solenoid (cheap)
Torque converter (hundreds)

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Originally posted by cparktd:

quote:

Originally posted by PowerSurge:
More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com

I thought that would throw a code... maybe not?

Sometimes yes, but more than likely not.

Also make sure both battery terminals are connected well and not corroded.

quote:

quote:
Originally posted by PowerSurge:
More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com


I thought that would throw a code... maybe not?

It doesn't really sound like a cps to me, usually they just crank and won't start at all when one of those fails. I've replaced a number of them though, and none has ever set a code. Like everyone else said, they fail so frequently I always carry a spare with me. Buy OEM, the aftermarket ones are even worse.

Look it up on youtube, they are fairly easy to test. There are two different styles depending on year however, so make sure you are looking at the right test.

Check the fuel filters. You might have some clogging going on.

I owned a jeep that did this. After thousands spent it was diagnosed as a neutral safety switch. Can't say for sure if that fixed the problem as I traded it in the day I got it back from the mechanic.

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Originally posted by Perception:

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quote:
Originally posted by PowerSurge:
More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com

It doesn't really sound like a cps to me, usually they just crank and won't start at all when one of those fails. I've replaced a number of them though, and none has ever set a code. Like everyone else said, they fail so frequently I always carry a spare with me. Buy OEM, the aftermarket ones are even worse.

Look it up on youtube, they are fairly easy to test. There are two different styles depending on year however, so make sure you are looking at the right test.

When they fail on those model year jeeps, the symptoms are exactly as he describes. Obviously it could be something else like a bad TIPM, but since it is not throwing a code I would go with the cps first.

Does it mainly do this when it is cold?

I hope that Carmax or definitely the dealer checked for TSB’s. Many times a computer program update is needed to correct some issues like this.

First things first, check all grounds for cleanliness and being tight.

Next, clean the throttle body. A dirty throttle body can stick, especially when cold.

This just doesn’t sound like a CPS. As has been said, they will usually cause a cranking no-start. Or they will start failing as the sensor gets hot.

Another thing to check just for general principles, if this has a Mass Airflow Sensor, make sure that there is no debris that can be getting into the sensor.

Thanks, has 83000 miles on it and she just got it a month ago. Really doesn't do it when it's cold. I can bring these options up to carmax. They said to bring it back in if it did it again. It's done it three more times. I'll check out the forum.

SIGforum is Awesome! 99% of the time the exact right answer is delivered in short order....And if we're not sure, then we'll tell ya' where to go!

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Originally posted by ds1962:
Thanks, has 83000 miles on it and she just got it a month ago. Really doesn't do it when it's cold. I can bring these options up to carmax. They said to bring it back in if it did it again. It's done it three more times. I'll check out the forum.

Keep us posted. I have a friend at FCA that’s following this thread.

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Originally posted by PowerSurge:

quote:

Originally posted by Perception:

quote:

quote:
Originally posted by PowerSurge:
More than likely it’s a bad crankshaft position sensor. Those year model Jeeps are notorious for that. About 15 bucks on rockauto.com

It doesn't really sound like a cps to me, usually they just crank and won't start at all when one of those fails. I've replaced a number of them though, and none has ever set a code. Like everyone else said, they fail so frequently I always carry a spare with me. Buy OEM, the aftermarket ones are even worse.

Look it up on youtube, they are fairly easy to test. There are two different styles depending on year however, so make sure you are looking at the right test.

When they fail on those model year jeeps, the symptoms are exactly as he describes. Obviously it could be something else like a bad TIPM, but since it is not throwing a code I would go with the cps first.

Only had one fail on me, a GM 3800 engine. I worked in a GM dealership at that time. Engine shutdown at random times, no set pattern, only that the car was at normal operating temperatures, stall and start right back up. Until one day it stalled and would not start, normal crank. Cycled ignition switch on and off and on. Still no start. As I'm cranking it I look at the tachometer, no needle movement. Second crank attempt I'm looking at the tach, no needle movement, suddenly the needle moves, car fires up. Went back to work, we replaced the crank sensor, problem solved.

I had a Jetta that did that it ended up being a dying fuel pump.