Stalling problems

The "stick" you are referring to is the tachometer which displays engine speed. The "1" is for 1,000 rpm. What is important is what it reads for the first few seconds when you start the engine. It should go to around 1,500 rpm, then drop right back down. That proves the idle speed motor is working.

It sounds like you have something else going on related to the stalling. A vacuum leak in a hose or engine gasket is a good possibility. The engine computer is not designed to work with leaks but will try to make adjustments in response to the results of those leaks, and that can cause symptoms similar to what you described.

A good course of action is to have a mechanic connect a scanner that can view and record live sensor data during a test drive. When the stalling or erratic idle occurs, the "record" button is pressed. The recorded sensor data can be reviewed frame-by-frame slowly at the shop to look for a glitch or signal dropout. Because that data passes through and is retained momentarily in the scanner's memory, the recording actually begins a few seconds before the record button is pressed so part of it will include when the stalling occurred.

Ernesto123, I am sorry my terminology does not agree with yours. I am using what we called it at the dealership and in the many Chrysler classes I attended.

If you are going to post that kind of reply, do not expect to be developing too many friendships on this site. It is a motor. It is a stepper motor, exactly the same as is used now for speedometers and other dash gauges. Stepper motors do not have brushes like regular motors, and they do not spin like regular motors. It is not a spring-loaded valve like you think. You are thinking of the troublesome Ford valve with two wires, a valve, and a spring. That thing runs on a varying voltage. This is a Chrysler product. There are four coils of wire tied to the four terminals in the connector. They are pulsed with varying duty cycle voltage signals and varying polarity to position the armature of the motor to various positions. Those positions are called "steps" and there are 256 of them. On my Chrysler DRB3 scanner, under live data, it lists "AIS steps:" to show how far the computer is commanding the valve to open. As the armature turns, it runs a threaded shaft in and out to open and close the valve. I had these apart to purposely break them and run hidden wires to switches to create real-life learning experiences for my students to troubleshoot. I played with stepper motors at the Chrysler Electrical classes. The trainers call them automatic idle speed motors so if it is good enough for them, it is good enough for you too. Different manufactures call their parts by different names. Do not be calling me ignorant just because you do not like the name I call something. GM uses the same part and has a different name for it too.

When you pull this motor out, there is nothing to clean on it. The carbon buildup, which has not been a problem in over ten years, is in the air passage around the throttle blade. I used to clean those at the dealership, but it was only a problem on the 3.0L engines. That does not mean it could not happen on other engines, but if you would have read the original problem, you would see the engine has been stalling while driving. You can pack that air passage full of mud, or weld it shut for all anyone cares, and it will not cause stalling while driving. Why in the world should we start off looking for some obscure VTSS problem that is so rare I never heard of it actually happening, or an AIS motor problem that does not fit the symptoms, when we already very likely know that this is caused by a very common problem. I gladly invite other people to add to my replies and I fully expect to be corrected when I make a mistake, but everyone else does that tactfully.

For you ernesto123, I invite you to take one of these motors, pull the little silver pin out of the side, pull the assembly apart, and find me a spring in it! Then explain why there are four terminals if it only has one coil of wire. Then count the individual coils in it. And if it is spring-loaded, why does the pintle valve stay in whatever position you place it in? And why does the new one move so darn hard when you tug on it or push it in? Maybe you think that new one needs to be cleaned too.

You are more than welcome to add to my posts, but you better be sure you understand how these systems work before you call me ignorant.

Regardless of what name we put on it, the photo you posted is the part that controls idle speed and there is a stepper motor inside it.

Welcome to the forum.

Caradiodoc

First of all, those diagnostic fault codes are to get you into the circuit with the problem, not to the specific part. Most mechanics would see the code for the crank sensor and replace it without doing further tests because ninety nine percent of the time they would be right and that would save you money for wasted diagnostic time. It is that one out of a hundred that are more involved and require further diagnosis. So do not fault the guys who just "throw a part at it". With a permanent problem such as a no-start condition, when the engine starts, you know you got it fixed. With an intermittent problem like you are having, you almost never know for certain if it is solved except if it acts up again, you know it is not fixed. I ran into the same problem very often when fixing TV's and VCR's. Intermittent problems drive us nuts.

As for the receipt for the computer from the first shop, that is not going to happen any more than Walmart will tell you what they paid for that new sweater you just bought. All parts are marked up above their cost so you pay an additional ten to twenty five percent. Contrary to the way democrats think, that profit is part of what keeps businesses in business. That markup is also what pays for the shipping, phone calls to the supplier, and the cost of doing it all a second time at no additional cost to you. Asking for the business to give you a copy of their invoice is like asking at a restaurant for a copy of their invoice for the food they bought. There is also a good chance the shop will not even get the bill until after the first of the month.

For warranty on your computer, the only thing anyone can expect you to supply is the receipt you got from the first shop that did the repair. It will list the part installed and the labor charge. The computer will typically have a serial number and/or a sticker with the re-builder's name and contact information. If there is a problem, they expect to be contacted by the shop that purchased the computer from them, but they also understand that a year later you might have moved across the country, or you could be on a trip, and it is not practical to go back to the same shop. That is why they keep records of the computers they rebuild. What you can expect is even if the second shop gets the computer replaced under warranty, you will have to pay the labor charge. They are going to have costs associated with contacting the computer supplier, shipping, labor to install it, and things like that. The first shop already charged you for those things and they had enough built into those charges to cover most future expenses related to that computer, so the first shop usually will not charge you again for that same repair.

Another way to look at it is say that Walmart sweater does not fit right and you want to exchange it. There will not be any cost doing that at Walmart, but you will not have much luck exchanging it at Sears.

Programming of the computer is not the issue. If your Jeep has the factory-installed anti-theft system, if either the engine computer or the body computer is replaced, it immediately learns that anti-theft programming from the other one. That does not need to be done by "re-flashing" it. That just means reinstalling the software. If your vehicle does not have the anti-theft system and the computer came programmed with it, the engine would not run. It would run for two seconds then quit.

The emissions system programming is irrelevant except to pass emissions testing. The wrong programming will not stop the engine from running. Using that logic, you could tow the vehicle across the state line, then it would magically run fine.

Now, addressing the sensors themselves, they are both fed the same supply voltage from the computer and they both share the same ground return wire. They each have their own signal wire. Any of those four wires could have an intermittent connection. Logic says the power and ground wires must be okay because the cam sensor is not setting a code. That just leaves the crank sensor's signal wire or the part of the computer that works with that signal. But there is another clinker to add to the story. When one of those signals is received, the computer knows it should be receiving the other signal too. Depending on how the loss of signal occurred, the computer may stop looking for the second signal when the first one goes away. It may not recognize that both signals are missing. That means there could be an intermittent connection in the power or ground wires for both sensors but only one sensor will set a fault code. That can be a real hard one to find. One clue that might lead to a wiring problem is that it seems to act up less when the vehicle is just sitting and idling. When it is moving, the engine will normally rock back and forth and tug on the wires. That is when connection problems will show up.

It sounds like you found a good mechanic you trust, but nothing you said suggests the first guy is not trying his best. I would let him continue to work on it a while longer, especially if he is willing to order another computer to try. If the problem persists with a second computer, since this is not a common problem to start with, that would really suggest the problem lies somewhere else. I can share two similar examples. If you go to a fancy restaurant and do not like the way your steak is prepared, you do not run down the street to a different restaurant and demand a different steak for free. Likewise, people tend to run from doctor to doctor trying to find the cure for their problem. If the first one does not figure it out right away, we go to the second one who will likely start over from the beginning with the same tests. Each new doctor starts over again from the beginning. If you have some really rare ailment, it could take a half dozen visits before they rule out the common stuff and start looking for the obscure things, but that will never happen if you keep switching to a different doctor. Mechanics are held to much higher standards than doctors. We call them incompetent if they do not know exactly what is wrong when we come through the door and especially if they do not figure it out on the first visit. Doctors only have to know two models in varying sizes. Mechanics have to learn hundreds of new models every year.

Jessiesjeep, now you see what your mechanic has to go through on that one out of a hundred that is not solved by simply replacing the sensor. My only comment is it is not necessary to disconnect the battery to perform the continuity tests. Most mechanics will do that when they are disconnecting the engine computer connectors repeatedly, but the sensor circuits are not powered up when the ignition switch is off.

The other problem is these tests are for an engine that will not run. There is a problem to be found. With an intermittent problem, you have to catch it while it is acting up, otherwise the defect will test fine. The same observations apply though when looking for a wire rubbed through or a corroded connection. One problem with cleaning connector terminals is you may solve the problem, but you will not know it. I have done this myself on my own cars, then you have to worry about it acting up again. It is always better if you can actually spot the problem so you can have confidence it is really fixed.

I really think caradiodoc is our best spokesperson, he taught this kind of stuff in school!

https://www.2carpros.com/questions/2006-ford-escape-twice-as-much-oil-in-car

https://www.2carpros.com/questions/1991-ford-f-150-hot-running-f150

And of course, my favorite section, this is the most recent, and I can and will, let this person , get the most out of this he can and I am offering even more if he wants it.

https://www.2carpros.com/questions/1979-jeep-cj7-front-disc-pads

Like I said, you came here for answers and opinions. I do not know computer cars well, I am learning and caradiodoc is an authority on it. here "my" thoughts on your "shut off and restart" I think it is barely running....that "Last" spark plug hit, brings it back to life....Sounds like IAC to me, but I am a CJ guy! Something else could cause this too? Cleaned this before? really? Did it get done right? How do you know? Maybe it is bad? anything "New", can be bad (a factor a lot of people overlook). These are just my opinions, I have seen the worst in folks.. Cell phones play a big part in actual, "full attention service", these days.

https://www.2carpros.com/questions/2005-ford-escape-rough-idle-at-low-rpm

Thought maybe, like me, you want it all, and must pick through it, and use what you can.

The Medic

Lots of new comments to respond to. Sorry that I gave the impression you did not trust your mechanic. I am visualizing someone who received less than ideal results after a single visit, and that is not your case.

Your idea of an intermittent problem is a matter of incorrect terminology between us. It is true the problem is always there, but being intermittent means it only acts up once in a while. As an example, a head light that never turns on has a definite problem that can be diagnosed by various means. When it does turn on, you know the problem is fixed. A head light that flickers off and on once every hour is an intermittent problem. If you pick the vehicle up from the shop and the head light is on, how do you know it is fixed? It could act up again in another hour, a day, or a month. No one knows if it is fixed unless something was found that made the problem show up. Most of the time that type of problem is solved by accidentally stumbling upon the cause. For example, if that head light comes on while the mechanic wiggles an electrical connector, then he takes it apart and sees a corroded connector pin, he will be pretty confident he found the problem. But, those terminals can also have a light film of corrosion that is real hard to see, and taking the connector apart and putting it back together can temporarily scratch a clean spot on them so they make good contact again for a little while. That might make that head light work fine for months, but the mechanic might have also cleaned a corroded ground wire. Now he thinks the ground wire was the problem, not realizing the connector terminal is still not making the best contact, and it is going to cause trouble again in a few weeks.

When anyone "tries" a dozen things to solve an intermittent problem, he might get lucky and one of them did, or he might have introduced a dozen new variables into the mix.

One thing that mechanics are really bad at is verbal communication. I found out very quickly while teaching how important correct grammar and terminology are, but using that terminology with customers can easily sound like we're talking down to them. As for, "his answer is something like 'run it until it gets worse cause I am not sure what is going on", I understand completely what he is thinking, but he did a lousy job of saying it. I ran into this very often when running service calls to fix TV's. Suppose the picture goes black for five minutes once a week. What am I supposed to do sitting behind the TV when the problem is not acting up? Everything is working correctly so there is no defect to be found. I would tell people to put up with it until it got worse so there was a chance I could catch it in the defective state and do some troubleshooting. Intermittent problems like that drove us nuts because you had to catch the problem in the act, and you were never sure if it was fixed.

As for the spacers on the crankshaft position sensor, that air gap they set is indeed rather critical. While replacing transmissions at the dealership, after the first half dozen, I got "smart" and figured out I did not need that spacer because I was just that good. I got lucky on the next half dozen when not using that spacer, but I heard through the grapevine that the thirteenth one developed a stalling problem two weeks after I worked on it and a different shop diagnosed and replaced that sensor. Now, it is entirely possible the sensor really did become heat-sensitive and fail after driving a while, but I suspect I caused that intermittent problem by not following proper procedure. Had that second shop known that, and the spacing was the only problem, the sensor would not have had to been replaced. It simply would have needed to be reinstalled with a new spacer. The only time the sensor would have to be replaced is if it was installed too far and hit the spinning flex plate and was broken.

Jessiesjeep, I do not think this spacing issue is related to your stalling problem because it sounds like it only stalls after prolonged idling. The classic way these sensors fail is when warm, and they work again after cooling down for an hour. The failing/stalling can happen while driving too, not just standing still. The other clue is when the signal is lost from that sensor, whether it fails when warm or the spacing is wrong, the engine computer will detect that, set a diagnostic fault code in memory, and turn on the check engine light. You mentioned previously that code 320 was set, and that is related to the crankshaft position sensor. The computer does not know why the signal stopped showing up, only that it did. While incorrect spacing could be the problem, as in that one that I suspect I caused, I think it is more likely the sensor itself is failing or there is a break in the wiring such as a corroded terminal in a connector. In very rare instances the engine computer could fail to recognize the signal, but to have a replacement computer do exactly the same thing is pretty unlikely.

Finally, CJ MEDEVAC, if you feel like thinking I am a genius, well you just go right ahead. That just proves I got another one fooled!