Shuts off while driving, then good after waiting

Tiny
HIPHOPGUY
  • MEMBER
  • 1995 FORD TAURUS
  • AUTOMATIC
  • 160,000 MILES
I already replaced the fuel pump and the throttle position sensor and spark plugs. My car has no issue starting, and runs well while it's running, however, it will unexpectedly shut off while driving down the road, or while idling, the car still has power, the lights, and radio will stay on, but the check engine light will come on, and it's as if the car was just turned off while driving.

once the car shuts off, it will not start up again, it will crank but not turn over, as if the fuel pump is not working. However if you wait, half an hour (actually anywhere between 10 minutes and an hour, but usually a half hour) it will start back up as if nothing was wrong and I am able to drive it again normally.

i have found that the problem happens much faster when I hit red lights and have to idle, so anytime I hit a red light for an extended period of time, I can turn off the car and turn it back on and it will prolong the car shutting off on it's own, as long as I am able to turn the car off before it turns itself off, it usually starts back up fine.

to make matters even more confusing, I live in Colorado Springs about an hour and half from Denver, if I hit the highway, and there are no red lights, or traffic, I am able to drive the vehicle all the way to Denver (over 100 miles) without any issues.

i am stumped, if anyone has similar issues, or ideas as to why I am always able to start the car after waiting for an extended period of time, please let me know.
Saturday, December 21st, 2019 AT 4:04 PM

14 Replies

Tiny
KASEKENNY
  • MECHANIC
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This sounds like a crankshaft position sensor. However, your vehicle doesn't have a traditional sensor. It has what is called a hall effect vane switch. This is still susceptible to the same issue because the hall effect sensors are all the same construction. When they begin to fail and exposed to heat from the engine or the environment, they actually open and don't send a signal any more. The PCM then thinks the engine was shut off and it just stops sending a signal for the spark and the engine shuts off. Everything else stays on because the key is still in the on position but the engine just cuts off.

Here is a guide that gives more detail:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

I then attached the detail about your vehicle and the procedure to replace this. Based on my experience and what you are describing I would replace then and then retest it.
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Sunday, December 22nd, 2019 AT 3:35 PM
Tiny
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Thank you for the quick response, so from the diagrams, my understanding is that the 'hall effect vane switch' is inside the distributor and cannot be replaced without replacing the entire distributor assembly? Is that correct? If so I will purchase a distributor and replace it and then test to see if it fixed the problem.
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Monday, December 23rd, 2019 AT 4:53 PM
Tiny
KASEKENNY
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That is correct. You can replace it but the assembly is probably easier and not that much more expensive. Plus, you need a press to do it right and not many people have one.
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Monday, December 23rd, 2019 AT 6:28 PM
Tiny
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So the person who was installing the distributor did not install it properly and now my car will not start, is there a way for me to "reset" the timing so I can reinstall the new distributor assembly?
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Thursday, January 2nd, 2020 AT 2:11 PM
Tiny
KASEKENNY
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If it was not installed properly then you need to either check the timing to make sure it is not correct. However, if it is not starting then that is pretty clear. The only way is to remove it and reinstall it. I attached the procedures on how to do this.
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Thursday, January 2nd, 2020 AT 6:04 PM
Tiny
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Okay, I got the distributor assembly out, and got it back in, and now the car started and ran, and it ran perfect for 3 days with no issues. I even drove it to Denver and back during those 3 days without turning off the vehicle at any lights.

Then the original issue started again, where I will be driving and the vehicle will just cut off, except now it happens if I drive a mile or less, and I can't idle for more than a few minutes or it happens again. Any ideas?
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Friday, January 10th, 2020 AT 2:49 PM
Tiny
KASEKENNY
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Does the engine start back up immediately? Can you give it a little gas when it starts to stall to keep it running?
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Friday, January 10th, 2020 AT 5:38 PM
Tiny
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The engine does not start back up immediately. If I drive for a mile and it cuts off, it takes more like an hour or two hours before I am able to start the vehicle again, if the vehicle is started and does not stay on, then it takes another 2 hours to get it running again.

It is cutting off while driving, so it is while I am accelerating, I stall and am unable to use the gas to keep it running because it cuts off regardless.

The hall vane switch is brand new because the distributor assembly is new.
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Saturday, January 11th, 2020 AT 7:55 PM
Tiny
CARADIODOC
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Hi guys. Sounds like you replaced the camshaft position sensor, which is in the distributor. An equally-good suspect is the crankshaft position sensor. KASEKENNY1 is right about the heat problem. This commonly happens when a hot engine is stopped for a short time, as in when stopping for gas. That is "hot soak", and it allows time for engine heat to migrate up to the sensors. It can happen too just while driving, but that is less common. When driving at sustained highway speeds, as you've noticed, natural air flow keeps the sensors cool. When one does fail, it takes up to about an hour for them to cool down, then they work again. This type of failure can go on for some time, but eventually it will be permanent.

One thing that wasn't mentioned yet was having the diagnostic fault codes read and recorded. Be aware fault codes never say to replace a part or that one is defective. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it is actually the cause of that code about half of the time. Normally we have to look for wiring and connector terminal problems first, and mechanical problems associated with that part, but in this case, given the heat-related nature of the problem, the sensors themselves are the best suspects.

The people at most auto parts stores will read the fault codes for you for free.
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Sunday, January 12th, 2020 AT 12:59 PM
Tiny
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I was told this car does not have a "crankshaft" sensor, it has a "hall vane effect switch" instead, and it is inside the distributor assembly, so the reason I replaced the entire assembly was to replace the "crankshaft/hall vane switch". Are you saying the "cam shaft sensor" could be the culprit if I have not replaced that already?

I have already replaced the fuel pump, throttle position sensor, spark plugs, and now the entire distributor assembly.
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Sunday, January 12th, 2020 AT 1:38 PM
Tiny
CARADIODOC
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It's the camshaft position sensor that is inside the distributor. It's easy to remember because the distributor is turned by a gear on the camshaft.

There's four different engines that were available in your model. I guessed at the 3.0L single-camshaft engine. That one uses the crankshaft position sensor shown in this photo. As its name implies, it generates its signal by reading notches or holes, on something attached to the crankshaft. The same sensor is used on the dual camshaft 3.0L engine.

If you have the 3.2L or 3.8L engine, there is no separate crankshaft position sensor shown on the diagrams or in the parts listings, but in case you, (we) aren't confused enough already, the second drawing shows the location of the crank sensor behind the vibration damper, and they show that illustration under every engine size with no mention if it only pertains to some of them. This is probably why KASEKENNY1 never mentioned it.

Sorry to add to the confusion, but this seemed to be the most likely suspect once the new distributor didn't solve the problem.
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Sunday, January 12th, 2020 AT 2:37 PM
Tiny
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1995 Ford Taurus 6 Cylinders U 3.0L MFI OHV

is my specs by VIN. Because more information typically means a better diagnoses. Does the instructions you gave apply to this make and model?
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Sunday, January 12th, 2020 AT 3:01 PM
Tiny
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Also if it was the "crank sensor" is there a reason that replacing the distributor assembly allowed the car to work flawlessly for 3 days before going back to the original problem? I was able to drive several hundred miles, without turning off the car at lights, and I was able to idle for an hour plus without any issues, for several days. Then it went back to not working, but shuts off much faster than before I replaced the distributor.
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Sunday, January 12th, 2020 AT 3:08 PM
Tiny
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For my first comment, this may sound sarcastic, but believe me, it is not meant that way. You filled up with gas at a different station, and their gas has a different formulation of additives. You were driving during the day when the sun was out, and the stalling only occurs at night or on cloudy days. You made fewer right-hand turns per hour, so less stalling occurred.

That was somewhat of an inside joke to imply there are a lot of variables that could have contributed to the problem, and we often see some that have no bearing on it at all, and we often overlook things that would have made great clues. The truth is there are things that could have prevented the stalling from occurring that we haven't considered. Outside air temperature is one of them. Since heat is a common factor for this problem on all car brands, it stands to reason this type of failure will occur more often in summer and less often on cold winter days. Driving in rain or snow can affect it too. Water splashing onto the sensor will keep it cool, so it fails less often, or, if the seal is damaged in the connector, water sneaking in can adversely affect the connection made by a pair of mating terminals, and make the problem occur more often.

The one that comes to my mind right away is those mating terminals in a connector. We used to see this all the time with tvs. You walk across the floor and the picture flashes bright and dim. I get there, unplug one circuit board, look at it, scratch my head, plug it back in, and the problem is solved, . . . for a few weeks, then it comes back.

In tvs and in cars, there can be a light film of corrosion that builds up on those terminals. Eventually the poor contact causes a symptom or problem. When the part is unplugged, there is a scratching action to those terminals that scrapes off some of that corrosion and leaves a nice, clean, shiny spot that makes a good connection, at least until that corrosion migrates back and the problem comes back.

Besides replacing the wrong part, there's two things that can keep the problem occurring even after the correct part was replaced. The first has to do again with those connector terminals. Often an uninformed do-it-yourselfer or mechanic sticks a test probe into a terminal to take a reading, and the probe is fat enough to spread the terminal open too much. Now it won't make solid contact with its mate in the other half of the connector. That can even occur over time all by itself. This leads to the second problem.

That second problem is common among competent do-it-yourselfers. It has to do with the diagnostic fault codes, which, by the way, I haven't seen any mention of yet for your car. That should have been the starting point to this diagnosis, but too many people think those fault codes tell you which part to replace. In fact, they never do on any car brand or model. Fault codes tell you the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a sensor or other part is referenced in a fault code, that part is actually the cause of that code only about half of the time. First we have to rule out wiring problems, and, . . . and, . . . and those connector terminal problems. We also have to consider mechanical problems associated with that part. In this case, some crankshaft position sensors on some engines have very critical air gaps with simple methods of adjusting them, as long as you're aware of the need to do that. That's one example of a mechanical problem with the part. Everything can be working perfectly, but if you increase that air gap, the engine may not run or it could stall intermittently.

To boil down all this wondrous information, my first guess is the wrong sensor was replaced and it's just coincidence the engine didn't stall for three days. My second guess it wasn't really the camshaft sensor that failed. It was an intermittent connection in its connector that did it. I'm less likely to believe myself on that connector issue because those are not normally associated with heat or temperature.

There is also a potential problem with replacing more random parts before anything is actually diagnosed. We don't want to add more variables to the problem. Before you do anything else, I would have the diagnostic fault codes read and recorded. You can go here:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

to see how to do it yourself, but it may be faster to have them read at an auto parts store. The people there will do that for you for free, but most of them can only do that on the more-advanced and standardized 1996 and newer models. For a '95, you might have to visit a repair shop.

You can see the list of fault codes here too, or we can interpret them for you. The next problem is code 14 is the only one that refers to loss of a timing signal. Ford didn't use separate codes for the different sensors. Given the symptoms you've described so far, there's little value to this fault code, which is likely why KASEKENNY1 never brought it up. On '96 and newer models, well over 2,000 defects can be detected, and the fault codes get a real lot more specific.

On your engine, the engineers put the camshaft position sensor and the crankshaft position sensor in places where they're uncommonly difficult to replace, so you have to decide which is the better way to proceed. Since there is no dedicated diagnostic fault code assigned to the crankshaft position sensor, you could decide to replace it as a test, but that requires removing the vibration damper from the front of the crankshaft. That is rather time-consuming. You might decide instead a better investment would be to have a mechanic take the car on a test-drive with a scanner connected that has "record" capabilities. Most of them do. With that, you press the "record" button when the problem occurs, but in this case you have to do that before the engine stops rotating. If this occurs while driving at highway speed, that could give you a good five seconds or more. If you're sitting idling at a red light, the engine will stop rotating long before you can press the "record" button. Even if you press it right away, the engine has stopped, so it would be normal for the signals to stop showing up from both sensors, so there's be nothing of value to see.

Since the engine data passes through the scanner's memory, the recording actually begins a couple of seconds before you pressed the button. Later, you can replay that data slowly and see what changed or which signal dropped out when the stalling occurred. This is especially useful when no fault code has set, which sometimes happens. A lot of mechanics have special scanners with limited capabilities that are designed just for this purpose. They often call them "flight recorders". Some will even send you on your way with it, then have you come back days later after the event has been recorded. This is useful when you have an intermittent problem that acts up perhaps only once every few days, and it isn't practical for the mechanic to mindlessly driving the car for hours on end.
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Monday, January 13th, 2020 AT 2:59 PM

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