Engine shuts off while driving without warning?

Hello,

I have checked for any recalls or Technical Service Bulletins for anything regarding this problem and didn't find anything. A problem like this could be caused by a wide variety of things, so all I can really do here is attempt to point you in the right direction and go from there. So this could be an intermittent problem with the Crankshaft Position Sensor(CKP) or the electrical connector or loose wires from the CKP to the Power-train Control Module(PCM) or "computer". In the diagrams down below I have included a description of the CKP sensor, a wiring diagram of the CKP circuit, the location of the ground wire for the RF shielding, and a guide for tracking down poor electrical connectors and intermittent problems in an automotive electrical circuit for you to go through. Please go through these guides and check the CKP circuit for an intermittent problem and get back to us with what you are able to find out. We can go from there.

Thanks,
Alex
2CarPros

Alex is absolutely correct, if I could add something from a clue that you gave us about the fuel cap light. On a rare occasion I have had the fuel tank pressure sensor short to vref which will cause the power-train control module to shut down. The vref circuit is a 5 volt circuit that several sensors use as a reference to for proper sensor voltage feedback. The fuel tank pressure sensor tells the power-train control module how much pressure is in the fuel tank, when the PCM tells the purge valve to open and pull a vacuum on the tank, the voltage will go from 2.65 to 1.50 approximately. And when the sensor fails, it usually fails high at 5 volts so now the PCM thinks that the fuel cap is off because the voltage is not coming down when a vacuum is commanded. Throttle position sensor, dpfe/egr sensor, fuel tank pressure sensor, are some of the most common vref short failures that I have seen. This is only one scenario, but if the vehicle will not start, probe the brown with white wire for 5 volts with the key on at any of those sensor connectors, or just unhook them in a no start condition to see if it starts. And if you have a scan tool that can look at the sensor readings, the ftp should read 2.65v with the key on engine off.

Hello again,

This type of failure should throw a Direct rouble Code(DTC), but not always. If you have a code reader it should be fairly straight forward on pulling the codes. Here is a link explaining how to do that:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If you don't have access to a code reader than you can go to your local auto parts store, like AutoZone and they will read them for free. Please get back to us with what the codes are and we can go from there.

Thanks,
Alex
2CarPros

Hello again,

The Malfunction Indicator Lamp(MIL) or "check engine" lamp is illuminated when a Direct Trouble Code(DTC) is set. It will be flashing when a catalyst damaging DTC is set. When you turn the ignition key to "RUN" the MIL should light up, and if there are no DTC(s) set, turn off. This is known as a bulb check to make sure the bulb is working. So if the MIL is not illuminated then there is no DTC set.

Thanks,
Alex
2CarPros

Bad alternator diodes can induce noise in the system and corrupt the crank sensor signal. Have replaced tons of alternators for this at my dealership, most of the time with no codes present or a code in continuous memory with no light on.

Hello,

Actually, yes it does. Hat old adage you get what you pay for. It is as true today is it has ever been. I would stick to Motorcraft (Ford), Delco, Denso, Bosch, or manufacturers of this caliber for replacement parts. There is a reason that vehicle manufacturers sub contract to companies like these for parts such as OEM fuel injectors, O2 sensors, and others. BM Double is very knowledgeable when it comes to the Ford Brand so you might want to check into this and get back to us with what you find out, please.

Thanks,
Alex
2CarPros

Yes sir, Motorcraft seems to be the best choice for alternators and not just because I'm a Ford guy, but because I've had to remove literally hundreds of customers' aftermarket alternators (brand new) because they did not work correctly.

Re-manufactured is good.

Awesome! Youa re welcome!

Excellent!