Car shuts off after about 20 mins of running

MPD496,

Well, you've replaced every part of your ignition system except the one that is causing your problem.

It’s the PIP module in your distributor. That stands for Profile Ignition Pickup module. It’s also called a Hall Effect sensor, because that’s the name of the solid state device that makes the PIP work. And, the Ford parts books call it the distributor Stator, because it’s the part that doesn’t move. The rotor (a round disk with a window cut in it for each of the eight cylinders in the engine) spins through it.

It is the equivalent to a crank sensor on a Ford modular 4.6 liter V8. Because our cars still have distributors on them this sensor must be in the distributor, not on the crankshaft.

When each window passes the Hall Effect sensor in the PIP module, the permanent magnet in the PIP module causes a voltage to flow through the Hall Effect sensor. That voltage is read by the PCM (the EEC-IV main computer) and tells it exactly when each cylinder is at base timing (e.g. 10 degrees BTDC). Armed with that info, the PCM can tell the TFI Ignition module to switch the ignition coil to fire each spark plug at the right time.

The problem with Hall Effect sensors is that they are extremely temperature sensitive devices. In extreme duty environments like sitting on top of a car engine, the cylinder heads of which typically get to around 230 to 240 degrees F, the sensors require sophisticated temperature compensation circuitry to provide a constant (and accurate) signal over a temperature range from about -40 degrees to +240 degrees F. Since they have an analog output (that looks like a sine wave), they also require clipping circuitry to make the analog signal look like a nice clean digital (ON or OFF) signal to the PCM.

It does get worse over time, and it’s really not safe to have your car die on you in the middle of traffic! After just a couple of weeks mine was crapping out at least 3 or 4 times a day just like you reached over and turned off the key. Really not safe! The thing is temperature sensitive, so once it starts to degrade it will just continue to get worse.

The part only costs about $50.00 at the Ford dealer. The bummer is that the distributor has to be removed from the car to install the thing! The sensor portion slips over the center shaft of the distributor, so the drive gear has to be removed from the bottom of the distributor to install it.

Replace your PIP module, and you’re good to go!

In your case, if you get your new MSD distributor, that will do it as well.

A+ MLC

+2 PIP

yeah MLC is right on. excellent info too. i would just replace it with the MSD and call it a day.

mine did the same thing a couple years back, and with the same symptoms I replaced the stator that was the fix like they said above.

For future diagnostics: If there is also no injector pulsing (when the car acts up and there's no spark), the PIP is the place to look.

Had you still had injector pulsing but no spark, then the TFI, coil and other ignition components would have been the appropriate items to have bench tested or replaced.

Good luck.