Stalling again

[Michael Carlin]

Truck has dies on four or five occasions. Usually at low rpm in a parking lot while I blipped the throttle to move it while seesawing into or out of a parking space.

Saturday night, 2300, driving across west 94 in St. Paul, ambient about 40 degrees fahrenheit, it just dies. One minute running fine, the next quits like the switch was turned off.

Pull over, my brother, who I am following pulls over. I crank it, turns over good, no start.

I get out with my good clothes on and open the bleed on the fuel filter. Ask my brother to check to see in I am getting fuel. Crank, he is screaming immediately that I have fuel "all over the place" so I surmise that the lift pump is working.

Still no start.

I leave the ignition in the run position and attempt to zero the codes by standing on brake and throttle simultaneously, hold it for thirty seconds. Still on trying, good crank no start.

Get out, unplug the Kennedy extension harness from the Kennedy supplied FSD, now mounted on the Kennedy supplied FSD cooler. Plug it back it in. It starts and has run about 250 miles with no problems.

I pulled the codes this evening. I get 12, 15, 19, 12. I zero them by standing on the brake and throttle simultaneously. Continuous 12s.

Now, 15 = Enigne Coolant Temp Sensor High (low Temp) and 19 = Crankshaft postion sensor fault. Yes? No?
What is up, I swear if I get the promotion on Thursday this truck is going to get traded unless I can figure out how to make it reliable. Oh it is a 94 with 171K on it has a new pump at about 92K and a new FSD at about 155K. I like JK, but I do not want to have to spend $275 for a new FSD every 20K.

Does anyone have any suggestions?
Oh I put in a new fuel filter about 5K ago, the one I replaced was nearly pristine.

[HowieE]

Hate to say it but I think you are about to buy another FSD. But this time as long as you have he extended harness mount the cooler and FSD somewhere forward of the radiator to insure it sees cool air.

I had the same problem and am on my third FSD even with the airhorn monted cooler. Mine is now mounted behind the bumper.

As for the truck starting after you disconnected the harness I think that was just coincedental with the FSD cooling down. But if the truck stalls again do the disconnect test first just to insure it is not a faulty connection. My truck would restart after about 30 seconds each time it stalled. Sounds like yours took longer so the connection amy have been the problem but tring the disconnection may help determine where the problem is.

[charliepeterson]

Try re-torqueing all the screws and nuts on the two drivers underneath as well as the four hold down screws onto the cool plate.

[gmctd]

Try unplugging and re-plugging all connectors in the engine harness. Sounds like intermittent connections.
Check all the wiring - battery, grounds, etc - in the engine bay, while you're at it.

And, as above, check the 1/4" nuts on the FSD driver transistors for looseness.
About 1/2 to 3/4 turn to snug them up.

[ucdavis]

@ 171K, wiring connections, particularly grounds, have seen lotsa vibration & (if exposed) corrosion potential. IIRC, the temp sensor is a thermistor, increasing resistance w/temp; infinite resistance (e.g. a bad ground) might set this code. I'd do a 100% check of grounds starting at batteries, engine compartment, then under dash & to PCM; clean & tighten each one, & if you are in a salted-road area, apply a no-ox grease like KopperShield.
Also, there are known problems w/the starter switch (located in column under ingnition key) in the early years. Some guys diagnose this by knocking the tilt wheel around after a stall & if that cures it, then switch is bad.
The advice on FSD given above is good, and quick/free, so try that as well.

[Michael Carlin]

Well I am going to have to drive this one for at least another year. This weekend I will be checking it over. Tuesday I drive up to bury my father in St. Cloud Minnesota. It has not misssed a beat since the stalling incident in St. Paul. I never did like St. Paul........... (being from Minneapolis when a kid) By the way, thanks guys!