Hey guys, I've got a 2010 F150 5.4L 3v that I've troubleshot pretty far and I'm running out of ideas. Drove a few hours on the Interstate, pulled off on an exit, truck stumbled then died. Now I get crank with no start (no sputter, no ignition fire of any kind) and no DTC codes, no check engine light (as far as I can tell, I'm not familiar enough with this truck to 100% confidently understand the sequence of the dummy lights in the non-running state.). Here is what I've tried:

Fuel System

• Replaced FPDM, no change.
• Checked applicable fuses, swapped applicable relays with other relays, swapped the fuel pump diode with the other diode, no change.
• Tested fuel pressure at fuel rail, 60PSI+ (maxed the gauged out)
• Poured 1/4oz of fuel directly into the manifold and attempted start, no change. (I know this is a bad idea -- I'm kind of desperate)

Ignition System

• Swapped PCM relay, no change.
• Checked all PCM fuses, none burned out.
• Replaced crank position sensor, no change.
• Borescope into cam position sensor and crank position sensor ports, things look intact -- didn't see any plastic pieces from a broken guide. Timing chains spin as expected on starter. Crank position toothed wheel appears to be intact.
• Attempted to start with the crank position sensor electrically disconnected, computer did not throw a DTC code.

I don't think it's fuel related as there is 60PSI at the fuel rail. I don't think it's a timing failure because it seems it would still fire and sputter. I don't think it's the crank position sensor as I've swapped it for a new one.

This truck had the notorious timing chain rattle/phaser rattle, which I have since learned is a pretty bad indictor of pending failure -- this is my father-in-law's truck that I borrowed. I'm down to swapping out the PCM -- especially since it did not throw a code when I attempted to start it with the crank position sensor disconnected. However, it sounds like PCM failures are quite rare. Just want to get some sound boarding here to check my own sanity.

 

I would do a compression test.

 

My 2009 did the same thing 2 years ago (with same engine) and replacing the crank position sensor located behind the air compressor fixed it. I also had to replace the connector at same time, the original one was bad. Truck fired right up after that.

I also read somewhere that the wire can ground out, so testing your leads may be a good thing to do. While this video isn’t a Ford specific tutorial, it is good information to test your sensor and connectors for signal/continuity.