Crank won't start

1996 F150, 5.0L 5-spd 4x4

Crank no start, ambient temp has no effect

Plug in the diagnostic scanner clear DTC’s it starts every time, starts for the rest of the day, runs smooth and strong, the next morning crank no start, repeat

Parts replaced-battery, solenoid, starter, 3-O2 sensors, dist. cap rotor plugs wires, crank shaft position sensor, coolant temp sensor, a/c components, coolant temp sending unit, fuel pressure regulator, ecm (yes it was programmed to the vin), fuel filter, egr solenoid.

Things checked-ground strap from rad support to frame, ground from frame to cab, ground from intake bracket to firewall, ground from battery to inside fender well, all fuses, fuel pressure, there is fire coming from top wire of ignition control module for pip in distributor, disconnect the battery over night has no effect.

Maybe reading the DTCs instead of just clearing them would be a better option.


And posting those DTCs here so we could help spend more of your money.

Shotgun spending to fix a problem rarely works as you have found out. Diagnosing the problem to find the failure is always the best path.


Continuing the discussion from Crank won't start:

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P0135 heater circuit error
P0141 heater circuit
P0155 heatr circuit error

Continuing the discussion from Crank won't start:

I should add after starting i used it for errands, around 8 starts even sat for a couple of hours and started right up. But tomorrow morning it won’t start till i clear DTCs. :crazy_face:

Considering that all 3 codes are CIRCUIT errors, all 3 occurred at the same time and is causing a crank-no-start condition, that tells me they are not O2 sensor problems. It would make me think it IS an ECU problem BUT… You changed the ECU, checked fuses and grounds already and still have the problem…

The list of causes for all 3 codes is this…

  • Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

I think the problem is with the wring harness and that you have a short to ground. You pretty much covered 4 of the 5 and that is what is left. A short to ground in a part of the harness that that runs WITH all 3 O2 sensors (that is a big hint!!) that is grounding out the ignition, or some other circuit that prevents start… check for spark and fuel when it fails to start as a direction…

That would explain the no-start problem where none of the codes would. You need a wiring diagram so you can see where the O2 sensor heater circuits run and then you need to chase the harness to find where it has chaffed through to cause a short. I suspect it lays on top of the bellhousing running on top of or alongside the transmission and the engine motion has rubbed through the wires.

This answer is more like a question. It sounds to me like the ECU is intentionally programmed to refuse to let the engine run when one or more of these codes is present, as a protection. If so, I would focus on what triggers the codes.
My Mazda 2300 has a heated circuit that is slow to heat on a cold day. I turn the key to ON, but not START for 10 seconds, and no code will be triggered.