20 F150 5.0 OBD question

Discussion in '13th Generation F-Series : 2015 - Present' started by mchapmanjr70, Dec 28, 2021.

  1. mchapmanjr70

    mchapmanjr70 Junior Member

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    Hey guys,

    I’ve been an F150 owner form 30 years, and usually do my own work, but I came across something on my ‘20 5.0 that I’m having problems tracking down.

    I’ve been getting P0172 and P0175 errors for a couple months, indicating both banks are too rich. The engine is stock. I tried to reset it several times and let it relearn, but…

    I broke down and had the dealership run it down. All they were able to tell me after 4 hours was that it wasn’t the fuel pump, sending unit or EVAP canister/sensor. They said it had to be on the fuel rail.

    I took it home, searched the internet some more, then set a day and replaced the upper injectors, fuel rail pressure sensor, and MAP sensor. Then I set the PCM to relearn. Within 24 hours I was getting the same error codes.

    Any ideas of what I could be missing?

    Thanks in advance…

    Michael


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  2. MarkVietNamEraVET

    MarkVietNamEraVET Junior Member

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    Disconnect ground cable from battery & make sure it is away from negative post. Connect a jumper wire from positive post to disconnected negative cable & let it set for 3 minutes. This will enable your computer modules, sensors, etc. to clear completely. Let us know how it goes, thanks, Mark
     
  3. Roush PSD Interceptor

    Roush PSD Interceptor 7.3L Straight Piped Diesel

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    How long has it been since the MAF was cleaned?
    Clean the MAF with approved cleaner,
    follow directions.
     
  4. mchapmanjr70

    mchapmanjr70 Junior Member

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    The truck has 40k, mostly highway miles. Believe it or not, since I thought MAF sensor first, this truck does not have one.


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  5. Roush PSD Interceptor

    Roush PSD Interceptor 7.3L Straight Piped Diesel

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    @mchapmanjr70

    Pressure and Temperature. - MAP

    Since you already went over upper injectors, fuel rail pressure sensor, and MAP sensor.

    • Engine mechanical problems
    • Defective Oxygen Sensor
    • Defective Fuel Pressure Regulator <-------
    • Defective Coolant and/or Air Temperature Sensor
    • Thermostat is stuck open
    • Ignition Misfires
    • Defective Throttle Position Sensor
    • Defective or restricted fuel return line
    Were the other ticks to hit.

    Are you able to measure fuel pressure?
    Rent-a-tool ... You know which one without me calling out a name.
     

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