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Toyota (2ZR-FXE) P0171

Discussion in 'Gen 3 Prius Main Forum' started by Jarmo, Feb 13, 2023.

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  1. Jarmo

    Jarmo Junior Member

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    Hello from Finland,
    I have Toyota Auris Hybrid (Engine 2ZR-FXE), and mileage is around 360000km.
    EGR system and manifold cleaned up 2 years ago.
    Now I have received the fault code P0171 few times.
    I have cleaned MAF sensor Twice and it have not been dirty at all.
    I have used TOAD-Scan software to determine problem.
    Mass air flow rate are
    0.17g/s at 0 RPM
    7.4 g/s at 1300RPM

    I think that problem is long term fuel trim - Bank 1 (LTFT)... It's all the time between +25% - +35%?
    When I accelerate both LTFT and STFT rises up so i think that it is not suction leak?
    Any ideas?

    -Jarmo
     
    #1 Jarmo, Feb 13, 2023
  2. ChapmanF

    ChapmanF Senior Member

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    P0171, a lean mixture, means either too much air is getting in or not enough fuel is being injected. The high LTFT shos the ECM is going as far as it can to increase the amount of fuel injected.

    It sounds as if you have been focused more on the too-much-air possibility (though I cannot quite tell if you have directly investigated for air leaks, or only drawn conclusions about them from changes in fuel-trim numbers). Have you investigated the fuel pressure or fuel injectors yet?
     
    #2 ChapmanF, Feb 13, 2023
  3. Jarmo

    Jarmo Junior Member

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    Thanks,
    Maybe it does not get fuel enough... I don't have test device for fuel pressure or fuel injectors yet.
    One posibility could be fuel filter, but It located inside of fuel tank I think?
    Is it possible add pressure meter for fuel line some place?
     
    #3 Jarmo, Feb 13, 2023
  4. Jarmo

    Jarmo Junior Member

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    Freeze data
     

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    #4 Jarmo, Feb 18, 2023
  5. Jarmo

    Jarmo Junior Member

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    I checked the fuel pressure. It was 26 psi only, so fuel pump assy will be next on the list. Fuel pump resistance was 7.9 ohm measured from top of tank connector. 17E25009-AE51-47F1-AFF4-35514B887BDE.jpeg 4D2C2353-3CB6-42F2-B248-AFAAD908BFFF.jpeg
     

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    #5 Jarmo, Mar 2, 2023
  6. Jarmo

    Jarmo Junior Member

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    "New" used fuel pump assy installed and now car works... So problem solved :) Now fuel pressure is around 46psi.
     
    #6 Jarmo, Mar 8, 2023
    Mr. F likes this.
  7. mke039

    mke039 Junior Member

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    Same problem. How did you T into the fuel system to get pressure?
     
    #7 mke039, Oct 26, 2023
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