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Oil pressure fluctuations

in 912 / 914 Technical Questions 6 years ago

  • Re: Oil pressure fluctuations

    by » 6 years ago

    Bill, sounds perfectly logical. The error mode is exactly as you describe. However, the independent sensor with Bluetooth-phone display doesn't show any fluctuations (see video). That's what we don't understand.

    EDIT: sorry, i probably broke the video links, here they are again:
    https://cloudstorage.uni-oldenburg.de/s/OsS987hCQ5dq7fE
    shows simultaneously
    -the rotax-sensor displayed at the Dynon, Setup 4 correct for Rotax sensor
    -an independent battery powered oil pressure sensor with Display via Bluetooth and mobile phone
    You may see the fluctuations in question only at the Dynon.

    https://cloudstorage.uni-oldenburg.de/s/kzop3IsLK3shzrJ
    shows simultaneously
    -the rotax-sensor displayed at the Dynon, Setup 5 (incorrect for Rotax sensor, correct for the Kavlico-sensor)
    -an independent battery powered oil pressure sensor with Display via Bluetooth and mobile phone
    You may see no fluctuations, but the values are way off (what is to be expected)
      
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  • Re: Oil pressure fluctuations

    by » 6 years ago

    I suspect that the Bluetooth sensor is highly dampened to produce a stable reading.
    The Dynon is also dampened to a lesser degree.
    The ultimate answer is to install a mechanical gauge at least temporarily to confirm the fluctuations.
    Check out the mechanical gauge in this video.

    https://youtu.be/e-oo_tASCRU

    It is now rock steady.

    https://youtu.be/j7XyLUs6e94

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
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  • Re: Oil pressure fluctuations

    by » 6 years ago

    Hi Bill,
    Gauges tend to be steady over a digital system due to the sample rate of the instrument and or its software..

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: Oil pressure fluctuations

    by » 6 years ago

    An update:

    Kavlico sensor, Dynon-Display
    https://cloudstorage.uni-oldenburg.de/s/9SnWCPDjxSSuCDr with fluctuations

    Kavlico sensor, analog instrument
    https://cloudstorage.uni-oldenburg.de/s/yK1wZiaqBsZh8op no fluctuations

    This appears to me to point to the Dynon EMS.

    What we checked:
    Rotax sensor, at the engine, voltage Pin 6-Ground: no fluctuations
    Rotax sensor, external air pressure, heated to 70°, Voltage Pin6-ground: no fluctuations
    Rotax sensor, external air pressure, heated to 70°, Voltage Pin6-external 12V: no fluctuations
    Kavlico sensor, external air pressure, heated to 70°, Voltage Pin6-ground: no fluctuations
    Kavlico sensor, external air pressure, heated to 70°, Voltage Pin6-external 12V: no fluctuations
    VDO sensor, at the engine, analog instrument: no fluctuations
    VDO sensor, at the engine, Dynon: values off (it's a 0-5bar type instead of the required 0-10 bar), little fluctuations
    Rotax-sensor, at the engine, setup for kavlico: values off, little fluctuations
    Bluetooth sensor, at the engine, mobile phone display: no fluctuations

    Fluctuations only appear when values are displayed at the Dynon. Fluctuations appear to be less when the displayed values are in the upper 20% of the range. Maybe someone from Dynon may relate this to the internal measurement setup/schematics of pin 6 input.

    The Dynon just came back from firmware update and Horizon calibration.
      
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  • Re: Oil pressure fluctuations

    by » 6 years ago

    Try bypassing the Dynon ground you have now and just try a temporary good ground. It needs to be ruled in or out.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report
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