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Fuel Flow sensor Install

in General Tech Discussion 6 years ago

  • Re: Fuel Flow sensor Install

    by » 5 years ago

    You have a pump that can deliver 30 gph unrestricted.
    YOUR Return Line is dumping 4.7gph.
    At idle the engine will use about 0.5gph
    At WOT the engine will use about 5gph.

    Without taking the return flow into account...
    Your idle reading will be Off by ≈900%
    Your WOT reading will be Off by ≈200%

    You already reported that the display was showing 6.9gph at 2000rpm, on an engine that should actually burn about 0.5gph at idle. 6.9/0.5 = 1380% ;
    And showing 11gph at 5200rpm, on an engine that actually burns about 5gph at 5800 rpm. 11/5 = 220%.

    Is that close enough???
    - - - - -

    I just had another thought...
    The injector pressure regulator is commonly a Bypass Regulator.
    It should be bypassing about 20gph with One Fuel pump ON and about 30gph with BOTH pumps ON.
    Your return Flow should be in the 20-30gph range, NOT 4.7

    This might indicate that the Return Flow meter is located in the wrong return hose.
    There are two return lines that need to joint together BEFORE the Flow Meter.
    The Flow Meter should be located AFTER the Input Bypass Hose AND the Regulator Bypass hose come back together.

    It is time for a complete set of photos of this installation or you will need someone locally that understands the system to put eyes on it.

    We know SOMETHING is incorrect and YOU are not the person to be looking at it because you are too familiar with it and will only see what you expect to see.

    This is NOT a dispersion on you, it is human nature.
    This why in critical construction, One person does the work, and another person does the inspection.
    You should never inspect your own work.

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

    Thank you said by: Robert Hannigan
      
    Report

  • Re: Fuel Flow sensor Install

    by » 5 years ago

    jiott --

    Which fuel flow gauge do you use with your Red Cube sensor?


    Jiott is using only one sensor and displays total flow only, ignoring the return flow.
    - - -
    Robert, Your problem is NOT the Gauge, it is the installation.
    - - -

    We are still waiting for the results with each sender unplugged.
    Are you able to unplug and swap the senders before the Circular Connector, or are the senders hard pinned to the connector?
    That would be an excellent troubleshooting feature.!!!

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

      
    Report

  • Re: Fuel Flow sensor Install

    by » 5 years ago

    Bill I will try to check the flow back to the header but do you have and suggestion on I can use to test the flow.
      
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  • Re: Fuel Flow sensor Install

    by » 5 years ago

    Bill I have pictures of the install that I sent to the factory that I can send you. I have an AI coming to look at on the 24th.
      
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  • Re: Fuel Flow sensor Install

    by » 5 years ago

    You have everything you need to test the system already.
    The ideal configuration would be to have Connectors on the senders between the Senders and the Circular connector.

    This would make it possible/convenient to swap the senders.
    By connecting each sender individually to the FEED Transducer input of the FFDM you would be able to monitor what each sender is seeing.

    I am happy to help you but I can not tell what you have without the data and the pictures.

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

    Thank you said by: Robert Hannigan
      
    Report
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