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Hi everyone,

Was flying my Sling 4 a week or so back and noticed my MAP reading 0.0 - not sure exactly WHEN this happened, but it was certainly during flight as runups and takeoff were definately reading normal pressures.  I was operating at around 50-60% throttle at the time in a slow cruise, dodging cloud and a little bumpy - increasing to 100% got the MAP up to about 5.0 before it fell again back to 0.0.  I didn't notice any drop in power, but then I did return to land pretty much straight away and have not flown since, so not sure if I will have full power....  

After landing and shutting down, the MAP jumped immediately back to atmospheric pressure (around 29). 

I suspect a loose or broken sense wire to the sensor, but would this be a plausible explaination for this behaviour?  From what I understand there is a seperate static pressure sensor feeding into the system, so with the engine off the ambient pressure is being indicated rather than the MAP, which is referenced from zero?

I'm hoping to spend some time this weekend checking the wiring to the MAP sensor - I have a gut feeing I know where a loose connection may be, but curious as to what (if any) effect a bad reading would have on the TCU and engine operation...

 

  • Re: 914 MAP reading zero

    by » 3 years ago


    Where is your MAP Gauge getting its sender information from?
    It is unlikely to be the same sender that the Turbo uses.
    The Engine was fine; Your instrumentation was the only problem.


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


  • Re: 914 MAP reading zero

    by » 3 years ago


    I believe its the sensor that is on the T between the two manifolds, which from my understanding goes to the ECU and then onwards to the Garmin gear (G3X) - I thought this was the only MAP sensor in the system?   My aircraft is pre-owned so I didn't have anything to do with the build/install, tracing it out as I go ?.   I did find one wire for the MAP has come out of a plug (departed from the pin) - this is what I aim to fix on the weekend (in between work and bad weather) - hopefully this is the only issue....

     

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  • Re: 914 MAP reading zero

    by » 3 years ago


    First you need to determine whether or not you have lost power. Observing propeller rpm on full throttle runup should answer that question. If you have lost power, check that the carb sockets have not pulled away, creating an air leak. If you have not lost power, run down the instrumentation issue.

     


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