My fuel flow occasionally decides to read higher than it really is, then returns to normal some minutes/hours later.
Typical situation: I am flying in the cruise, lean of peak, and at some moment [for no apparent reason] the fuel flow increases by maybe 15%. I know this isn't reality, because the engine power output doesn't change - which it would do when running LOP and increasing fuel flow; there is no fuel leak visible (no dye stains visible on the lines or in the belly), and finally to clinch it - if I turn on the fuel boost pump (which is downstream from the transducer) then the flow reading goes back to what is was before the anomaly occurred, and remains normal for as long as the boost pump remains on. If I switch the pump off it starts telling lies again. The problem started after maybe 150hrs and has been recurring occasionally for 65hrs now.
Does anyone know what causes this kind of poor reading?
I have developed a few theories, but I won't bias your thinking with them.
IO-540, Bendix injection, Dynon D100 and D120, EI FT-60 RED CUBE installed after the gascolator and filter, but before the two fuel pumps, in a straight, roughly horisontal fuel line running slightly uphill. I realise I could move the transducer to get a better reading after the fuel servo. That is a fairly large job, and remember I had no problems with my install for 150hrs prior. I have not removed the transducer to perform an internal inspection.
Typical situation: I am flying in the cruise, lean of peak, and at some moment [for no apparent reason] the fuel flow increases by maybe 15%. I know this isn't reality, because the engine power output doesn't change - which it would do when running LOP and increasing fuel flow; there is no fuel leak visible (no dye stains visible on the lines or in the belly), and finally to clinch it - if I turn on the fuel boost pump (which is downstream from the transducer) then the flow reading goes back to what is was before the anomaly occurred, and remains normal for as long as the boost pump remains on. If I switch the pump off it starts telling lies again. The problem started after maybe 150hrs and has been recurring occasionally for 65hrs now.
Does anyone know what causes this kind of poor reading?
I have developed a few theories, but I won't bias your thinking with them.
IO-540, Bendix injection, Dynon D100 and D120, EI FT-60 RED CUBE installed after the gascolator and filter, but before the two fuel pumps, in a straight, roughly horisontal fuel line running slightly uphill. I realise I could move the transducer to get a better reading after the fuel servo. That is a fairly large job, and remember I had no problems with my install for 150hrs prior. I have not removed the transducer to perform an internal inspection.
