914 fuel flow variation
in 912 / 914 Technical Questions
9 years ago
Our 914 is set up with two ff transducers. The monitor is a GRT EIS and EFIS. system plumbed per latest Rotax direction with check valves. The aircraft has flown since 2005 and has 560 hours.
We have always seen variations in fuel flow , often as much as 1 or 2 gph. But the average seems to work out to be close to actual amount used and about 5.5 gph.
On this trip to SNF it has been worse than that. There were times on this trip that the ff was indicating zero. And the amount used was significantly less than actual. However the engine runs fine and the power is fine. I did notice the man pressure vary from 29.5 to 28.5 and back.
I have cleaned the filters in the Piersburg pumps (done each year and always clear) and all other filters in the system. I usually run just one pump so will try both the next time the problem occurs. I have cleaned the ff transducers by back flushing them and examining for debris. Found some years ago. I have remounted the transducers and made sure the lines in and out have no sharp bends.
Does anyone have any ideas? The transducers (Floscan 201) are mounted to a surface in the engine compartment. Perhaps they should mounted so they can move a little to eliminate vibration? The wiring is unshielded. Perhaps the signal wire needs shielded?
Any suggestions appreciated.
Jim Butcher. N241BW. Europa XS
We have always seen variations in fuel flow , often as much as 1 or 2 gph. But the average seems to work out to be close to actual amount used and about 5.5 gph.
On this trip to SNF it has been worse than that. There were times on this trip that the ff was indicating zero. And the amount used was significantly less than actual. However the engine runs fine and the power is fine. I did notice the man pressure vary from 29.5 to 28.5 and back.
I have cleaned the filters in the Piersburg pumps (done each year and always clear) and all other filters in the system. I usually run just one pump so will try both the next time the problem occurs. I have cleaned the ff transducers by back flushing them and examining for debris. Found some years ago. I have remounted the transducers and made sure the lines in and out have no sharp bends.
Does anyone have any ideas? The transducers (Floscan 201) are mounted to a surface in the engine compartment. Perhaps they should mounted so they can move a little to eliminate vibration? The wiring is unshielded. Perhaps the signal wire needs shielded?
Any suggestions appreciated.
Jim Butcher. N241BW. Europa XS
