Fuel flow issue

[sstearns2]

My fuel flow works well once it has settled down in cruise but it becomes erratic with a change is mixture or power setting before settling down to accurate indications. Also turning on the fuel pump will add a bit of fuel flow in flight and will add a lot on the ground.

The sensor is mounted horizontally which is not ideal from what I've read on here. Any ideas other than that?

Thanks,
Scott

 

[jaba-who]

I have had similar problems with mine over they years. It seems to be a common problem among other dynonavionics users in my area. basically most of us have stopped bothering to look at the fuel flow gauge.

Mine commonly reads high (by about 8 liters/hour) especially after climb or changes of power. Takes some to settle back to the correct reading. My sensor is the the flowscan type and I have read that the red cube is better.

I spent lots of time rerouting the fuel line so it follows all the rules about being sensor  placed with wires vertical, having straight sections before and after and slight rise in the line. All to no avail.

 

[jakej]

Hi John
The 'red cube' is much better, don't see the issues you mentioned - I don't see me using the Flowscan units again

Jake J

 

[dynonsupport]

Fuel flow issues are tough for some people to nail down, unfortunately. Some folks can do exactly the things the fuel flow manufacturers recommended you don't (sharp bends, sensor with the wrong direction up, etc), and they're fine. Others find that they can't get stable readings not matter what they do. Fundamentally, the Dynon EMS systems are counting pulses that the impellers inside those sensors generate, so there isn't a real way for it to mis-measure a voltage, etc. What is true is that liquid turbulence in pipes/hoses can be complicated and hard to predict, unfortunately.