Fuel Flow Transducer

[m188220]

I purchased and installed the FlightDEK-D180, wiring harnes, and Rotax engine monitoring kit. I was unable to start the engine and found the fuel flow transducer was not allowing any gas through.

The aircraft is a high wing CH701, and the transducer is installed between a Facet electric pump and the Rotax mechanical pump. It is using the Black/Yellow/Red twisted triple from the EMS harness. The K-value was set per the installation manual.

I removed the transducer and was then able to proceed with first start of the engine.

I later found that I was unable to blow air through the transducer with the power off--I haven't tried this with power on.

Should the transducer restrict gas flow with power off??? This doesn't sound safe.

Thanks,
Jeff

 

[dynonsupport]

That's distressing. There is NOTHING about the electical connection that can possibly restrict fuel flow. Mechanically, the flow sensor is a tunnel with an impeller that is designed such that even if the impeller is completely stopped up, fuel still flows with minimal pressure drop.

Additionally, ever fuel flow sensor is tested and calibrated by the manufacturer, yielding the K-factor number on the tag.

If you have a complete blockage, you're likely looking at some foreign object debris contamination.

 

[m188220]

I removed the gas lines and brass fittings from the fuel flow transducer and noticed a brown "plug" in the input orifice. This turned out to be dirt.

Turns out a one quarter inch hose is the perfect size for a wasp nest. While I was fitting the wings, I remember leaving the gas line disconnected for several days--the transducer is over six feet away and through the fuel selector valve!

Cleared the dirt and flushed it out, and it now works ok.

Thanks for your help.