Weird Fuel Pump Problem
I have a 2009 SR22 Turbo (TN) with a peculiar fuel flow issue. This issue can be replicated on the ground as well as in flight. Typical LOP cruise is at 30 inches MP, 2500 rpm, 17.5 gph. If I set this up with the fuel pump in low boost (POH calls for first 30 mins of cruise flight with pump on) when I turn the pump off the fuel flow goes UP to about 19gph. If I then reset the mixture to give 17.5 gph again and turn the pump on the fuel flow goes down about 1.5 gph. Switching tanks gives the same result, the pump makes the usual sound on the ground with the engine off and the observed fuel flow (engine off) looks as it's always done. High boost does what it should. Everything else engine wise seems normal.
Any help appreciated.
Thanks
Steve