REFLECTOR: FUEL PRESSURE PUZZLE

[Ron Brown]

Tom,

You're right - that doesn't make sense.  

Make sure the fuel pressure sensor is not mounted on the engine or otherwise picking up engine vibration.

This sensor should be mounted on the firewall and be fed from a fitting off the discharge of engine's mechanical fuel pump.  There should be a restriction (small orifice - 1/16" or smaller) which should dampen any pulses to the fuel pressure sensor as well as limit fuel flow if the sensor or its line ruptures.

Has it been acting this way ever since you started flying it or did this just start happening?

Ronnie  


  ----- Original Message ----- 
  From: Tom Martino 
  To: reflector at tvbf.org 
  Sent: Saturday, August 26, 2006 2:17 AM
  Subject: REFLECTOR: FUEL PRESSURE PUZZLE


   
  Something is happening that I can't figure out.   My engine (IO-540) runs great . but the fuel pressure reading (EFIS One w/ resistive sender) goes down as I increase power.  In fact, at 2700 RPM . fuel pressure reads "0".  Obviously, I was getting pressure because the engine was running perfectly, but the reading was zero.

   As I decrease power, the fuel pressure goes back up to normal (28 - 30).

  I thought it was simply an instrument error . BUT . when I turn on the "boost" pump . during the low readings . the pressure reading goes back up to normal.  Turn the boost pump off and it goes down to zero.  So, the gauge is reading the Boost Pump but NOT the mechanical pump.

  What would cause my pressure reading to go down at higher power settings in an almost linear fashion?

  By the way . I checked the fuel venting and cleaned the fuel filter.  Everything is good on that end.

  Where do I begin?

  Tom



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