Fuel Pressure fluctuations? problems?
in 912 / 914 Technical Questions
12 years ago
912ULS, no return line, Kitfox model 5. Facet aux fuel pump in series with original mechanical pump.
MGL Xtreme EFIS newly installed with a new 0-7psi sender they recommend, so I have no historical fuel pressure information.
Here's the issue:
When I turn on my pump before engine start, my MGL EFIS shows a nice 3psi stable pressure.
When the engine is in cruise flight, it will make sudden pressure drops down to 2 PSI sometimes
even 1 PSI for a couple seconds then back up to 4 or 5psi. This fluctuation will happen a couple times a minute once it gets going.... my pressure never 'stable' like I wish it was - in my mind no gauge should be swinging that erratically, it doesn't lend any confidence! All else about the motor is great, and fuel flow is pretty consistent so no symptoms there.....
Some reading in the forum here implies this may be a common situation? Is this correct?
If so, it's still disturbing, what do you recommend? Is this a 'problem' or a symptom of
my non-return-line configuration? Would adding the return line and oriface stabilize this
erratic pressure reading? OR do I have something else going on?
Big zinger: should I be concerned? I would like to perfect / smooth out the readings even if it's not a safety concern.
Thanks for your help!
MGL Xtreme EFIS newly installed with a new 0-7psi sender they recommend, so I have no historical fuel pressure information.
Here's the issue:
When I turn on my pump before engine start, my MGL EFIS shows a nice 3psi stable pressure.
When the engine is in cruise flight, it will make sudden pressure drops down to 2 PSI sometimes
even 1 PSI for a couple seconds then back up to 4 or 5psi. This fluctuation will happen a couple times a minute once it gets going.... my pressure never 'stable' like I wish it was - in my mind no gauge should be swinging that erratically, it doesn't lend any confidence! All else about the motor is great, and fuel flow is pretty consistent so no symptoms there.....
Some reading in the forum here implies this may be a common situation? Is this correct?
If so, it's still disturbing, what do you recommend? Is this a 'problem' or a symptom of
my non-return-line configuration? Would adding the return line and oriface stabilize this
erratic pressure reading? OR do I have something else going on?
Big zinger: should I be concerned? I would like to perfect / smooth out the readings even if it's not a safety concern.
Thanks for your help!
