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  #11  
Old 03-24-2017, 12:03 PM
Mich48041 Mich48041 is offline
 
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Whatever the fuel pressure readout is displaying, it is meaningless until verified. Those fuel pressure senders are notoriously inaccurate.
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  #12  
Old 03-25-2017, 08:59 PM
RFSchaller RFSchaller is offline
 
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Wow! thirty years of flying without a Fuel pressure indication, and I'm alive! Whod'a thunk it!😈--- just sayin'.
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  #13  
Old 03-25-2017, 09:30 PM
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MartySantic MartySantic is offline
 
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Many of us have seen decreasing fuel pressure on climb out. Many have seen decreasing fuel pressure when descending from high altitudes.

Search this forum and you will find a number of threads related to the fuel pressure anomalies.

I do not believe anyone has found the root cause after ruling out the obvious, ie. sensor issues, gascolator issues, etc.
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  #14  
Old 03-26-2017, 07:39 AM
D&M Dan D&M Dan is offline
 
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Marty,
I find this problem concerning and as I posted in another thread last week, my first flight "fuel pressure" warning in the headset had my attention on takeoff. The engine did not miss a beat however and I continued the flight, even completing 4 takeoffs and landings. The warning is coming occasionally as pressure drops into the 2.0psi range on run up and climb out.

As this is a brand new aircraft, before I fly again I will go through all options including flushing the fuel system again, cleaning the strainer screen and carb bowls and checking the vent system. Also as Big John suggested I will log pressures in all phases of engine run, including idle, WOT, and 4000 rpm run up. With and without the electric fuel pump. I am not sure however this will solve anything. I feel as if there maybe something else going on for so many to report this issue.
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  #15  
Old 03-26-2017, 08:49 AM
John-G John-G is offline
 
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Quote:
Originally Posted by Mich48041 View Post
Whatever the fuel pressure readout is displaying, it is meaningless until verified. Those fuel pressure senders are notoriously inaccurate.
Dan --- Joe has given you some good advice here. Prior to taking the time spinning your wheels recording a bunch or readings, first tap into the fuel system and verify with a pressure gauge that the fuel pressure readings the fuel pressure sending unit is sending to the SkyView is correct.

A good point to begin would be using the pressure gauge to make a reading with the engine off and the electric fuel pump on and see how it compares to the reading the SkyView is displaying. Repeat with the engine running.

May also be a good idea while your at it to have another person monitor the cockpit displayed fuel pressure while you slowly and gently move and flex the wires to the fuel pressure sending unit at the connector or any splices you may have to verify the pressure drop is not caused by a faulty wiring/connector issue.
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  #16  
Old 03-26-2017, 10:37 AM
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MartySantic MartySantic is offline
 
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Dan,

May I ask where you have your fuel pressure alarm set at? Back in 2011, Van's solution to the fuel pressure issue, reported by many, was to set the "red-yellow" alarm point at 0.7 psig. (RV-12 Presets document). See my thread from years ago. I did not follow their advice and left it at 2.1/2.2 psig.


http://www.vansairforce.com/community/showthread.php?t=75825&highlight=2.1+psig


Maybe many now have the alarm set to 0.7 psig? The current POH states a 2.2 psig alarm point.
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Last edited by MartySantic : 03-26-2017 at 10:40 AM.
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  #17  
Old 03-26-2017, 10:39 AM
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Tony_T Tony_T is offline
 
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Quote:
Originally Posted by D&M Dan View Post
Marty,
-----
As this is a brand new aircraft, before I fly again I will go through all options including flushing the fuel system again, cleaning the strainer screen and carb bowls and checking the vent system. Also as Big John suggested I will log pressures in all phases of engine run, including idle, WOT, and 4000 rpm run up. With and without the electric fuel pump. I am not sure however this will solve anything. I feel as if there maybe something else going on for so many to report this issue.
If you have SkyView or D-180 you don't have to manually log anything.
As you say you have a new airplane (with SkyView?) you may be not be aware, that you can very easily dump a data log to a USB stick and analyze the data on a free website: savvyanalysis.com. And you can get a graph of anything that the EFIS sees. This is a very useful tool for troubleshooting. You don't have to pay unless you want Savvy to analyze a problem for you.

You can plot your fuel pressure coincidental with other parameters, here is a plot of fuel pressure and rpm.


You can do the same thing with the D-180 except it's not quite as easy there you have to hook up a laptop to the D-180 using the factory supplied dongle. With SV you just dump the data log to the USB stick and take it home with you. One of my RV12 pals looks at his data after every flight! He's plane crazy.
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  #18  
Old 03-26-2017, 12:05 PM
D&M Dan D&M Dan is offline
 
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Marty,
the alarm sounds when the pressure drops below 2.2 psi. therefore I believe it is set as you described.

John and Tony,
Thanks for the advise. I will verify pressure with a gauge and check connections. Also will download the data as described.
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