fuel Pressure

olderthandirt · #1 01-05-2017, 05:19 PM

so today coming back from flight the fuel pressure went to 5.7 PSI and started blinking yellow, I pulled electric fuse and it settled to 5.6 and no yellow blinking light..anything to worry about?? Also climbing out today at 75 MPH I was getting 5140 RPM not 5200 again anything to worry about???l Thanks

RFSchaller · #2 01-05-2017, 06:40 PM

Better high than low!

TS Flightlines · #3 01-05-2017, 06:56 PM

Seems to be all over the place---up and down. Early December it was low----hum
Tom

D&M Dan · #4 03-24-2017, 05:31 AM

Finally got some good flying weather in Upstate NY yesterday and was able to do the first flight. What a blast and what a great handling airplane.

I have a couple small issues, mainly with the Dynon, but the one that concerns most is with a fuel pressure warning on climb out. Pressure drops to 2.2psi and the "fuel pressure" starts chiming in the headset.

I have 18 gal. fuel onboard and engine is smooth as can be. Strainer was cleaned before flying. Fuel pressure in straight and level flight is 2.9psi and flow is 5.2gph.
Any ideas where to look?
Thanks,
Dan

Piper J3 · #5 03-24-2017, 06:46 AM

You should see ~ 2psi from the electric pump when master is switched on. When engine starts the mechanical pump adds ~ 3psi. So, with engine running and both pumps operating ~ 5 psi is what you should be seeing as normal operating fuel pressure.

BigJohn · #6 03-24-2017, 07:14 AM

Quote:

Originally Posted by D&M Dan

Finally got some good flying weather in Upstate NY yesterday and was able to do the first flight. What a blast and what a great handling airplane.

I have a couple small issues, mainly with the Dynon, but the one that concerns most is with a fuel pressure warning on climb out. Pressure drops to 2.2psi and the "fuel pressure" starts chiming in the headset.

I have 18 gal. fuel onboard and engine is smooth as can be. Strainer was cleaned before flying. Fuel pressure in straight and level flight is 2.9psi and flow is 5.2gph.
Any ideas where to look?
Thanks,
Dan

Dan, first of all you would probably get a better response on the forum if you had started a new thread with a more descriptive title. You have hooked on to an old thread that sounds like a different problem. Be that as it may, in order to make any kind of helpful suggestion more information is needed.

Fuel pressure with engine off and electric fuel pump on.

Ground run pressures at several RPM points ranging from idle to WOT. Do this twice, once with electric pump on, and agin with electric pump off.

Let us know results and we can go from there.

TS Flightlines · #7 03-24-2017, 07:18 AM

Dont know about alot of the 12 guys, but 2.2 seems to be the magic number on the fuel pressure.
Tom

D&M Dan · #8 03-24-2017, 08:45 AM

Will do as you suggested John next time I am able to get to the airport. What are most seeing for fuel pressure? Should I be in the 5psi range at all phases of engine run and flying?
Thanks

tomkk · #9 03-24-2017, 10:01 AM

I just checked mine recently. 2.8 psi on electric pump only, 5.1 w/ electric & engine pumps. I run both pumps in the air but did check the engine pump only in cruise and saw 3.5 - 4.2 on engine pump only. I tried that on another flight and saw as low as 2.? - don't remember the precise pressure but it was just at the bottom of the green on the engine pump only.

This is all with 93 octane auto fuel with 10% ethanol.

rvbuilder2002 · #10 03-24-2017, 10:49 AM

Quote:

Originally Posted by D&M Dan

Any ideas where to look?

With a brand new airplane the first thing to check should be the screen in the gascolator.
Once you start taxiing around and sloshing fuel in the tank it is not uncommon for some debris to get flushed out of the tank and hoses, and plug a portion of the gascolator screen.