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High Fuel Pressure on IO540

J

jimfaber

Member
I am reading what I would consider high fuel pressure on my IO540. It runs about 30 to 32psi on the ground and increases to 34 psi with the fuel pump on. It drops slightly at full power. In flight it is consistently reading 29 to 32 psi. with the fuel pump off. It will increase another 2 psi with the fuel pump on.

Is this something to be concerned about and what should I do to trouble shoot this?

I just bought this RV-10 in June and any help or suggestions would be appreciated.

Thanks,

Jim Faber
 
Welcome to VAF!

Jim,
welcome.gif
to the good ship VAF.

What brand of injection do you have?? Knowledgeable folks may want to know the brand to determine if the pressures are normal.

In my 10, with AFP injection that is about where my fuel pressures run.

Good to have you aboard, you are gonna love the RV 10.
 
Fuel pressure

I am no expert but I think I remember that somewhere around 30 psi is required for fuel injection atomization.
 
My IO-360-A3B6 with the Bendix RSA-5AD1 runs ~28-30 PSI on the ground, 32 PSI on the ground, and will do 34 PSI with the electric pump on. We recently replaced the fuel pump due to fuel pressure dropping to 12 PSI in flight at higher altitudes. It would go from 28-13 PSI randomly. According to Lycoming, 13 PSI is fine but you could feel the engine leaning out and the plane slowing down when the fuel pressure dropped. I didnt like it, regardless of what they said.
 
Mike S said:
Jim,
welcome.gif
to the good ship VAF.

What brand of injection do you have?? Knowledgeable folks may want to know the brand to determine if the pressures are normal.

In my 10, with AFP injection that is about where my fuel pressures run.

Good to have you aboard, you are gonna love the RV 10.
Click to expand...

Thanks!!

It is a Silver Hawk EX by precision airmotive.
 
Fuel Pressure

30 Psi is what you want with fuel injection. It will not work right with out that pressure. 15 Psi is what carbs will want to see with engine running.

You are perfectly fine.

My Piper Saratoga runs between 30 and 25 all the time and it runs great.

IO540k1g5
 
25 PSI

The AFP fuel pump is calibrated to produce 25 PSI.
The high pressure mechanical fuel pump also produces <25psi>
I don't see anything wrong with 30 psi but 25 generally considered normal.
I believe the new EFFII pump is calibrated to produce 30 PSI.
More pressure will reduce the chance of vapor lock.
Can't remember exactly but fuel injection still runs fine at 15 psi or even less.
 
With the same AFS and Dynon setup I am getting about 24 with the engine pump and about 34 with the electrical pump on.
 
Thanks for all the information. I have come to the conclusion that my condition is fairly typical. I will move the yellow range on my AFS 4500 to start at 35psi and turn red at 37 psi or above.
 
Acuracy?

What kind of sensors are you using? Here's been my experience on the same airplane (RV10 with AFP injection):

VDO sender: reads 27 PSI
Stewart-Warner: reads 30 PSi
Kavlico: reads 22 PSI

All I did was change out senders and change the calibration table appropriate to the sender. I need to get an accurate direct-reading gauge and stick it on there. However, I noticed in some of Rob Hickman's pictures that his reads 22 PSI with the Kavlico sender as well, so I'm thinking it's OK. :)

Vic
 
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