N788RV

N788RV

Active Member
I have a Superior IO-360 and a Dynon EMS-120. My fuel pressure was running about 30 psi/34 psi with out/with fuel pump. At the first annual which was about 4 mo ago I found very clean fuel filters both strainer and airflow performance. I recently have flown about 7000 miles in the last month and did a software update to my dynons. A couple of sortie ago my fuel pressure indicated about 46 psi then eventually droped into the proper range of 2-35 psi. Now it consistantly reads about 46 psi with or without the fuel boost pump. I'm guessing the fuel strainer is clogged as the pressure sensor is down stream of the airflow performance filter but I don't understand how something could have gotten past that filter into the fuel strainer at the engine. I'm looking for advice before I tear into. We all know how hard it is to get to the airflow performance filter and I was also wondering if maybe the software update could have caused this. Any advice.
 
It sounds like to me that something may have gone fishy with the update. If it were me, before I jumped into tearing the aircraft a part, I would trying to find a fuel connection that I could plumb in a mechanical fuel pressure gauge. Very simple to do, just use an AN "t" fitting with the mechanical gauge connected it to it with a hose. Run up the aircraft and compare the pressures between you EMS-120.

If the mechanic gauge shows the proper pressure and the Dynon does not, your sensor may be bad or not communication corretcly with the update.
 
I think you have indication issues. 34 psi, your normal reading is even high when compared to the norm of 21-26 psi in cruise. I agree you should try a direct reading gauge to check system accuracy.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
Fuel Pressure

I have the same setup as u, except I have the DEK-180. Why don't u fire this question to Airflow Performance and the the Dynon support forum to see if anyone else has had the same experience. My pressure runs right in the zone. U might also check to see if u reassembled the airflow performance filter element correctly for filter orientation and operation.

FYI...
Additionally, since my filter location is such a pain to access, I am going to relocate it to a accessible location in the cockpit using custom flex hosing. Taking this filter assembly apart every conditional is tough on my line flare...it's a matter of time before the material weekn's and leaks.

Zman
 
Thanks guys, I haven't had a chance to get to the hangar and take a look but I appreciate your suggestions.
 
Another possibility (happened to me) is that the fuel pressure sender is not completely grounded. I had high-P spikes but once it was grounded properly, they went away.

greg
 
Hi Fuel Pressure

Thanks! I studied a diagram of the pump configuration and after getting off the phone with airflow performance I'm pretty sure I have a bad fuel pressure transducer. With the boost pump off it should have been reading 21-26 psi and with it on it should never be able to get above 31 or 32 psi because of the pressure bypass valve. I will probably just opt to buy a new one and swap it out. $35.00 beats tearing the luggage compartment out to get to the fuel pump last filter until my next annual. Thanks
 
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