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Fuel pressure 0-360 A1a

laz

Well Known Member
I have about 12 hours on my RV8 and things are going reasonably well, first flight was on March 4 and running down some small issues. I have a Garmin G3X touch system and was wondering what the normal fuel pressure should show.

Lycoming says " 8 psi Max, .5 Min, and 3 psi desired).

I am indicating around 2.7 to 2.9 at 24 squared. everyone seems to be running fine but just curious what psi most people get with a car. 360.
 
I checked several flights and I seems to run about 4.7 psi in cruise. I think the minimum for the MA4-5 is about 1/2 psi, but I would not want to go that low.
 
Historically RVers with carbs have seen a wide range of fuel pressure, often within the same flight. This variability seems to be related to pressure sensors not being consistent at low pressures. There are numerous threads about this situation in the VAF archives.
 
I had low fuel pressure readings for a few years, usually while climbing. It would go to .5 and sometimes lower.
Same engine as you. We have a dynon . Finally got the newer type sensor and it solved the problem . Never goes below 2 and usually 4 to 5 .
 
I had low fuel pressure readings for a few years, usually while climbing. It would go to .5 and sometimes lower.
Same engine as you. We have a dynon . Finally got the newer type sensor and it solved the problem . Never goes below 2 and usually 4 to 5 .

For us newbies - who may have purchased an RV with this issue :) -- what new sensor is this?
 
Compatible with VANS steam gauge ??

I have the same annoyance with below green pressure on a Vans steam gauge. Boost will always get a higher reading. Does anyone know if Kavilco will work with vans steam gauge ?
 
Thanks to all for the reply's. I can take "screen shots" with the G3X and I have a couple with 3.1 and 3.2 psi a cruse. I believe this is just a gauge issue. It just seemed strange that with a new fuel pump and all new everything it should be less that the 3 psi. I have the airflow performance fuel filter that Van's supplies and will pull and clean it this week.

The engine is developing great power and have never had any issues. Just thought it should be higher.
 
Check sensor

I used to see fuel pressures all over the map and low pressure alarms just about every flight. Changed to new VDO sensors and pressure now read 4.7 pretty consistently.

Paul
 
Same engine in a FP -6A

Cruise shows a pretty steady 3.4 psi, lowest was 2.8 psi in a 500 fpm climb with the boost pump off. Take off climb was 5.2 psi ith the boost pump on.

Above with a Skyview and the old Dynon VDO fuel pressure sensor.
 
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