Fuel pressure

[838315]

I have a RV-7A with a 0-375 with carb.and two 10" Skyviews. When I pull about 1.5 to 2 Gs (just a quess no G-meter yet on the Skyview)
The fuel pressure will drop from 3 to 4.5 pounds to less than a pound. Has anyone else had this happen? Any ideas? The sending unit is mounted high on the firewall. The fuel pressure is kinda all over the place anyway.
Thanks,
Larry

 

[N707RW]

Larry,

As odd as it may sound, I've seen this in a couple of other RVs including mine. My solution turned out to be a bad ground on the fuel sender. Although the sender is mounted into a manifold (I'm assuming you used the manifold Van's sells, like most did) you would think it would be grounded through the mechanical screw-in connection, but it turns out that that isn't a very good ground. I used a large hose clamp around the sender to clamp a wire to the unit and ran it over to a ground point on the firewall. I had intended that to be only a test (it does look kind of hokey) but it worked so well that I haven't changed it.

I hope that will help with your erratic fuel readings.

-- Rich

 

[dynonsupport]

Without doing any research, note that the sensor itself is a mechanical device (pressure pushes on a diaphragm, which rotates an arm over a coil) . Depending on the orientation of the sensor, it doesn't sound unreasonable that Gs could actually affect the sensor physically and cause a momentary dip in the reading. Also could be a real pressure anomaly, or possibly a bad sensor.

 

[65xx]

Would the orientation of the pressure sensor have any effect on the rotating arm thingy? I have mine mounted normally on Van's manifold in the horizontal position. Would rotating it a quarter turn have an effect? Dan