Hi Robert;
I suggest you test the EI fuel pressure sender you got with your CGR 30.
I don’t know what model Piper you’re flying, but the following test would be very simple to do on my Comanche because I mounted the fuel pressure sender on the firewall.
Disconnect the hose to the fuel pressure sender, or if it’s screwed into a fitting, unscrew it. Leave the wiring attached. Rig up a test set up–probably wouldn’t need more than a pipe union that your mechanic might have (or he could buy an expensive one at the local hardware store). Screw the sensor into one end of the union and a way to apply air pressure to the other end. Put an air pressure regulator in the “air in” end of the union.
Apply 3-5 psi if your engine is carbureted or and a pressure that’s in the mid range of the fuel pressure limits of your engine if it’s fuel injected. Then check the read out on the CGR 30. Turn on power to the CGR 30.
Is the FP reading solid? or does it jump around. If it jumps around, I’d get another sensor.
If it does not jump around, I would look closely at the hose, if there’s a hose connecting the sensor to the engine.
Since I don’t yet know the model Piper you’re flying, I’m doing a little guessing here, but if the FP is good with the boost pump on, that seems to indicate that the engine driven FP is glitchy or there’s some kind of obstruction in the line. An obstruction could cause a higher than desired fuel pressure. I would temporarily plumb in what we call a direct reading fuel pressure gauge by “T” ing a fitting into the fuel pump “out” hose so you can read the pressures the pump is producing when the engine is running.
Let me know what you find.
Steve
