Randy
1972 PA32-300
- Joined
- Aug 3, 2012
- Messages
- 68
- Reaction score
- 20
I have a 1972 PA32-300 with a Lyc IO-540-K1G5. This is an injected engine. The cockpit fuel gauge shows very low fuel pressure at high power, typically on climb out, if the electric boost is turned off. (I know the handbook says to keep the boost on during climb). I have had the engine stumble when the pressure drops. Occasionally in cruise, at typical cruise power setting (2400 RPM/24 inches MP) the fuel pressure will dip low (again with boost pump off). Our A&P changed out the mechanical pump last year. No real difference. He checked the pressure with his own gauge and found pressure to be 18 PSI at close to full power with boost off and 23.5 PSI with boost on. He says the fuel flow is good.
The A&P called the pump maker who said this pump uses a plunger. At high power, the plunger may not fully return before the next down stroke, hence it may produce lower output (pressure) than at lower power setting. Our pump, being newer, has a stronger return spring, but may still have this issue. The A&P says it is safe to fly, just use the boost as the POH calls for on full power climbs. He also says the panel gauge reads 2 PSI low, which is some comfort.
Has anyone else expereinced a low fuel pressure issue like this? And if so, what did you do? Thanks, Randy
The A&P called the pump maker who said this pump uses a plunger. At high power, the plunger may not fully return before the next down stroke, hence it may produce lower output (pressure) than at lower power setting. Our pump, being newer, has a stronger return spring, but may still have this issue. The A&P says it is safe to fly, just use the boost as the POH calls for on full power climbs. He also says the panel gauge reads 2 PSI low, which is some comfort.
Has anyone else expereinced a low fuel pressure issue like this? And if so, what did you do? Thanks, Randy