2006 Subaru Legacy 3.0r Spec B 71000 miles.
Port injection
Fuel Pressure Regulator
Fuel return
PWM controller on pump
Electronic Fuel Pressure Gauge installed on fuel rail
No factory fuel pressure sensor for ECM
During WOT pulls, my fuel pressure can be seen to dip.
Manufacturer specs are 40-43psi with vacuum hose connected to FPR. 50-53PSI with vacuum hose disconnected
My readings:
FPR vacuum connected: 39psi
FPR vacuum disconnected: 47psi
Fuel pressure builds to 47psi with throttle pinned to floor, WOT. From 2,000rpm
As the revs increase, fuel pressure starts to dip down to 40psi, the fuel pump duty increases around 5,500rpm and it jumps up to 50psi
What is causing this behaviour? Am I correct in thinking the fuel pressure should remain at manufacturers spec of 50-53psi throughout the entire rev range?
do you have any driveability issues?
It seems a little unresponsive at times, not the best fuel economy and I can see a few random misfires on the subaru select monitor. It's not awful but it's definitely noticeable.