Correct. The liquid/air mix enter the orifice .... then open a ball/spring starting at "16-21" psi.asavage wrote:In your picture, it looks as if that's a slide valve (shuttle valve). The hole bleeds a little air, and when pressure comes up the whole inside gizmo moves to reveal a larger passage.
What the Nissan fails to make clear is: The OFV orifice pass is MUCH LET LESS fuel .... BOTH than .... the ability of the Lift Pumper pressure pressure and volume. (I still have short speech) I first become aware AFTER rebuilding the Lifter Pump.
"16-21" psi only means when the OFV orifice opens ... it does NOT limit the fuel line (lifter to injection pump) to "16-21" psi.
The new Lifter Pump present (don't know the Original lift pump) resulted the fuel line pressure exceeded "16-21" psi... passed over 30+ psi (my dial pegs 32 psi with only a slightly RPM aboved idle.).
I corrected this first design installing using a "adjustered pressure vent" .... that has about 1/8" capillary and a adjustabled ball/spring. This has shown capable Lift Pump 20 psi and flow vent and at the injection location.
Note: the external seen ball/cylinder is physically move as needed.
Note: I've come up with a later version better ... but haven't not shown it here.