Quote:
Originally Posted by andrewwynn
@80s: I don't think what you said is accurate with the relief valve for the siphon jet. I've watched the pump while running and fuel only flows from the siphon jet outlets normally. My understanding is that the pump provides perhaps 60psi, the pressure regulator moderates that to 50 and relieves the extra pressure and volume back to the siphon jets at approximately 15-20 psi .
I do not know if the check valve is at the pump or the pressure regulator.
The FPR shows as compatible with my model when attempting to buy either Amazon or fcp euro as well as a recent thread on xoutpost showed somebody changing the FPR piqued my curiosity.
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Yes, there will be fuel at the syphon jets as long as the pump can overcome the fuel pressure (40 or whatever PSI)regulator, at that point the rail pressure will increase with increased flow to the point the syphon jet relief valve opens. Normally the exhaust side of the pressure regulator would go back freely to the tank and not be used for the syphon jets which is why this can be confusing. This is also why the pressure drops from the 50 to 40 as soon
as you turn the engine off.
Both the pump check valve and the fuel pressure regulator need to hold in order to maintain pressure when the engine is shut down.