there needs to be a restriction to build pressure on the pressure side. the restriction being the fpr. so when you turn the car off the spring pressure keeps the fpr blocked from return and the check valve in the pump keeps it blocked from going back into the tank so it should hold pressure through the rails.

 

its normal to leak down fuel pressure once the car is stopped. the FPR leaks as well as the check valve at the pump.

 

FPR doesn't seal tight. It's only a ball sitting in a seat which is open due to pressure when the pumps are running so it has no reason to be completely sealed to hold pressure when the car isn't running.

I'm not sure how AAM sets their systems up but there is no reason to set it up so it holds pressure after the car is shut off.

 

if it didn't hold pressure, like mine was before, then you would be cranking for 10-15 seconds every start, while you built pressure. then once pressure is built the car would start. the check valve in the pump should hold pressure, we actually had a recall on the versa's here awhile back for extended crank due to the check valve failing. as for the fpr it will hold pressure till whatever you have it set to (say 50psi) then after that the pressure forces the ball out of the way causing it to return. under that 50psi the pressure is not strong enough to push the ball out of the way, therefore no return, thus holding pressure.

 

Good thing this isn't a versa with a RETURNLESS system.

This is a return fuel system. It is nothing like a returnless system. My car fires right up like the day I rolled it off the dealership lot. This is far from my first rodeo and I'm not just an internet jockey talking about what I heard on the forums.

BTW, if it takes 15 seconds to build pressure in those fuel lines you have some serious problems with your fuel pump. It should take less than 1 second from power hitting that pump to have pressure at those injectors.

 

just saying man, im just comparing. the 350z stock returnless system holds pressure just the same as any other car. it should still hold pressure. if i go out to my car right now after not driving it for 10hours and I pull the pressure line off the pump fuel will spray out. but doesnt matter, I fixed the issue.

 

ya, returnless systems do hold pressure. Return fuel systems (which is what you said you have) do not. 2 completely different designs of fuel systems.