After replaceing the fuel filter last July, we noticed a longer cranking time before the engine started. The problem would go away by turning the key to ignition and waiting a moment before cranking. I recently replaced the fuel pump because of sudden noise from the pump (Carquest replacement pump). Now the engine cranking but not starting is worse. I put a pressure gauge between the filter and fuel rack and get 40 pounds (steady) when running but the pressure drops to 0 within a minute after turning off the ignition.

 

Questions: Besides the fuel pressure regulator, what keeps the pressure from bleeding back to the tank?

 

Is the pressure supposed to stay up after shutdown?

 

P.S. It sure would be nice to find a good repair manual for Subarus newer than '96.

 

Thanks.

Welcome.

 

Yeah I'd think pressure shouldn't go right to 0 after you shut off the car.

 

Your gas cap is on and working properly right?

 

When you installed the pump, everything went back together ok?

 

BTW, how much did you pay for the carquest pump?

I understand the gas cap situation and don't believe that's a problem.

 

The pump installation was rather straightforward; the pump price was $97.

 

The Carquest strainer is a little mis-shaped and presses against the bottom of the tank, causing noise. So a strainer from a Subaru dealer is probably the best choice.

 

I assume that the two things that would hold pressure are a check valve in the pump and the fuel pressure regulator. Is this correct?

 

Thanks.

I can't comment on the internal configuration of the pump, and whether there's a check valve. But yes, the pump (in some way) and the fuel pressure regulator would be the devices that are going to maintain pressure after the engine is turned off.