Fuel Pressure Bleed off question

[1fast97gsx]

When I shut my car off my fuel pressure guage reads around 43 psi. Then about 10 minutes later it's still at 43 psi. Once I go out and look at the guage the next morning it's at 0 psi. I didn't think it was supposed to drop much lower than 20 psi or so ever so I'm assuming there's a leak somewhere but I couldn't dig up too much info on what it should actually bleed down to and how fast.

Fuel mods: Walbro 255 pump, stock regulator, pte 780 injectors. I have an aeromotive regulator on the way and injectors all meassured the same resistance across.

 

[pneumo]

I've seen the same thing on my cars. I'd say it's normal. Even with zero psi on the gage there is still fuel in the rail so pressure comes up as soon as the fuel pump kicks in. I've never had a problem starting my cars after they've sat unused for several days. I just assumed the pressure eventually bleeds off through the fpr, or through the anti backflow valve in the pump.

 

[GTM]

...
Once I go out and look at the guage the next morning it's at 0 psi. I didn't think it was supposed to drop much lower than 20 psi or so ever so I'm assuming there's a leak somewhere but I couldn't dig up too much info on what it should actually bleed down to and how fast.

Put a ViceGrip or hose pinch off plires after the Pressure regulator. If the pressure remains overnight then the regulator is leaking.

Next pinch the inlet hose to the engine if the pressure drops then the injectors are leaking, if not then the pump is leaking.

If one or more injectors are leaking you would have hard start in the morning with 1 or more cylrs misfiring. I've seen pressures all over the place, some that will hold pressure for days and others that only last minutes. It doesn't take but a second or two to build max pressure I wouldn't worry about it unless it's causing starting problems in the morning.

Most of the pumps I've seen have a replacable nipple with the check valve built in. I've seen these balls and springs get rusted and lacquered up so a good thing to inspect if you suspect a problem.

Cheers,
GTM