Fuel pump help, fuel pump pressure return Options

[porscheteck914]

Hi Fellows , I need some help /advice . 1973 914 1.7 with original Fuel Inj. Djet . Original 50 year old fuel pump -3 ports. When I go to start it , I have to bump the ignition switch 2 times to get it to start. Fuel pump runs . I have a fuel pressure gauge hooked up to drivers side fuel rail. Pressure goes to 36lbs when I turn on ign switch. When I turn off ign switch, pressure immediately drops to 0 psi. The real question is : Does the fuel system supposed to hold pressure or slowly leak down after ign switch is turned off ???? Does fuel pump have a pressure valve in its return to tank, to hold some pressure ? Do I need a new fuel pump ? thank you for any help . (IMG:style_emoticons/default/confused24.gif) Paul

[brant]

For the original poster

You are correct
The 3 port original design should hold pressure when the car is shut off

I had to replace my pump when I had the same problem you are describing. Pressure would bleed to zero requiring much more cranking to start because of the lag for that pressure to rebuild


Turning the key/hearing the pump build up pressure 3x before I starting would help my car start without the excessive cranking


Changing the pump fixed it

And I tore my old pump open and saw the actual seal that was failing when I did it years ago


As mentioned 20-30 psi is the correct setting for fuel pressure
But changing your pressure back to 30 psi will not fix the bleed off problem by itself