Fuel check valve and the 3port fuel pump Options

[brant]

I think there must be a check valve built into the 3 port djet pump

I believe mine is not working
(Hard starting symptoms)

Has anyone pulled theirs apart?

Pictures or a thread?

I'm also wondering if adding an in line check valve would work?

[Dave_Darling]

The pump itself acts as a check valve, at least to some extent. There is no specific check valve built in. There is a spring-loaded valve, but its intent is to bleed off overly high pressure from inside the pump back to the tank.

--DD

[brant]

The pump itself acts as a check valve, at least to some extent. There is no specific check valve built in. There is a spring-loaded valve, but its intent is to bleed off overly high pressure from inside the pump back to the tank.

--DD

Dave,

I'm having a Djet problem where after the car has set for one minute (or even over night) it is hard to restart

cranking the starter for approximately 30 seconds works, and everything runs fine
turning the key on about 4 times, to prime the fuel system yields a totally normal quick start

(I can hear the pump run for the 1 second activation when the key is turned prior to engaging the starter)

Prior to this problem starting up, I had tested/rebuilt all of the injectors and verified fuel pressure

obviously I need to check the injectors again for a possible leak/failure and check the fuel pressure again

the only winter modifications in the induction system were new hoses and relocating the pump from the front belly pan area, to the just below the tank area (a la 1975 style)... so the pump moved about 10 inches higher into the chassis and I suppose that could effect the bleed back a little?

I was never boiling fuel or having a hard to start problem before
I verified fuel pressure after the fuel pump slight relocation

I'm wondering if a failed fuel pressure (stock style) regulator could fail and allow all of the sitting fuel pressure to bleed off down the return line too.

my current working theory is that
1) pressure is bleeding out an injector (although it doesn't seem rich when it starts)
2) pressure is bleeding out through the feed line or pump
3) pressure is bleeding out through the return line or stock style pressure regulator

I have not tested yet.
I will be able to test this weekend to verify that the pressure is bleeding off
but during the 1 second pump prime with the key on, I can hear the pump change tone as if it is re-pressurizing the system and this is what led me to the de-pressurized-system theory.

gas mileage is still 30 -34mpg on the highway so I doubt the injectors are leaking but need to verify.

thus my thoughts about a check valve.

brant