Wont start - tested fuel pressure, need advice

[40BelowSummer]

Immediately losing fuel pressure after fuel pump prime - new fpr

Ive just about got my supercharged SHO running after 2 weeks. It got a new SHONut (mallory) adj. fuel pressure regulator/suspension/brakes/wheels/tires and other non-related goodies.

The car has ZERO fuel pressure after about 2 seconds when the ignition is turned on. It goes up to about 20 very briefly them immediately back to zero. The fuel pump primes everytime.

The fuel pump is priming and pushing fuel into the fuel rails (as indicated by the gauge) then immediately back into the fuel tank (which I can hear I believe). Is this because of a bad return check valve or perhaps my new Adjustable FPR is somehow allowing all fuel into the tank Or is there a check valve on my fuel pump that is bad making me have to replace the whole pump?

Thanks!

I have an aftermarket fuel pump (not sure what size)

EDIT: When I hooked up jumper cables to the car I left the ignition on and was cleaning the connection on the car giving the jump. In the process I prob closed the circuit about 50 times which made the fuel pump prime alot. At one point I heard a faint boom or pop noise which I think came from the fuel tank. But the fuel pump still works fine. Did I blow a line or check valve perhaps?

 

[Ishodu]

You should read the directions and then set the pressure see where that gets you.

 

[40BelowSummer]

Read the directions and adjusting it gives me no different results.

 

[projectSHO89]

A Fuel Pressure Regulator (FPR) is analogous to a dam on a river.

It is there is keep the level at a minimum height (pressure).

Yours sounds like a dam with a floodgate open, ie, open regulator.

Steve

 

[40BelowSummer]

Ok the car does start

I adjusted the Adj. FPR fully closed and got a spike of about 60psi when the key is turned on. I opened it all the way and got no fuel pressure when the key is on. I adjusted it so it spikes up to about 39psi when the key is on. It is still immediately going back to zero. Another thing thats weird is when I ground the fuel pump circuit using the EEC harness I get different pressures than when the key is on. I cant get more than 20psi by grounding it.

What are the symptoms of a bad return line check valve? I dont think it is the NEW regulator, I have fully adjusted it with an expected difference but only for about 1 second after the key is turned on. Its still immediately losing fuel pressure after the fuel pump primes.

Thanks

 

[40BelowSummer]

I removed the fuel pump assembly to check it out and see what pump I have. I have a Walbro 255lph pump. Is there anything I can check for while Im in here? I dont really see how the return line check valve can go bad (assuming its the orange rubber duck call thing)

 

[40BelowSummer]

Sorry for the back-to-back posts but I need to get this figured out.

Would the return line check valve effect fuel pressure when the engine is running or only when off? It is after the regulator which should determine the pressure right?

Also is there a check valve on the Walbro pump? If so how do you tell if its bad? I need to figure out why Im immediately losing fuel pressure when the key (fuel pump) is turned off.