fuel pressure problem

[Jeanluc]

My new 1990 TPI (install on a 1982 Vette) have the following problem:
Fuel pressure is correct when engine is running (41 psi at idle)
But with ignition on/engine stop, psi drop to 40/45 psi and go down immediatly to zero....
Engine start with difficulty when is cold....
fuel pressure regulator problem or a injectors leaks???

thanks to help me

JeanLuc

 

[Twin_Turbo]

Somehow the pressure is bleeding off, does your pump have an internal checkvalve? You might want to try to put one in the fuel line, close to the tank. That will help prime the system when the car has sat for some time.

 

[yellow77]

Pretty much what TT said, there is a check valve in the pump and when this goes bad, the pressure will drop to zero immediately you shut off the engine.
On my sons Trans Am with TPI, I installed a small switch which turns on the fuel pump relay when pressed. He uses this to prime the system during cranking.

Hope this helps

Cheers

Richard