: loss of fuel pressure

10-28-06, 02:37 PM
I posted a while back on a harder than heck to start 1999 Deville. As soon as you shut the vehicle off the fuel rail has no pressure in it. I have pulled the injectors off and tested and none of them leak. I replaced the FPR valve. I was told the check valve in the fuel pump was bad in my previous post. I replaced the fuel pump and still have the same problem? What in the world could it be? The new fuel pump is putting out 45lbs of pressure. The second the key is turned off the fuel rail loses pressure.

Thanks a million for the help ahead of time

10-28-06, 04:25 PM
If it holds a steady ~40psi when running, the pressure must leak either through the FPR or pump when shut off. Since it holds the 40psi, I would suspect the pump.

10-28-06, 05:32 PM
very probably a defective pump.