5.7 GSIPEFS fuel pumps

[Dave-R]

I have a 2001 5.7 GSIPEFS with throttle body fuel injection. Took it to lake Powell and it ran fine,except you could at times at idle hear the fuel pumps whine.
The engine ran fine, but when I got home I wanted to check things over. I pulled the fuel cell apart and it was clean. I could not find any screens in the pumps or paint residue that others have found. I re-assembled and replaced a 1 month old filter with a new one,and checked the fuel pressure at the low pressure Schrader valve. (about 6psi ) I then checked the outlet of the high pressure pump and got ( 0 ). The engine runs fine and revs right up. I'm puzzled by this so I unplugged the high pressure pump. She starts, then dies every time. I am positive that it is the high pressure pump I am testing. It is on the right side of the cell.. I will pull the high pressure Schrader valve out to see if it is blocked. How could the engine run so good with no fuel pressure ? I looked at the injectors and I will try to find the regulator and see if I can find a screen there.Can anyone give me some pointers on the fuel regulator like can I pull it apart without ruining the gaskets, and if it has a screen. Any Ideas will be a appreciated. Dave-R

 

[DCinVA]

The most common cause of the fuel pump whine is air in the fuel line. This can be caused by a number of things such as a blockage in the filter, line, or pickup tubes in the tanks, or a bad anti siphon valve. There is a great tutorial in the adults only section on diagnosing fuel issues. One section describes temporarily adding a piece of clear tubing to your fuel line so you can check for air bubbles.

 

[Dave-R]

Thanks DC. It doesn't seem to be as loud now. What I can't figure out is there is about 5 lbs on the low pressure Schrader valve, but 0 pressure on the high pressure pump. The engine seems to run fine. That I don't understand. If I unplug the High pressure pump, the engine dies. I can't figure out how to remove the fuel regulator, to check the screens or to see if it is stuck open, which would make some sense. I loosened the 3 torque screws but the fuel hose fittings kept the regulator from coming up from the throttle body. Any one have any experience pulling a regulator off. I ordered a new high pressure pump today. Dave-R

 

[DCinVA]

The engine will not run with no fuel pressure on the high side. The test port is either blocked or you are not installing the gauge correctly. It is similar to testing your tire pressure, you need to push in the little pin on the Schrader valve to check pressure. Check your gauge to make sure you are installing it properly and that it has a provision to push the pin in. Then check for blockage by unscrewing the Schrader valve on the high side and making sure the port is clear. There is a special tool to unscrew the Schrader valve. Any good auto parts store will have one for sale.

 

[Dave-R]

That's exactly what I thought DC. I took the Schrader valve apart, cleaned it and am able blow back thru it when I press the spring pin in. My fuel pressure gauge reads about 5 or 6 psi when I test the low pressure pump. I will buy a new Schrader valve and try again. If the fuel regulator is failed open would that account for the 0 pressure reading? I am going to start the engine tomorrow, and recheck it. Dave-R