Thinking of installing a check valve?

[irving]

My cayenne is loosing fuel pressure when off. I have replaced both pumps and pressure regulator. I have ordered a new filter. What is the problem with installing a check valve on the fuel line? Seems like a simple fix. Any comments appreciated 

[JFP in PA]

54 minutes ago, irving said:

My cayenne is loosing fuel pressure when off. I have replaced both pumps and pressure regulator. I have ordered a new filter. What is the problem with installing a check valve on the fuel line? Seems like a simple fix. Any comments appreciated 

Simple: It may not solve your problem.  You need to find out where the fuel pressure is venting, say at an injector, and fix it before it causes more problems, like scored cylinders.  Simply adding a check valve is a band aid; find the real problem and fix it.

[omolddesign]

Are you sure its not the recall issue for the pump seal in the tank

[irving]

I had that fixed a month ago. I pressurized the fuel line to the tanks and at about 20psi bubbles came up from one of the pumps. Thought I had my answer, but then when I continued to add more pressure bubbles came from the other pump.

 

I turned the pressure in the direction of the fuel rail and it held.

 

I need to figure where my pressure leak is coming from. Any ideas are appreciated