Fuel leak and high pressure reading

[Palmettogasman]

I have a 1969 Camaro/ls1 (1997 corvette donor) build. I installed a Tanks Inc modified semi-narrowed tank with Waldron 255 pump and corvette filter/regulator. Initially the fuel pressure gauge I mounted at the end of the fuel rail read 60 and all was well. Then I noticed a squeal from the gas tank area when I turned off the car; restarted it and pressure was pegged over 100 on gauge. I added 5 gallons to the tank and fuel is now leaking out vent hose unless I unscrew cap. Even with cap off, fuel pressure stays high. Any ideas?
I replaced filter/regulator, put a loop and back flow in vent tube and blew out return line. Fixed it for about 5 minutes then started high pressure again.

[Danny Cabral]

http://dev.aeromotiveinc.com/frequently-asked-questions/faq-efi-regulators/ (Aeromotive EFI FPR FAQs - Read Question #8!)

[Palmettogasman]

Looks like it's time to re-do my return line and upgrade my regulator. Thanks a lot, greatly appreciated

[CarlC]

Something is not right. That regulator can easily handle a Walbro 255lph pump, and about a zillion GM cars used that arrangement with good results.

What size is your return line, and how is the venting done?