Help with fuel system

[school boy]

Ok I need a little help before I pull my hair out. Im doing a tpi swap and Im having return line issues. I have the dual tanks with the low pressure efi pumps from factory and an inline high pressure pump. Im was having return line leakage at some of the connector and after using a fuel pressure test gauge found out the fuel isn't returning. It builds pressure up to about 50 psi then rockets to 90 psi. I believe its the tank selector valve. Anybody else have any ideas?

[buddy_1]

Could be a fuel pressure regulator problem. Remove the return hose from the switching valve (eliminate the valve) and run it into a gas can. Then check pressure reading again. If it clears up the valve or one of the sender fittings is stopped up or restricted. If it doesn't clear up then it is the pressure regulator or the line to the switching valve.

[school boy]

The fuel pressure regulator on the rail is good and we're getting the high pressure after the regulator too. Is there a regulator in the selector valve too? btw, both tanks and everything in the tanks only have about 300-400 miles on them.

[buddy_1]

There isn't a regulator in the valve. Is the valve new or original?

[school boy]

valve was put in when the tanks were.