I want to relieve the fuel pressure on my '93 dual tank F-150 before disconnecting the two fuel lines from the back tank to replace it. The shop manual I have says the pressure relief valve is located in the "upper right hand side of the engine compartment". But it isn't! Does anyone know where the valve is and what it looks like so I can locate it and move forward with replacing the leaking rear fuel tank safely?

 

It's the fuel pressure test port (schreder valve) located on the fuel rail up front and a little left of center ( driver's side) on the the engine. But a better way would be to either trip the fuel intertia cut off switch (above and a little left of brake pedal) or pull the fuel pump relay then crank the engine over for a few seconds. This is a common practice when changing the furl filter.

Mike

 

The fuel pressure relief valve looks sorta like a tire schrader valve, and it's on the fuel rail - the chrome plated hard line that the injectors are connected to. Sometimes they are tough to find, or get to. You can also remove the fuel pump fuse and crank the truck a few times to bleed off residual pressure. Or whack the inertia switch with the end of a screwdriver handle while the truck is running, that works too. Wrap a heavy cloth around the fitting as you take it apart. It helps to keep fuel out of your eyes! Hoo - you'll only ever do that once....don't ask me how I know.

 

..don't do it w/ a lit cigarette either... ..thank god that eyebrow grew back..........