D 350 Pickup L6-359 5.9L DSL (1989)
Fillpipe Restrictor: Description and Operation
FUEL HOSES AND CLAMPS
The hoses used on fuel injected models are of a special type and only hoses marked EFI/EFM may be used as replacements. The clamps used are of a
rolled edge construction to prevent cutting hoses, and all replacements must be of this type.
PRESSURE/VACUUM FILLER CAP
The loss of liquid fuel or vapor is prevented by using a filler cap which releases under 10.9 to 13.45 kPa (1.58 to 1.95 psi). Only caps with these
specifications may be used as replacements to maintain the integrity of the fuel system.
ROLL-OVER VALVE
All fuel tanks of the closed type use a roll-over valve mounted on the top of the fuel tank. In addition to the roll-over valve there is a one way check
valve mounted on the fuel return line, in the tank, which prevents fuel from backing up into the return line from the tank. Under loss of fuel pressure
conditions, or conditions such as roll-over where tank pressure may exceed fuel return pressure, the check valve closes, preventing fuel loss from tank.
