Prelude L4-1958cc DOHC (1989)
Fuel Return Line: Description and Operation
Fuel And Vapor System Components
This system utilizes three sets of fuel lines located underneath the vehicle on the left side.
FUEL FEED (SUPPLY) LINE
The Fuel Feed (Supply) Line delivers pressurized fuel from the fuel tank via the in-tank electric fuel pump. The fuel is fed into the fuel filter, from
there to the fuel rail.
FUEL RETURN LINE
This line is connected between the fuel pressure regulator and the fuel tank. When the fuel rail pressure exceeds the specified amount, the pressure
regulator opens and bleeds the excess fuel through this line and back into the fuel tank.
FUEL VAPOR LINE
This line is connected between the fuel tank and the charcoal canister for the evaporative emission controls. The Fuel Vapor Line is connected to the
fuel cut-off valve at the top of the fuel tank, a fuel/vapor separator line, and a two-way valve. The fuel cut-off valve and the fuel/vapor separator line
prevent liquid fuel from reaching the two-way valve. When the vapor pressure in the fuel tank exceed the specified value of the two-way valve, the
two-way valve opens and purges the vapors to the charcoal canister. For a more complete description of this system, see "EMISSION CONTROLS".
