Prelude L4-2056cc DOHC (1990)
Fuel Tank Pressure Release Valve: Description and Operation
Fuel And Vapor System Components
The Two-way Valve, mounted on top of the fuel tank, vents fuel tank vapor pressure into the charcoal canister. When fuel tank pressure exceeds 0.4 to
1.4 in. Hg. (10 to 35 mmHg) the Two-way Valve opens. Once open, the fuel tank vapors are bled off into the charcoal canister until pressure drops
below 0.4 to 1.4 in. Hg. The ECU then determines when to draw the vapors from the canister into a port on the throttle body. For a more complete
explanation, see "EMISSION CONTROLS".
