Fuel tank pressure regulator

A tank venting system comprising

• a base formed to include a tank passageway adapted to be coupled in fluid communication to a fuel tank, a canister passageway adapted to be coupled in fluid communication to a fuel vapor recovery canister, a first fluid-flow chamber arranged to interconnect the tank and canister passageways in fluid communication, and a separate second fluid-flow chamber arranged to interconnect the tank and canister passageways in fluid communication,
• a single-stage valve arranged to regulate flow of fuel vapor between the tank and canister passageways through the first fluid-flow chamber, and
• a multi-stage valve arranged to regulate flow of fuel vapor between the tank and canister passageways through the second fluid-flow chamber,
• wherein the multi-stage valve comprises a coiled return spring, a small O-ring seal, a plunger, a plunger-receiver cage, a diaphragm seal associated with the plunger-receiver cage and formed to include a small-diameter vent aperture, and a coiled cage-biasing spring associated with an upwardly facing annular valve seat formed in the base.