DESCRIPTION
Evaporative Emission Control System prevents fuel vapor stored in fuel tank from draining into the atmosphere.
Scheme 9
When the fuel evaporates in the fuel tank, the vapor passes through vent hoses or tubes to EVAP. canister filled with charcoal and the EVAP. canister temporarily holds it with charcoal. If ECM wants to draw the gathered vapor into the combustion chambers during certain operating conditions, it will make vacuum in intake manifold to move it.
A ratchet tightening device on the threaded fuel filler cap reduces the chances of incorrect installation, which would seal the fuel filler. After the gasket on the fuel filler cap and the filler neck flange contact each other, the ratchet produces a loud clicking noise indicating the seal has been set.
