The system that stores fuel for present use and delivers it as needed to an engine; includes the fuel tank, fuel lines, pump, filter, vapor return lines, carburetor or injection components, and all fuel system vents and evaporative emission control systems or devices that provide fuel supply and fuel metering functions. Some early vehicles and other engines had a gravity-feed fuel system, in which fuel flowed to the engine from a tank located above it. Automotive and most other engines have a pressurized fuel system with a pump that draws or pushes fuel from the tank to the engine.