how fuel injection works

Electronic fuel injection or EFI is a way of controlling the amount of fuel being used by the engine in all types of conditions. Mechanical fuel injection was an earlier version used by spark ignited engines. Mechanical injection is still used on diesel engines often. Most spark ignited engines use electronic fuel injecton due to the adjustability and precision of the electronics involved. The sensors send all different types of information back to the ecu (computer) then it computes from a internal map what the value should at that paticular point. The map, as it’s called, is just a huge directory of numeric values. These values tell the injectors when and how long to stay open. The longer they stay open the more fuel gets sprayed into the engine. The fuel pressure can affect the overall map by shifting it up or down.