The purpose of a fuel injector is to deliver precise amounts of fuel into the engine cylinder at the right time. Fuel injectors are electronically controlled valves that receive signals from the engine's computer and open and close to control the amount of fuel that is sprayed into the combustion chamber. This controlled spray of fuel ensures that the engine receives the exact amount of fuel it needs for optimal performance and fuel efficiency. Without fuel injectors, the engine would not be able to accurately control the amount of fuel it receives, which could result in reduced performance, decreased fuel efficiency, and potential engine damage.