injection involves spraying or injecting fuel directly into the engine's intake
manifold. Fuel injection, especially when it is electronically controlled, has
several major advantages over carbureted systems. These include improved driveability under all conditions, improved fuel control and economy, decreased
exhaust emissions, and an increase in engine efficiency and power.
Although fuel injection technology has been around since the 1920s, it wasn't
until the 1980s that manufacturers began to replace carburetors with electronic
fuel injection (EFI) systems. Many of the early EFI systems were throttle body
injection (TBI) systems in which the fuel was injected above the throttle plate.
Engines equipped with TBI have gradually become equipped with port fuel
injection (PFI), which had injectors located in the intake ports of the
cylinders. Since the 1995 model year, all new cars are equipped with EFI
Diesel engines, for quite some time, have been equipped with fuel injection
systems. The two basic differences between gasoline injection and diesel
injection are: diesel fuel is injected directly into the cylinders, and diesel
fuel injection systems are operated mechanically rather than electronically.
Although late-model diesel systems use electronic fuel controls, the fuel
injection system is a mechanical system that is controlled mechanically.