Multi-point fuel injection, or MPFI, is a gasoline delivery system that uses four individual fuel injectors to evenly disperse gas into an engine´s combustion chambers. MPFI was developed to succeed the older single-point fuel injection systems.
Single-point injection systems relied on an intake or carburetor to mix an approximate amount of fuel required to run the engine. This approach lead to many problems, such as having the engine run too rich or too lean. The MPFI system was produced to change that approach and increase the engines performance.
Multi-point fuel injection
MPFI, also called port injection, uses intake runners, which are essentially small tubes that connect from the intake manifold to the combustion chambers. Each fuel injector connects to an individual runner and injects gas into the engine, which allows for accurate fuel distribution. This type of fuel injection is found on most vehicles in use today.
Many late model vehicles are now replacing port injection with an upgraded system known as direct-point injection. Direct-point uses a similar method of injecting fuel into each individual cylinder with the only difference being its close proximity to the engine. Direct-port injection systems place the fuel injectors inside the combustion chambers. This improves the timing and fuel consumption of the vehicle.