Port injectors are positioned outside the combustion chamber – between the Mass Air Flow (MAF) Sensor and the intake valve, with the tip of the injector sitting outside, pointing towards the combustion chamber. With port fuel injectors, the air and fuel are combined outside the combustion chamber, in the intake manifold. From there the mixture flows through the intake tract and the intake valve to the combustion chamber.
Compared with high-pressure systems, the low-pressure system is less complex and more affordable. Thanks to its robust combustion process, gasoline port fuel injection also tolerates lower-quality fuel. The system’s maintenance-friendly design also reduces the overhead for system diagnostics.