While discussing PFI systems, Technician A says the PCM provides the proper air/fuel ratio by controlling the fuel pressure. Technician B says the PCM provides the proper air/fuel ratio by controlling the injector pulse width. Who is correct?

Question

Quizplus · Accepted Answer

Technician B is correct because in Port Fuel Injection (PFI) systems, the PCM (Powertrain Control Module) controls the air/fuel ratio by adjusting the injector pulse width, which is the amount of time the fuel injector is open and thus how much fuel is injected into the engine. The fuel pressure in these systems is typically constant, and it's the duration of the injector opening that is varied to control the fuel delivery.

While Discussing PFI Systems, Technician a Says the PCM Provides