Technician A says the vacuum hose on the fuel pressure regulator of a PFI system is connected to the intake manifold. Technician B says the fuel pressure regulator of a TBI injection system doesn't need a vacuum hose to regulate pressure because the injectors are located above the throttle plate where the air pressure is constant. Who is correct?

Question

Quizplus · Accepted Answer

Technician A is correct because in a Port Fuel Injection (PFI) system, the fuel pressure regulator's vacuum hose is indeed connected to the intake manifold to adjust fuel pressure based on engine load and vacuum. Technician B is also correct because in a Throttle Body Injection (TBI) system, the fuel pressure regulator doesn't require a vacuum hose since the fuel injectors are located above the throttle plate, where the pressure remains relatively constant regardless of engine load.

Technician a Says the Vacuum Hose on the Fuel Pressure