Technician A says the fuel pressure regulator in a PFI system senses manifold vacuum and continually adjusts the fuel pressure to maintain a constant pressure drop across the injector. Technician B says the pressure regulator in a PFI system is designed to provide a constant pressure to the fuel injector throughout the range of engine loads and speeds. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Question

Technician A says the fuel pressure regulator in a PFI system senses manifold vacuum and  continually adjusts the fuel pressure to maintain a constant pressure drop across the injector. Technician B says the pressure regulator in a PFI system is designed to provide a constant pressure to the fuel injector throughout the range of engine loads and speeds. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Quizplus · Accepted Answer

Technician A is correct because in a Port Fuel Injection (PFI) system, the fuel pressure regulator does indeed sense manifold vacuum and adjusts the fuel pressure to maintain a constant pressure drop across the injector. Technician B's statement is incorrect as the pressure is not constant but varies with manifold vacuum to maintain the pressure differential.

Technician a Says the Fuel Pressure Regulator in a PFI