Exam 7: Fuel System and Related Input Sensors Output Actuators Diagnosis

The idle air control (AIC) motor controls idle speed under some but not all engine operating conditions.

What is the primary function of the fuel control system?

In a returnless fuel system, no unused fuel is returned to the gas tank.

What is one reason for the requirement of high system fuel pressures in port fuel-injected vehicles?

If a vehicle is not equipped with a mass air flow (MAF) sensor, how does the PCM determine the volume of the incoming air charge drawn into the combustion chamber?

Technician A says that the fuel system volume test can help to identify a restricted fuel filter. Technician B says that the fuel system pressure test is one of the first tests that should be performed during fuel system diagnosis. Who is correct?

Technician A says that an air leak between the MAF sensor and the throttle plate will cause the MAF sensor to indicate to the PCM that less air is entering the engine in relation to the throttle opening. Technician B says that an air leak between the MAF sensor and the throttle plate is considered an uncalibrated air leak. Who is correct?

What would the engine operational problem be on a vehicle with a defective fuel pump relay if the vehicle has an oil pressure switch wired in parallel to the fuel pump relay?

A rich air/fuel ratio may be caused by low fuel pump pressure.

The term electronic fuel injection (EFI) may properly be applied to:

The term injector pulse width refers to:

If the rpm signal is lost on an electronic fuel-injected vehicle, which of the following conditions will exist?

Technician A says that disconnecting the vehicle battery during diagnosis may erase the adaptive strategy from the PCM. Technician B says that a vacuum leak may be misdiagnosed as a fuel delivery problem. Who is correct?

How are SFI injectors controlled by the PCM?

The quantity or volume of fuel delivered to the cylinders by the fuel injectors is determined by:

During engine operation, the crankshaft position sensor identifies crankshaft position and:

What is the most likely cause of a customer complaint of a rotten egg odor?

How can after market exhaust system modifications reduce fuel efficiency and power?

What does the term injection pulse width refer to?

Why have many manufacturers integrated a returnless fuel system into their fuel system designs?