Exam 7: Fuel System and Related Input Sensorsoutput Actuators Diagnosis

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?

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

Increasing injector pulse width has what effect on the air/fuel ratio?

What is the primary function of the fuel control system?

How does the PCM control the air/fuel ratio on fuel-injected engines?

A vehicle is brought in for a complaint of a rotten egg smell coming from the exhaust. The most likely cause is:

What does the term injection pulse width refer to?

The minimum idle speed adjustment procedure is the same for all years and makes of the vehicles.

The PCM makes what assumption regarding the availability of fuel at the injectors?

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

A vacuum leak may cause the engine idle speed to be lower than specified.

A stethoscope may be used to find a malfunctioning fuel injector.

Low supply voltage at the fuel pump may result in low fuel pump volume.

On a return-style fuel injection system, what could cause high fuel pressure, and what would the results be?

How should the PCM react if the oxygen sensor detects a low oxygen level in the exhaust stream?

How does the fuel system monitor treat one-trip and two-trip faults detected in the fuel delivery system?

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?

What is the first step that must be performed after attaching a fuel pressure gauge to a fuel system?

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