Deck 22: Fuel-Injection Components and Operation

Question 1

The injectors on an EFI equipped engine are opened using ________ to lift the spray needle.

A) oil pressure
B) a solenoid
C) a cam
D) engine vacuum

Answer 1

B

Question 2

Technician A says that most fuel injection systems use the PCM to control the pulsing of the fuel injectors. Technician B says that most fuel injection systems use the PCM to control the operation of the fuel pump relay. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Answer 2

C

Question 3

All of the following statements are correct EXCEPT ________.

A) dirt and water are more likely to contaminate the injectors if the fuel level is low
B) O-rings seal the injector to keep fuel away from the windings
C) fuel cools the injector
D) fuel makes contact with the injector windings

Answer 3

D

Question 4

Which statement is correct?

A) Throttle body injectors inject fuel below the throttle plate.
B) Dirt is most likely to be found near the bottom of the fuel tank.
C) Dirt is most likely to float on top of the fuel.
D) Port fuel injectors inject fuel above the throttle plate.

Question 5

All these methods can calculate airflow EXCEPT ________.

A) load calculation
B) speed density
C) mass airflow
D) All of these are methods of calculating the air-fuel mixture.

Question 6

Which sensor is used to calculate the amount of fuel required using the speed density method?

A) ECT and IAT sensors
B) TP sensor
C) MAP sensor
D) All of these are used

Question 7

Technician A says that all port fuel injected systems use the speed density method. Technician B says that throttle body injection systems use the speed density method. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 8

Which term is used to describe pulses of air flowing from the engine out the air intake due to the time interval between intake events with a four-cylinder engine?

A) Reverse airflow
B) Pressure reaction
C) Speed density
D) Intake redirection

Question 9

Which term is used to describe a TBI system where the injector pulses once per each distributor reference pulse?

A) Synchronized
B) Mass airflow
C) Speed density
D) Nonsynchronized

Question 10

Which of these describes a condition that results in more fuel being delivered?

A) Short pulse width
B) Long pulse width
C) Hot intake air
D) Warm engine

Question 11

Which of these is true regarding port fuel injection systems?

A) Fuel is injected almost directly into the combustion chamber.
B) Fuel distribution to all cylinders is equal.
C) The intake manifold may be shaped and sized to best fit the engine performance requirements.
D) All of these are correct.

Question 12

Which type of port fuel injection groups the injectors into two groups, with each group firing once per crankshaft revolution?

A) Throttle body injection
B) Grouped double fired
C) Sequential fired
D) Simultaneous double fired

Question 13

A sequential fuel injection system uses a ________ to time the fuel injection pulses.

A) CMP sensor
B) throttle body sensor
C) MAP sensor
D) Spark sensor

Question 14

Which type of port fuel injection fires each injector separately, following the engine firing order?

A) Sequential fired
B) Grouped double fire
C) Throttle body injection
D) Simultaneous double fired

Question 15

Which type of port fuel injection allows mixture adjustments between the firing of each cylinder?

A) Simultaneous
B) Throttle body
C) Sequential
D) Grouped

Question 16

Technician A says that all injectors in a sequential fuel injection system often use the same power wire. Technician B says that each injector in a sequential fuel injection system should have a different ground wire. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 17

Technician A says that fuel pressure regulators are often located on the return side of the fuel rail. Technician B says that the fuel pressure regulator is located at the fuel tank on vehicles using mechanical returnless systems. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 18

Technician A says that vacuum-operated fuel pressure regulators allow an equal pressure drop across the fuel injectors all the time. Technician B says that intake manifold pressure is high at idle. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 19

Technician A says that vehicles with electronic returnless fuel systems use pulse width modulation to power the fuel pump and maintain fuel pressure. Technician B says that the electronic returnless fuel system uses a contact switch to control the fuel pump. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 20

All these are returnless fuel systems EXCEPT ________.

A) Mechanical returnless fuel system
B) Electronic returnless fuel system
C) Demand delivery system
D) All of these are types of returnless systems.

Question 21

Which term describes the PCM shutting off fuel injection when the accelerator is pressed all the way down?

A) Starting mode
B) Open loop mode
C) Closed loop mode
D) Clear flood mode

Question 22

Which term describes the PCM using oxygen sensor feedback to control fuel delivery?

A) Starting mode
B) Open loop mode
C) Closed loop mode
D) Clear flood mode

Question 23

Technician A says that an idle air control valve controls the airflow past the fuel injectors. Technician B says that the idle air control valve is usually controlled by a stepper motor. Which technician is correct?

A) Technician A only
B) Technician B only
C) Both technicians A and B
D) Neither technician A nor B

Question 24

The fuel injector in a central port fuel injection system is called a(an) ________.

A) injector tube
B) injector element
C) poppet nozzle
D) linear tip