Deck 40: Fuel System Fundamentals

Question 1

10)While having a discussion, Technician A says that a coolant position sensor attached to the throttle body on the air inlet senses how many degrees the throttle plate is open. Technician B says that an air charge temperature sensor senses how many degrees the throttle plate is open. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Answer 1

D

Question 2

14)The term MOST-Likely used to describe the ratio of the engine's actual air-fuel mixture in the exhaust to what would be an ideal, or stoichiometric, mixture is:

A) alpha
B) beta
C) gamma
D) lambda

Answer 2

D

Question 3

6)Which of the following is LEAST-Likely to be included in a fuel tank cluster assembly?

A) Fuel pickup tube
B) Fuel pump
C) Fuel gauge sending unit
D) Pressure regulator

Answer 3

D

Question 4

3)With a carburetor, airflow through the engine is changed by opening the vacuum gauge.

Question 5

9)A(n) ____ measures the volume of air entering the engine.

A) airflow sensor
B) speed density sensor
C) hot wire MAF sensor
D) heated resistor MAF sensor

Question 6

8)The mechanical fuel injection systems found on some imported cars are called ____.

A) actuators
B) continuous fuel injection
C) power valves
D) closed loops

Question 7

7)All of the following statements are true EXCEPT:

A) electric fuel pumps on modern vehicles are computer controlled.
B) fuel filters can be located in a fuel line or in the tank.
C) fuel filters that are installed on the outlet side of a fuel pump are called outlet filters.
D) fuel injection systems require small, heavy-duty filters.

Question 8

12)All of the following statements are true EXCEPT:

A) engines with computer feedback have a sensor located in the exhaust manifold called an oxygen sensor .
B) in a feedback fuel system, the computer acts to make corrective changes to the air-fuel mixture entering the engine's cylinders.
C) actuators relay information to the computer about throttle position, air and coolant temperature, airflow, manifold pressure, and barometric pressure, among others.
D) feedback carburetors were used on some older cars.

Question 9

11)Which of the following is LEAST-Likely a component of an automobile computer system?

A) Computer
B) Sensor
C) Monitor
D) Actuator

Question 10

20)A(n) ____________________ controls the system's maximum amount of pressure.

Question 11

5)Modern diesel engines have been mandated to have exhaust emissions that are nearly free of particulates.

Question 12

1)When an older car has a cloth-type filter, this is called an in-tank filter.

Question 13

18)____________________ injection systems are those in which fuel is injected into the intake port at a precise point in relation to crankshaft and piston position.

Question 14

15)While having a discussion, Technician A says that GDI has the ability to run the engine with a variable air-fuel mixture that can be extremely lean with an overall average ratio of around 40:1. Technician B says that this can increase fuel economy by as much as 30%. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 15

4)Manifold pressure, temperature and density of the air, and engine speed are all considered by the computer before it calculates the correct amount of fuel to inject into the cylinders.

Question 16

13)The term MOST-Likely used to describe an event that occurs when the engine reaches operating temperature and the computer starts acting on information received from the O₂ sensor is:

A) closed loop fuel control
B) open loop fuel control
C) ground fuel control
D) filter fuel control

Question 17

19)The length of time that an injector remains open is called its ____________________.

Question 18

16)____________________ is the name of the process by which fuel is suspended in air in a mist of tiny droplets.

Question 19

17)____________________ occurs when atomized fuel turns into a gas (vapor).

Question 20

2)Carburetors are old technology. The carburetor's job is to atomize air and fuel in the proper proportion.

Question 21

24)What does the term returnless mean, as in returnless fuel systems?

Question 22

23)What are the characteristics of a returnless fuel system?

Question 23

25)What is the difference between a heated resistor MAF sensor and a hot wire MAF sensor?

Question 24

22)Compared to throttle-body injection (TBI) systems, what are the advantages of port fuel injection systems?

Question 25

21)How do the following circuits in a carburetor work: float circuit and choke?