Question 1

What are some of the possible causes of spark knock?

Accepted Answer

The following are other possible causes of spark knock: 
1. If the engine knocks under load, check the base spark timing first. 
2. Check the cooling system temperature. A failed cooling fan switch, a stuck thermostat, or a restricted radiator can also cause pinging. 
3. Preignition can result from a loose spark plug or spark plugs of too high a heat range. 
4. Fuel of too low an octane for a high-compression engine can cause spark knock.

Question 2

All of the following statements are true EXCEPT:

Accepted Answer

A)  on a late-model car running at 2,000 rpm with a hot converter, normal readings from the exhaust pipe should be above 0.1% (with an air injection system disabled). 
B)  like HC, O2 is not formed during combustion so it should be consumed during each combustion cycle. 
C)  before combustion, the incoming air is 21% O2. 
D)  when checking O2 emissions in the exhaust, it is very important that there be no supplemental air or exhaust system leak. 
A)  on a late-model car running at 2,000 rpm with a hot converter, normal readings from the exhaust pipe should be above 0.1% (with an air injection system disabled). 
B)  like HC, O2 is not formed during combustion so it should be consumed during each combustion cycle. 
C)  before combustion, the incoming air is 21% O2. 
D)  when checking O2 emissions in the exhaust, it is very important that there be no supplemental air or exhaust system leak. A

Question 3

The tool MOST-Likely designed to reduce normal exhaust emissions is:

Accepted Answer

A)  pyrometer 
B)  catalytic converter 
C)  charcoal canister 
D)  thermistor 
A)  pyrometer 
B)  catalytic converter 
C)  charcoal canister 
D)  thermistor B

Question 4

How would you use a flowmeter to check for EVAP leaks?

Accepted Answer

On a warm engine, after 2 minutes at idl

Question 5

A running engine will always have at least ____ CO2.

Accepted Answer

A)  1% 
B)  2% 
C)  3% 
D)  4% 
A)  1% 
B)  2% 
C)  3% 
D)  4%

Question 6

A leaking EVAP system can allow gasoline vapors to escape into the air.

Accepted Answer

A) True 
 B)False

Question 7

How would you locate a leak in the crankcase ventilation system?

Accepted Answer

A smoke tester is the best way to check

Question 8

While having a discussion, Technician A says that when analyzing exhaust readings CO and O2 should be nearly equal. Technician B says that CO, O2, and HC should be low. Who is correct?

Accepted Answer

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

Question 9

A major cause of air pollution from motor vehicles is fuel ____________________.

Accepted Answer

The answer of A major cause of air pollution from...

Question 10

High EGR flow results in undercalculation of the fuel and a lean air-fuel mixture, and low EGR flow drives the mixture rich.

Accepted Answer

A) True 
 B)False

Question 11

CO is oxidized into CO2 by the catalytic converter and ____________________ system.

Accepted Answer

Question 12

____ are caused by gasket failures that prevent the ventilation system from operating as designed.

Accepted Answer

A)  Evaporative leaks 
B)  Oil leaks 
C)  Vacuum hose leaks 
D)  Manifold leaks 
A)  Evaporative leaks 
B)  Oil leaks 
C)  Vacuum hose leaks 
D)  Manifold leaks

Question 13

While having a discussion, Technician A says that driving the car on the road or on a dyno is the best way to heat up the cat. Technician B says that it is best to run the engine in a stall. Who is correct?

Accepted Answer

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

Question 14

The ____________________ analyzer measures the content of gases in the exhaust through a probe installed in the exhaust pipe of a running engine.

Accepted Answer

The answer of The ____________________ analyzer measures the content of...

Question 15

What are the steps involved in testing the PCV valve?

Accepted Answer

To test the PCV valve: 
PCV valves can b

Question 16

Vacuum problems can be caused by incorrect hose routing or defects with a backpressure transducer, thermal switching valve, or solenoid.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is LEAST-Likely a typical symptom for EGR system problems?

Accepted Answer

A)  Hesitation when cold 
B)  Detonation 
C)  Increased cooling system temperature 
D)  Converter light off 
A)  Hesitation when cold 
B)  Detonation 
C)  Increased cooling system temperature 
D)  Converter light off

Question 18

All of the following statements are true EXCEPT:

Accepted Answer

A)  when intake or exhaust is restricted the engine cannot bring in enough fresh air and fuel. 
B)  one cause of an air-fuel mixture that is too lean to burn is a leak in the intake system. 
C)  after a misfire, whatever remains in the cylinder ends up in the exhaust stream, decreasing the HC level. 
D)  high HC can be caused by a defective spark plug or problems with ignition wiring. 
A)  when intake or exhaust is restricted the engine cannot bring in enough fresh air and fuel. 
B)  one cause of an air-fuel mixture that is too lean to burn is a leak in the intake system. 
C)  after a misfire, whatever remains in the cylinder ends up in the exhaust stream, decreasing the HC level. 
D)  high HC can be caused by a defective spark plug or problems with ignition wiring.

Question 19

High HC is caused by an excessive amount of unburned ____________________.

Accepted Answer

The answer of High HC is caused by an excessive...

Question 20

The measurement 1 ppm means that out of every thousand parts of an exhaust sample, one part is HC.

Accepted Answer

A) True 
 B)False

Exam 44: Emission Control System Service

What are some of the possible causes of spark knock?

All of the following statements are true EXCEPT:

The tool MOST-Likely designed to reduce normal exhaust emissions is:

How would you use a flowmeter to check for EVAP leaks?

A running engine will always have at least ____ CO2.

A leaking EVAP system can allow gasoline vapors to escape into the air.

How would you locate a leak in the crankcase ventilation system?

While having a discussion, Technician A says that when analyzing exhaust readings CO and O2 should be nearly equal. Technician B says that CO, O2, and HC should be low. Who is correct?

A major cause of air pollution from motor vehicles is fuel ____________________.

High EGR flow results in undercalculation of the fuel and a lean air-fuel mixture, and low EGR flow drives the mixture rich.

CO is oxidized into CO2 by the catalytic converter and ____________________ system.

____ are caused by gasket failures that prevent the ventilation system from operating as designed.

While having a discussion, Technician A says that driving the car on the road or on a dyno is the best way to heat up the cat. Technician B says that it is best to run the engine in a stall. Who is correct?

The ____________________ analyzer measures the content of gases in the exhaust through a probe installed in the exhaust pipe of a running engine.

What are the steps involved in testing the PCV valve?

Vacuum problems can be caused by incorrect hose routing or defects with a backpressure transducer, thermal switching valve, or solenoid.

Which of the following is LEAST-Likely a typical symptom for EGR system problems?

All of the following statements are true EXCEPT:

High HC is caused by an excessive amount of unburned ____________________.

The measurement 1 ppm means that out of every thousand parts of an exhaust sample, one part is HC.

Introduction to the Automobile

Automotive Careers and Technician Certification

Shop Safety

Shop Management, Service Records, and Parts

Locating Service Information and Specifications

Measuring Tools and Systems

Hardware, Fasteners, Drills, and Thread Repair

Shop Tools

General Shop Equipment

Cleaning Equipment and Methods

Lifting Equipment and Air Compressors

Engine Lubrication

Underhood and Body Inspection Car on Ground

Undercar Inspection and Service

Introduction to the Engine

Engine Classifications and Advanced Transportation Technologies

Engine Size and Measurements

Engine Upper End

Engine Lower End and Lubrication System Theory

Cooling System Theory

Cooling System Service

Automotive Belts

Automotive Hoses

Automotive Plumbing: Tubing and Pipe

Basic Electrical System Theory and Repairs

Battery Fundamentals

Battery Service

Starting System Fundamentals

Starting System Service

Charging System Fundamentals

Charging System Service

Lighting and Wiring Fundamentals

Lighting and Wiring Service

Safety, Security, Comfort Systems, and Electrical Accessories

Heating and Air Conditioning Fundamentals

Heating and Air Conditioning Service

Ignition System Fundamentals

Ignition System Service

Fuels and Alternative Fuels

Fuel System Fundamentals

Fuel System Service

Intake and Exhaust Systems, Turbochargers and Superchargers

Emission Control System Fundamentals

Electronics and Computer Systems Fundamentals

Electronics and Computer Systems Service

Advanced Emissions and On-Board Diagnostics Odb

Diagnosing Engine Performance Problems

Diagnosing Engine Mechanical Problems

Engine Removal and Disassembly

Engine Sealing, Gaskets, Fastener Torque

Engine Diagnosis and Service: Cylinder Head and Valvetrain

Engine Diagnosis and Service: Block, Crankshaft, Bearings, and Lubrication System

Engine Diagnosis and Service: Piston, Piston Rings, Connecting Rod, Engine Balancing

Ordering Parts, Short and Long Blocks, Engine Assembly

Engine Installation, Break In, and In-Chassis Repairs

Brake Fundamentals

Brakes Service

Anti-Lock Brakes Traction and Stability Control

Bearings, Seals, and Greases

A running engine will always have at least ____ CO₂.

While having a discussion, Technician A says that when analyzing exhaust readings CO and O₂ should be nearly equal. Technician B says that CO, O₂, and HC should be low. Who is correct?

CO is oxidized into CO₂ by the catalytic converter and ____________________ system.