Question 1

Explain why a small PCV valve opening is adequate at idle speed.

Accepted Answer

Because the engine is not under heavy load, the amount of blowby gas is minimal and 
the small valve opening is all that is needed.

Question 2

Technician A says high engine temperatures reduce HC and CO emissions. Technician B says incorrect ignition timing can increase the production of NO X .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 C

Question 3

The PCV system prevents ____________________ gases from escaping to the atmosphere.

Accepted Answer

blowby,crankcase

Question 4

Which of the following is NOT part of an enhanced (OBD-II)evaporative control system?

Accepted Answer

A) thermal vacuum valve (TVV) 
B) canister vent solenoid valve 
C) fuel tank vacuum or pressure sensor 
D) canister purge solenoid valve 
A) thermal vacuum valve (TVV) 
B) canister vent solenoid valve 
C) fuel tank vacuum or pressure sensor 
D) canister purge solenoid valve

Question 5

The two factors that have the greatest effect on vehicle emissions are air/fuel ratio and ___________________ at different spots within the combustion chamber.

Accepted Answer

The answer of The two factors that have the greatest...

Question 6

Technician A says oil in the PCV filter and air cleaner can occur if the PCV valve is restricted or plugged. Technician B says oil buildup inside the throttle body can be an indication of high crankcase pressure. 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 7

Technician A says a three-way catalytic converter (TWC)oxidizes carbon monoxide and hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NO x into nitrogen and carbon dioxide. 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 8

EGR flow is disabled during throttle openings greater than ___________________ percent

Accepted Answer

The answer of EGR flow is disabled during throttle openings...

Question 9

A digital EGR valve contains up to three electric solenoids that are operated directly by the PCM.

Accepted Answer

A) True 
 B)False

Question 10

How is acid rain related to automotive emissions?

Accepted Answer

When NO _x in the atmosphere mix

Question 11

The first controlled automotive emission was ______.

Accepted Answer

A) crankcase vapors 
B) tailpipe emissions (HC and CO) 
C) NO X 
D) evaporative emissions 
A) crankcase vapors 
B) tailpipe emissions (HC and CO) 
C) NO X 
D) evaporative emissions

Question 12

OBD-II systems monitor the EVAP system for leaks.

Accepted Answer

A) True 
 B)False

Question 13

Most current light-duty diesel engines use a ___________________ rail injection system.

Accepted Answer

The answer of Most current light-duty diesel engines use a...

Question 14

An I/M 240 test lasts _____ minutes.

Accepted Answer

A) two 
B) four 
C) six 
D) eight 
A) two 
B) four 
C) six 
D) eight

Question 15

Heated air inlet systems, manifold heat control valves (heat risers), and EFE heater grids were used on older cars with carburetors and TBI fuel injection to prevent vaporized fuel from condensing inside the ____________________.

Accepted Answer

The answer of Heated air inlet systems, manifold heat control...

Question 16

Under what conditions is the EGR valve open?

Accepted Answer

A) starting 
B) idle (warm engine) 
C) cruise (warm engine) 
D) Wide open throttle 
A) starting 
B) idle (warm engine) 
C) cruise (warm engine) 
D) Wide open throttle

Question 17

A three-way catalytic converter (TWC)stores oxygen when the air/fuel ratio is rich.

Accepted Answer

A) True 
 B)False

Question 18

NO X , HC, and CO are changed into harmless gases by the ____________________ in the three way catalytic converter.

Accepted Answer

Question 19

Where does a secondary air injection system deliver its air supply when the engine is cold and at operating temperature?

Accepted Answer

When the engine is cold, it de

Question 20

An ignition misfire can cause excessive carbon monoxide emissions in the exhaust.

Accepted Answer

A) True 
 B)False

Exam 33: Emission Control Systems

Explain why a small PCV valve opening is adequate at idle speed.

Technician A says high engine temperatures reduce HC and CO emissions. Technician B says incorrect ignition timing can increase the production of NO X .Who is correct?

The PCV system prevents ____________________ gases from escaping to the atmosphere.

Which of the following is NOT part of an enhanced (OBD-II)evaporative control system?

The two factors that have the greatest effect on vehicle emissions are air/fuel ratio and ___________________ at different spots within the combustion chamber.

Technician A says oil in the PCV filter and air cleaner can occur if the PCV valve is restricted or plugged. Technician B says oil buildup inside the throttle body can be an indication of high crankcase pressure. Who is correct?

Technician A says a three-way catalytic converter (TWC)oxidizes carbon monoxide and hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NO x into nitrogen and carbon dioxide. Who is correct?

EGR flow is disabled during throttle openings greater than ___________________ percent

A digital EGR valve contains up to three electric solenoids that are operated directly by the PCM.

How is acid rain related to automotive emissions?

The first controlled automotive emission was ______.

OBD-II systems monitor the EVAP system for leaks.

Most current light-duty diesel engines use a ___________________ rail injection system.

An I/M 240 test lasts _____ minutes.

Heated air inlet systems, manifold heat control valves (heat risers), and EFE heater grids were used on older cars with carburetors and TBI fuel injection to prevent vaporized fuel from condensing inside the ____________________.

Under what conditions is the EGR valve open?

A three-way catalytic converter (TWC)stores oxygen when the air/fuel ratio is rich.

NO X , HC, and CO are changed into harmless gases by the ____________________ in the three way catalytic converter.

Where does a secondary air injection system deliver its air supply when the engine is cold and at operating temperature?

An ignition misfire can cause excessive carbon monoxide emissions in the exhaust.

Careers in the Automotive Industry

Workplace Skills

Basic Theories and Math

Automotive Systems

Hand Tools and Shop Equipment

Diagnostic Equipment and Special Tools

Working Safely in the Shop

Preventative Maintenance and Basic Services

Automotive Engine Designs and Diagnosis

Engine Disassembly and Cleaning

Lower-End Theory and Service

Upper-End Theory and Service

Engine Sealing and Reassembly

Lubricating and Cooling Systems

Basics of Electrical Systems

General Electrical System Diagnostics and Service

Batteries: Theory, Diagnosis, and Service

Starting and Motor Systems

Charging Systems

Lighting Systems

Instrumentation and Information Displays

Basics of Electronics and Computer Systems

Electrical Accessories

Engine Performance Systems

Detailed Diagnosis and Sensors

Ignition Systems

Ignition System Diagnosis and Service

Gasoline, Diesel and Other Fuels

Fuel Delivery Systems

Electronic Fuel Injection

Fuel Injection Diagnosis and Service

Intake and Exhaust Systems

Emission Control Diagnosis and Service

Hybrid Vehicles

Electric Vehicles

Clutches

Manual Transmissions and Transaxles

Manual Transmission and Transaxle Service

Drive Axles and Differentials

Automatic Transmissions and Transaxles

Electronic Automatic Transmissions

Automatic Transmission and Transaxle Service

Four- and All-Wheel Drive

Tires and Wheels

Suspension Systems

Steering Systems

Restraint Systems: Theory, Diagnosis, and Service

Wheel Alignment

Brake Systems

Drum Brakes

Disc Brakes

Antilock Brake, Traction Control, and Stability Control Systems

Heating and Air Conditioning

Heating and Air Conditioning Diagnosis and Service

Filters

Technician A says high engine temperatures reduce HC and CO emissions. Technician B says incorrect ignition timing can increase the production of NO _X .Who is correct?

Technician A says a three-way catalytic converter (TWC)oxidizes carbon monoxide and hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NO _x into nitrogen and carbon dioxide. Who is correct?

NO _X , HC, and CO are changed into harmless gases by the ____________________ in the three way catalytic converter.