Ch. 82 Vehicle Emissions Standards & Testing
Questions with Correct Answers
Technician A says that high HC emission levels are often caused by a
fault in the ignition system. Technician B says that high CO2 emissions
are usually caused by a richer-than-normal air-fuel mixture. Which
technician is correct? Correct Answer-Technician A only
HC and CO are high and CO2 and O2 are low. This could be caused by
a Correct Answer-Rich mixture
Which gas is generally considered to be the rich indicator? (The higher
the level of this gas, the richer the air-fuel mixture.) Correct Answer-CO
Which gas is generally considered to be the lean indicator? (The higher
the level of this gas, the leaner the air-fuel mixture.) Correct Answer-O2
Which exhaust gas indicates efficiency? (The higher the level of this
gas, the more efficient the engine operates.) Correct Answer-CO2
All of the gases are measured in percentages except ____. Correct
Answer-HC
After the following emissions were measured, how was the engine
operating?
HC=766RPM CO2=8.2% CO=4.6% O2=0.1% Correct Answer-Too rich
, Technician A says that carbon inside the engine can cause excessive
NOx to form. Technician B says that excessive NOx could be caused by
a cooling system fault causing the engine to operate too hot. Which
technician is correct? Correct Answer-Both technicians A & B
A clogged EGR passage could cause excessive ____ exhaust emissions.
Correct Answer-NOx
An ignition fault could cause excessive ____ exhaust emissions. Correct
Answer-HC
Which of the following corresponds to ZEV standard? Correct Answer-a
vehicle producing no emissions from the tailpipe
Which of the following standards is twice as stringent as Tier 1
standards for HC and
NOx? Correct Answer-LEV
Which of the following emission standards is the most stringent? Correct
Answer-PZEV
Which of the following tests involves measuring tailpipe emissions of a
vehicle at 2500RPM? Correct Answer-one-speed idle test
Questions with Correct Answers
Technician A says that high HC emission levels are often caused by a
fault in the ignition system. Technician B says that high CO2 emissions
are usually caused by a richer-than-normal air-fuel mixture. Which
technician is correct? Correct Answer-Technician A only
HC and CO are high and CO2 and O2 are low. This could be caused by
a Correct Answer-Rich mixture
Which gas is generally considered to be the rich indicator? (The higher
the level of this gas, the richer the air-fuel mixture.) Correct Answer-CO
Which gas is generally considered to be the lean indicator? (The higher
the level of this gas, the leaner the air-fuel mixture.) Correct Answer-O2
Which exhaust gas indicates efficiency? (The higher the level of this
gas, the more efficient the engine operates.) Correct Answer-CO2
All of the gases are measured in percentages except ____. Correct
Answer-HC
After the following emissions were measured, how was the engine
operating?
HC=766RPM CO2=8.2% CO=4.6% O2=0.1% Correct Answer-Too rich
, Technician A says that carbon inside the engine can cause excessive
NOx to form. Technician B says that excessive NOx could be caused by
a cooling system fault causing the engine to operate too hot. Which
technician is correct? Correct Answer-Both technicians A & B
A clogged EGR passage could cause excessive ____ exhaust emissions.
Correct Answer-NOx
An ignition fault could cause excessive ____ exhaust emissions. Correct
Answer-HC
Which of the following corresponds to ZEV standard? Correct Answer-a
vehicle producing no emissions from the tailpipe
Which of the following standards is twice as stringent as Tier 1
standards for HC and
NOx? Correct Answer-LEV
Which of the following emission standards is the most stringent? Correct
Answer-PZEV
Which of the following tests involves measuring tailpipe emissions of a
vehicle at 2500RPM? Correct Answer-one-speed idle test
