Emission Control MCQ Test

1. The illuminated malfunction indicator lamp (MIL) lets the tech know that there is an emission problem that needs to be diagnosed.

True

False

The check engine light or malfunction indicator lamp is responsible for notifying the driver of a concern with emission regulation equipment.

Explanation

The check engine light or malfunction indicator lamp is responsible for notifying the driver of a concern with emission regulation equipment.

2. Emissions can be caused naturally by:

Forest fires.

Volcanoes.

Decomposition of materials.

All of the above

Emissions are a product of combustion. Combustion is naturally occurring and so are instances that aren't man-made.

Explanation

Emissions are a product of combustion. Combustion is naturally occurring and so are instances that aren't man-made.

3. A limit value is the maximum amount of _____________ that a vehicle is permitted to emit.

Speed

Emissions

Air

Water

There is a limit on how much of each harmful gas a vehicle can emit.

Explanation

There is a limit on how much of each harmful gas a vehicle can emit.

4. What does the Environmental Protection Agency (EPA) require all vehicles to have to warn the driver of an emission fault?

A beeping horn

An illuminated light

A buzzing buzzer

A ringing bell

A light MUST BE in every vehicle that has OBD II.

Explanation

A light MUST BE in every vehicle that has OBD II.

5. Today's emissions come from the vehicle's:

Fuel system.

Crankcase.

Tailpipe.

All of the above

Unwanted vehicle emissions are created from all of the above.

Explanation

Unwanted vehicle emissions are created from all of the above.

6. In automotive applications, most_______________ is/are a by-product of combustion and is/are emitted from the exhaust system.

Fuel

Air

Emissions

Catalysts

Most emissions created from cars is from the tailpipe.

Explanation

Most emissions created from cars is from the tailpipe.

7. The main concern of the evaporative emission (EVAP) system is the gas cap.

True

False

Yes, the fuel filler cap is by far the most overlooked component of the EVAP emissions system, by both customers and technicians.

Explanation

Yes, the fuel filler cap is by far the most overlooked component of the EVAP emissions system, by both customers and technicians.

8. Tech A says that carbon monoxide is lethal. Tech B says never to run an engine inside a closed shop without proper exhaust ventilation. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

CO will kill you. An engine running in an unventelated shop will harbor this deadly gas.

Explanation

CO will kill you. An engine running in an unventelated shop will harbor this deadly gas.

9. The stoichiometric ratio also referred to as lambda, is the ratio of air to fuel at which all of the oxygen in the air and all the fuel are completely burned. The stoichiometric ratio for gasoline is:

34.3:1.

17.2:1.

15.7:1.

14.7:1.

14.7:1 is the sweet spot for engine performance and emissions.

Explanation

14.7:1 is the sweet spot for engine performance and emissions.

10. ______________ is a colorless, odorless, tasteless, flammable, and highly toxic gas.

Carbon dioxide

Hydrocarbons

Carbon monoxide

Sulfur

CO is a harmful gas to humans. It will suffocate you.

Explanation

CO is a harmful gas to humans. It will suffocate you.

11. The term _________________, when used in automotive circles, normally refers to the pollution produced by a light vehicle during operation of the vehicle or while sitting stationary.

Catalyst

Compression

Combustion

Emission

Emissions are the polluting discharge of a running vehicle.

Explanation

Emissions are the polluting discharge of a running vehicle.

12. ____________ is created when raw fuel evaporates into the atmosphere or when it does not burn at all in the combustion chamber and is exhausted out the tailpipe.

Carbon dioxide

Hydrocarbons

Carbon monoxide

Sulfur

Raw fuel is primary comprised of hydrogen and carbon.

Explanation

Raw fuel is primary comprised of hydrogen and carbon.

13. The evaporative emission (EVAP) system is designed to ensure that hydrocarbons are released into the atmosphere.

True

False

The EVAP emissions system's sole purpose is to harness evaporated HC and to direct it into the engine intake to be burned.

Explanation

The EVAP emissions system's sole purpose is to harness evaporated HC and to direct it into the engine intake to be burned.

14. In what year did it become mandatory for all vehicles to be on-board diagnostic II (OBDII) compliant?

1994

1995

1996

1997

Federally mandated OBD II was put into effect in 1996. It was a landmark year for the automotive industry.

Explanation

Federally mandated OBD II was put into effect in 1996. It was a landmark year for the automotive industry.

15. Tech A says that a closed-loop is when the feedback system is ignoring the sensors. Tech B says that a closed-loop is when the feedback system uses all the sensors to control the PCM. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Closed loop is when there is an intact feedback system and the PCM uses its inputs to make engine running adjustments.

Explanation

Closed loop is when there is an intact feedback system and the PCM uses its inputs to make engine running adjustments.

16. Tech A says that hydrocarbons are created when raw fuel does not burn completely in the combustion chamber and is exhausted out of the tailpipe. Tech B says that hydrocarbons are created when raw fuel evaporates into the atmosphere. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Raw fuel is primarily comprised of hydrogen and carbon, whether liquid or vapor.

Explanation

Raw fuel is primarily comprised of hydrogen and carbon, whether liquid or vapor.

17. ____________ is a by-product of complete combustion, along with water.

Carbon monoxide

Hydrocarbons

Carbon dioxide

Sulfur

CO2 is a by-product of complete combustion.

Explanation

CO2 is a by-product of complete combustion.

18. Tech A says that the positive crankcase ventilation (PCV) system removes blow-by gases from the crankcase in a manner that is not harmful to the environment. Tech B says that the PCV system prevents the build-up of crankcase pressure. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

The PCV system's responsibility is to recycle blow by gasses back into the engine to be burned. It also relives the build up of pressure created by these blow by gasses.

Explanation

The PCV system's responsibility is to recycle blow by gasses back into the engine to be burned. It also relives the build up of pressure created by these blow by gasses.

19. Tech A says that under high temperature and pressure of combustion, oxides of nitrogen are produced. Tech B says that oxides of nitrogen are only produced at temperatures less than 500°F. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

NOx is a by-product of incomplete combustion and will result in higher exhaust temperatures. NOx are created at all temperatures, but lots of them are created when there is extreme heat.

Explanation

NOx is a by-product of incomplete combustion and will result in higher exhaust temperatures. NOx are created at all temperatures, but lots of them are created when there is extreme heat.

20. Today's vehicle technology has reduced the harmful emissions on new vehicles to almost:

0%.

5%.

10%.

15%.

With all of the progressive technology available today, emissions of vehicles is approaching zero.

Explanation

With all of the progressive technology available today, emissions of vehicles is approaching zero.

21. Tech A says that the more oxygen the engine uses means the engine is running a rich mixture. Tech B says that the less oxygen the engine uses means the engine is running a lean mixture. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

More oxygen means an engine is running lean.

Explanation

More oxygen means an engine is running lean.

22. In what year did the catalytic convertor first make its appearance on automobiles' emission control systems?

1970

1971

1972

1973

1973 is the year when the catalytic converter premiered.

Explanation

1973 is the year when the catalytic converter premiered.

23. In what year was the positive crankcase ventilation (PCV) first used on vehicles' emission systems?

1959

1960

1961

1962

Another landmark year in automotive mechanics. 1961 is the year for the introduction of the PCV system.

Explanation

Another landmark year in automotive mechanics. 1961 is the year for the introduction of the PCV system.

24. Tech A says that the exhaust gas recirculation (EGR) valve does not function at idle. Tech B says that the EGR valve will not function during wide-open throttle (WOT). Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

The EGR valve mostly operates during cruising speeds. At idle, the engine will run very poorly. The need for performance supersedes the need for EGR system operation.

Explanation

The EGR valve mostly operates during cruising speeds. At idle, the engine will run very poorly. The need for performance supersedes the need for EGR system operation.

25. Tech A says that during open-loop operation, the engine control module (ECM) ignores the oxygen sensor signal and operates based on the last known ECM values. Tech B says that during ECM's last known values, the following sensors run: manifold absolute pressure (MAP) sensor, mass airflow (MAF) sensor, throttle position sensor (TPS), and intake air temperature (IAT) sensor. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

During the open loop, the ECM / PCM does ignore the O2 sensors, but it uses preprogrammed values to run the engine. The MAP is an active value. To run well, it needs current readings.

Explanation

During the open loop, the ECM / PCM does ignore the O2 sensors, but it uses preprogrammed values to run the engine. The MAP is an active value. To run well, it needs current readings.