1.
The evaporative emission (EVAP) system is designed to ensure that hydrocarbons are released into the atmosphere.
Correct Answer
B. False
Explanation
The EVAP emissions system's sole purpose is to harness evaporated HC and to direct it into the engine intake to be burned.
2.
The main concern of the evaporative emission (EVAP) system is the gas cap.
Correct Answer
A. True
Explanation
Yes, the fuel filler cap is by far the most overlooked component of the EVAP emissions system, by both customers and technicians.
3.
The illuminated malfunction indicator lamp (MIL) lets the tech know that there is an emission problem that needs to be diagnosed.
Correct Answer
A. True
Explanation
The check engine light or malfunction indicator lamp is responsible for notifying the driver of a concern with emission regulation equipment.
4.
Emissions can be caused naturally by:
Correct Answer
D. All of the above
Explanation
Emissions are a product of combustion. Combustion is naturally occurring and so are instances that aren't man-made.
5.
In automotive applications, most_______________ is/are a by-product of combustion and is/are emitted from the exhaust system.
Correct Answer
C. Emissions
Explanation
Most emissions created from cars is from the tailpipe.
6.
Today's vehicle technology has reduced the harmful emissions on new vehicles to almost:
Correct Answer
A. 0%.
Explanation
With all of the progressive technology available today, emissions of vehicles is approaching zero.
7.
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.
Correct Answer
D. Emission
Explanation
Emissions are the polluting discharge of a running vehicle.
8.
Today's emissions come from the vehicle's:
Correct Answer
D. All of the above
Explanation
Unwanted vehicle emissions are created from all of the above.
9.
In what year did it become mandatory for all vehicles to be on-board diagnostic II (OBDII) compliant?
Correct Answer
C. 1996
Explanation
Federally mandated OBD II was put into effect in 1996. It was a landmark year for the automotive industry.
10.
What does the Environmental Protection Agency (EPA) require all vehicles to have to warn the driver of an emission fault?
Correct Answer
B. An illuminated light
Explanation
A light MUST BE in every vehicle that has OBD II.
11.
A limit value is the maximum amount of _____________ that a vehicle is permitted to emit.
Correct Answer
B. Emissions
Explanation
There is a limit on how much of each harmful gas a vehicle can emit.
12.
____________ is a by-product of complete combustion, along with water.
Correct Answer
C. Carbon dioxide
Explanation
CO2 is a by-product of complete combustion.
13.
____________ 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.
Correct Answer
B. Hydrocarbons
Explanation
Raw fuel is primary comprised of hydrogen and carbon.
14.
______________ is a colorless, odorless, tasteless, flammable, and highly toxic gas.
Correct Answer
C. Carbon monoxide
Explanation
CO is a harmful gas to humans. It will suffocate you.
15.
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:
Correct Answer
D. 14.7:1.
Explanation
14.7:1 is the sweet spot for engine performance and emissions.
16.
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?
Correct Answer
B. Tech B
Explanation
Closed loop is when there is an intact feedback system and the PCM uses its inputs to make engine running adjustments.
17.
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?
Correct Answer
D. Neither Tech A nor B
Explanation
More oxygen means an engine is running lean.
18.
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?
Correct Answer
C. Both Techs A and B
Explanation
Raw fuel is primarily comprised of hydrogen and carbon, whether liquid or vapor.
19.
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?
Correct Answer
C. Both Techs A and B
Explanation
CO will kill you. An engine running in an unventelated shop will harbor this deadly gas.
20.
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?
Correct Answer
A. Tech A
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.
21.
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?
Correct Answer
D. Neither Tech A nor B
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.
22.
In what year was the positive crankcase ventilation (PCV) first used on vehicles' emission systems?
Correct Answer
C. 1961
Explanation
Another landmark year in automotive mechanics. 1961 is the year for the introduction of the PCV system.
23.
In what year did the catalytic convertor first make its appearance on automobiles' emission control systems?
Correct Answer
D. 1973
Explanation
1973 is the year when the catalytic converter premiered.
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?
Correct Answer
B. Tech B
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 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?
Correct Answer
C. Both Techs A and B
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.