Comprehensive Engine Performance Assessement
Most cars have engines that distinguish them from all the others. There are certain components of an engine that are uniform where as others are totally different. Below is a comprehensive engine performance assessment quiz that is designed to see just how much you know when it comes to engines. Give it a try and see if you should pick up a book to refresh your mind.
- 1.
True or False. The evaporative emission (EVAP) system is designed to ensure that hydrocarbons are released into the atmosphere.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The EVAP emissions system's sole purpose is to harness evaporated HC and to direct it into the engine intake to be burned.Rate this question:
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- 2.
True or False. The main concern of the evaporative emission (EVAP) system is the gas cap.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Yes, the fuel filler cap is by far the most over looked component of the EVAP emissions system, by both customers and technicians.Rate this question:
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- 3.
True or False. The illuminated malfunction indicator lamp (MIL) lets the tech know that there is an emission problem that needs to be diagnosed.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The check engine light or malfunction indicator lamp are responsible of notifying the driver of a concern with emission regulation equipment.Rate this question:
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- 4.
Emissions can be caused naturally by:
- A.
Forest fires.
- B.
Volcanoes.
- C.
Decomposition of materials.
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Emissions are a product of combustion. Combustion is naturally occurring and so are instances that aren't man made.Rate this question:
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- 5.
In automotive applications, most_______________ is/are a by-product of combustion and is/are emitted from the exhaust system.
- A.
Fuel
- B.
Air
- C.
Emissions
- D.
Catalysts
Correct Answer
C. EmissionsExplanation
Most emissions created from cars is from the tailpipe.Rate this question:
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- 6.
Today's vehicle technology has reduced the harmful emissions on new vehicles to almost:
- A.
0%.
- B.
5%.
- C.
10%.
- D.
15%.
Correct Answer
A. 0%.Explanation
With all of the progressive technology available today, emissions of vehicles is approaching zero.Rate this question:
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- 7.
The term _________________, when used in automotive circles, normally refers the pollution produced by a light vehicle during operation of the vehicle or while sitting stationary.
- A.
Catalyst
- B.
Compression
- C.
Combustion
- D.
Emission
Correct Answer
D. EmissionExplanation
Emissions are the polluting discharge of a running vehicle.Rate this question:
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- 8.
Today's emissions come from the vehicle's:
- A.
Fuel system.
- B.
Crankcase.
- C.
Tailpipe.
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Unwanted vehicle emissions are created from all of the above.Rate this question:
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- 9.
In what year did it become mandatory for all vehicles to be on-board diagnostic II (OBDII) compliant?
- A.
1994
- B.
1995
- C.
1996
- D.
1997
Correct Answer
C. 1996Explanation
Federally mandated OBD II was put into effect in 1996. It was a landmark year for the automotive industry.Rate this question:
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- 10.
What does the Environmental Protection Agency (EPA) require all vehicles to have to warn the driver of an emission fault?
- A.
A beeping horn
- B.
An illuminated light
- C.
A buzzing buzzer
- D.
A ringing bell
Correct Answer
B. An illuminated lightExplanation
A light MUST BE in every vehicle that has OBD II.Rate this question:
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- 11.
A limit value is the maximum amount of _____________ that a vehicle is permitted to emit.
- A.
Speed
- B.
Emissions
- C.
Air
- D.
Water
Correct Answer
B. EmissionsExplanation
There is a limit on how much of each harmful gas a vehicle can emit.Rate this question:
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- 12.
____________ is a by-product of complete combustion, along with water.
- A.
Carbon monoxide
- B.
Hydrocarbons
- C.
Carbon dioxide
- D.
Sulfur
Correct Answer
C. Carbon dioxideExplanation
CO2 is a by-product of complete combustion.Rate this question:
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- 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 tail pipe.
- A.
Carbon dioxide
- B.
Hydrocarbons
- C.
Carbon monoxide
- D.
Sulfur
Correct Answer
B. HydrocarbonsExplanation
Raw fuel is primary comprised of hydrogen and carbon.Rate this question:
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- 14.
______________ is a colorless, odorless, tasteless, flammable, and highly toxic gas.
- A.
Carbon dioxide
- B.
Hydrocarbons
- C.
Carbon monoxide
- D.
Sulfur
Correct Answer
C. Carbon monoxideExplanation
CO is a harmful gas to humans. It will suffocate you.Rate this question:
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- 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:
- A.
34.3:1.
- B.
17.2:1.
- C.
15.7:1.
- D.
14.7:1.
Correct Answer
D. 14.7:1.Explanation
14.7:1 is the sweet spot for engine performance and emissions.Rate this question:
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- 16.
Tech A says that closed loop is when the feedback system is ignoring the sensors. Tech B says that closed loop is when the feedback system uses all the sensors to control the PCM. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
B. Tech BExplanation
Closed loop is when there is an intact feedback system and the PCM uses its inputs to make engine running adjustments.Rate this question:
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- 17.
Tech A says that hydrocarbons are created when raw fuel does not burn completely in the combustion chamber and is exhausted out the tailpipe. Tech B says that hydrocarbons are created when raw fuel evaporates into the atmosphere. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
Raw fuel is primarily comprised of hydrogen and carbon, whether liquid or vapor.Rate this question:
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- 18.
Tech A says that carbon monoxide is lethal. Tech B says never run an engine inside a closed shop without proper exhaust ventilation. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
CO will kill you. An engine running in an unventelated shop will harbor this deadly gas.Rate this question:
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- 19.
Tech A says that under high temperature and pressure of combustion, oxides of nitrogen is produced. Tech B says that oxides of nitrogen are only produced at temperatures less than 500°F. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
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.Rate this question:
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- 20.
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 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?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
D. Neither Tech A nor BExplanation
During 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.Rate this question:
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- 21.
In what year was the positive crankcase ventilation (PCV) first used on vehicles' emission systems?
- A.
1959
- B.
1960
- C.
1961
- D.
1962
Correct Answer
C. 1961Explanation
Another landmark year in automotive mechanics. 1961 is the year for the introduction of the PCV system.Rate this question:
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- 22.
In what year did the catalytic convertor first make its appearance on automobiles' emission control systems?
- A.
1970
- B.
1971
- C.
1972
- D.
1973
Correct Answer
D. 1973Explanation
1973 is the year when the catalytic converter premiered.Rate this question:
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- 23.
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?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
B. Tech BExplanation
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.Rate this question:
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- 24.
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?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
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.Rate this question:
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- 25.
Which of the following methods may be used to manually perform a cylinder power balance test?
- A.
Unplug the ignition from each cylinder.
- B.
Unplug the fuel injectors.
- C.
Both A and B
- D.
None of the above
Correct Answer
C. Both A and BExplanation
To perform a power balance test, either the ignition or the fuel can be disabled.Rate this question:
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- 26.
When testing intake manifold vacuum, the gauge needle oscillates back and forth rapidly, which generally indicates:
- A.
A partially restricted exhaust
- B.
A mechanical condition such as a burned or bent valve.
- C.
Late ignition or valve timing.
- D.
None of the above
Correct Answer
B. A mechanical condition such as a burned or bent valve.Explanation
The needle oscillations are an indication of an internal mechanical fault, which occurs as rapidly as the engine turns.Rate this question:
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- 27.
When checking cranking compression, which of the following malfunctions is either confirmed or ruled out by performing a wet test on a cylinder with low compression?
- A.
None of the above
- B.
A small hole in the top of the piston
- C.
A burned exhaust valve
- D.
A leaking cylinder head gasket
Correct Answer
A. None of the aboveExplanation
A wet compression test validates the seal provided by the piston rings.Rate this question:
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- 28.
When performing a cylinder leakage test, a small amount of air leakage can be heard from the exhaust tail pipe. This indicates:
- A.
Worn valve guides.
- B.
A bent intake valve.
- C.
A leaking cylinder head gasket.
- D.
A bad exhaust valve
Correct Answer
D. A bad exhaust valveExplanation
A leak heard from the associated part of the compression chamber will lead you to the bad sealing component.Rate this question:
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- 29.
Tech A says that a slightly lean mixture offers good fuel economy and low exhaust emissions. Tech B says that a mixture that is too rich fouls spark plugs and causes incomplete burning. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
Both Tech A and Tech B are correct. A slightly lean mixture, meaning there is more air than fuel, can offer good fuel economy and low exhaust emissions. On the other hand, a mixture that is too rich, meaning there is more fuel than air, can foul spark plugs and cause incomplete burning. Therefore, both statements are accurate and provide valid explanations for the effects of different fuel mixtures.Rate this question:
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- 30.
The purpose of the vehicle speed sensor (VSS) is to measure the:
- A.
Turbulence in the incoming airstream.
- B.
Throttle position.
- C.
Speed of the vehicle.
- D.
Coolant temperature.
Correct Answer
C. Speed of the vehicle.Explanation
VSS is an acronym for vehicle speed sensor.Rate this question:
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- 31.
Tech A says that engine misfiring will cause a lean exhaust condition. Tech B says that engine misfiring can cause overheating of the catalytic converter. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
B. Tech BExplanation
When an cylinder misfires, the fuel remains unburned. The catalyst speeds the reaction of converting unwanted combustion by-products into safer emissions. This process is exothermic and is exaggerated when there is an excess of hydrocarbons in the exhaust.Rate this question:
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- 32.
The on and off time of a stepper motor relates to its duty cycle, which is generally expressed as a:
- A.
Percentage.
- B.
Numeric value.
- C.
Binary number.
- D.
Hexi-decimal value.
Correct Answer
A. Percentage.Explanation
The amount of time something is on or off, the duty cycle, is expressed as a percentage.Rate this question:
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- 33.
A variation in pulse width at a fixed frequency is called:
- A.
Duty cycle.
- B.
Analog cycle.
- C.
Pulse-width modulation.
- D.
Digital cycle.
Correct Answer
C. Pulse-width modulation.Explanation
The control for the duty cycle is called a pulse width modulation.Rate this question:
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- 34.
Tech A says that fuel pump pressure can often be tested by accessing a test port. Tech B says that fuel pump volume can be affected by the condition of the fuel injectors. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
If there is a test port to test supply pressure, that's the way to go.
The fuel pump determines the amount of fuel delivered. The injectors only open and close.Rate this question:
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- 35.
A high-voltage spark must cross the spark plug electrode as the piston approaches top dead center (TDC) of the
- A.
Exhaust stroke.
- B.
Ignition stroke.
- C.
Intake stroke.
- D.
Compression stroke.
Correct Answer
D. Compression stroke.Explanation
Once the fuel and air mixture has compressed, a spark is needed to ignite the mixture.Rate this question:
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- 36.
The type of ignition system in which two cylinders share one coils is called a:
- A.
Distributor ignition system.
- B.
Waste spark ignition system.
- C.
Coil-on plug ignition system.
- D.
None of the above
Correct Answer
B. Waste spark ignition system.Explanation
It's called waste spark because it fires on a pair of engine cylinders on opposite engine cycles.Rate this question:
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- 37.
The collapse of the magnetic field inside the ignition coil happens as a result of the interruption of current to the:
- A.
Primary winding.
- B.
Secondary winding.
- C.
Ignition control module.
- D.
Electronic control module (ECM).
Correct Answer
A. Primary winding.Explanation
The collapse of voltage occurs on the primary side of the ignition coil.Rate this question:
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- 38.
The pattern in which a lab scope shows all the cylinders firing in sequence is called the:
- A.
Parade pattern.
- B.
Raster pattern.
- C.
Spark line.
- D.
Firing line.
Correct Answer
A. Parade pattern.Explanation
On an lab scope, the spark voltages as they are read is called a parade pattern.Rate this question:
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- 39.
Tech A says that ignition coils are essentially transformers. Tech B says that the primary side of the coil delivers the high voltage spark that is necessary to jump the plug gap. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
Ignition coils transform low voltage into high voltage to jump the gap of the spark plug. The secondary side delivers the high voltage to jump this gap.Rate this question:
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- 40.
Tech A says that the crankshaft sensor is used to determine vehicle speed. Tech B says the cam sensor is used to control fuel pump speed. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
D. Neither Tech A nor BExplanation
The vehicle speed sensor (VSS) is responsible for inputting vehicle speed.
The cam sensor is responsible for inputting camshaft position to the ECM.Rate this question:
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- 41.
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?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
D. Neither Tech A nor BExplanation
Tech A's statement is incorrect because a rich mixture means there is more fuel relative to the amount of oxygen, not necessarily more oxygen usage. Tech B's statement is also incorrect because a lean mixture means there is more oxygen relative to the fuel, but it does not imply that less oxygen is being used overall. In fact, a lean mixture has more oxygen available compared to fuel, contrary to Tech B's statement.Rate this question:
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Sep 02, 2024Quiz Edited by
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Dec 08, 2014Quiz Created by
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