Trivia Quiz On Engine Mechanical System!
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Questions and Answers
- 1.
The process of mechanical testing will first help you identify the location of a mechanical problem and then identify the cause of the fault.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because mechanical testing is a systematic process that involves evaluating the performance and functionality of mechanical systems or components. By conducting mechanical testing, it becomes possible to identify any potential issues or faults in the system. This can be done by analyzing the performance data, conducting visual inspections, or using specialized tools and equipment. Once the location of the problem is identified, further testing and analysis can be done to determine the cause of the fault. Overall, mechanical testing plays a crucial role in diagnosing and resolving mechanical problems.Rate this question:
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- 2.
What unit of measure is used when testing engine compression and cylinder leakage?
- A.
Pounds per square inch (psi)
- B.
Kilopascals (kPa)
- C.
Both A and B
- D.
Pound feet
Correct Answer
C. Both A and BExplanation
Both pounds per square inch (psi) and kilopascals (kPa) are units of measure that can be used when testing engine compression and cylinder leakage. These units measure the pressure exerted on the engine and can indicate any leaks or issues with the compression in the cylinders. Using both units allows for flexibility and compatibility with different testing equipment and standards.Rate this question:
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- 3.
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 B.Explanation
To perform a power balance test, either the ignition or the fuel can be disabled.Rate this question:
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- 4.
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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- 5.
How even should the cranking compression be between the lowest and highest cylinder readings on an engine without mechanical problems?
- A.
Within 5%
- B.
Within 3%
- C.
Within 14%
- D.
Within 10%
Correct Answer
D. Within 10%Explanation
The cranking compression between the lowest and highest cylinder readings on an engine without mechanical problems should be within 10%. This means that there can be a maximum difference of 10% in compression levels between the lowest and highest cylinder readings. If the difference exceeds 10%, it may indicate potential mechanical issues within the engine.Rate this question:
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- 6.
Which of the following malfunctions would be revealed during a running compression test?
- A.
A burned exhaust valve
- B.
A badly worn camshaft lobe
- C.
Both A and B
- D.
None of the above
Correct Answer
C. Both A and BExplanation
During a running compression test, the engine is running and the compression is measured in each cylinder. A burned exhaust valve would be revealed because it would result in a loss of compression in the affected cylinder. Similarly, a badly worn camshaft lobe would also cause a loss of compression, as it would prevent the valve from opening and closing properly. Therefore, both A and B would be revealed during a running compression test.Rate this question:
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- 7.
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.
A small hole in the top of the piston
- B.
A burned exhaust valve
- C.
A leaking cylinder head gasket
- D.
None of the above
Correct Answer
D. None of the aboveExplanation
A wet compression test validates the seal provided by the piston rings.Rate this question:
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- 8.
When performing a cylinder leakage test, a small amount of air leakage can be heard from the exhaust tailpipe. This indicates:
- A.
Worn valve guides.
- B.
A bad exhaust valve
- C.
A bent intake valve.
- D.
A leaking cylinder head gasket.
Correct Answer
B. 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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- 9.
When testing cranking compression, Tech A says that all engines may be disabled to avoid starting by placing a shop rag in the engine intake. Tech B says that an engine may be disabled by removing the fuel pump relay (if equipped). 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
All engines should be disabled by removing fuel delivery from the engine.Rate this question:
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- 10.
Which of the following can be measured by a running compression test, but NOT by a cranking compression test?
- A.
The sealing capability of the valves.
- B.
The sealing capability of the rings and pistons.
- C.
Bad piston rings.
- D.
None of the above.
Correct Answer
D. None of the above.Explanation
A running compression test measures the compression pressure in the cylinders while the engine is running. This test can help identify any issues with the sealing capability of the valves, rings, and pistons. It can also detect problems such as bad piston rings. Therefore, all of the options mentioned in the question can be measured by a running compression test, making the correct answer "None of the above."Rate this question:
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- 11.
When performing a cranking compression test, Tech A says the final reading should be reached on the second compression pulse. Tech B says the first compression pulse should read at least half as much as the final reading. 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
Tech B is correct. In a cranking compression test, the first compression pulse should read at least half as much as the final reading. This is because the first pulse indicates the initial compression of the engine, while the final reading represents the maximum compression achieved. Therefore, Tech B's statement is accurate.Rate this question:
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- 12.
Techs A and B are discussing how to obtain the most accurate results when testing cranking compression on a gasoline engine. Tech A says the battery must be at least half charged. Tech B says at least three compression pulses should be made on each cylinder while watching the gauge. 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 batter needs to be at full capacity to get sufficient engine speed, and you should attempt to get 5 pulses in each cylinder when performing the test.Rate this question:
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- 13.
When leak-down testing a cylinder with high leakage, air escaping from the spark plug hole of an adjacent cylinder would indicate a possible?
- A.
Hole in the piston
- B.
Intake valve
- C.
Exhaust valve
- D.
Head gasket
Correct Answer
D. Head gasketExplanation
The head gasket is shared between cylinders and, without any other indicators, is the most likely cause of leakage.Rate this question:
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- 14.
In order to leak check a cylinder, the piston must be on the intake stroke.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
This is false. When conducting a leak down test, the cylinder needs to have a piston at TDC of the compression stroke.Rate this question:
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- 15.
When diagnosing an engine misfire, what test is used to determine the misfiring cylinder?
- A.
Engine vacuum test
- B.
Power balance test
- C.
Cranking compression test
- D.
Cylinder leak-down test
Correct Answer
B. Power balance testExplanation
A power balance test will lead you to the cylinder that is misfiring.Rate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Oct 08, 2014Quiz Created by
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