ENGINE REPAIR Flashcards

1
Q

A vehicle fails to start but cranks normally. Tech A says that a fuel system issue could be the cause. Tech B says that a problem with the ignition system might be responsible. Who is Right?

A

Both are right

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2
Q

A vehicle exhibits excessive blue smoke from the exhaust. Tech A says that this indicates a rich fuel mixture. Tech B says that it indicates oil burning. Who is right?

A

Tech B is correct

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3
Q

When performing a cylinder compression test, all of the following steps are correct EXCEPT:

A: Disabling the ignition system
B: Removing all spark plugs
C: Cranking the engine for several revolutions
D: Measuring compression with the engine hot

A

D is the correct answer.

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4
Q

A vehicle is brought in with an engine misfire. Tech A says that the issue could be due to a cracked cylinder head. Tech B says that the problem may be caused by a worn camshaft lobe. Who is right?

A

Both are correct

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5
Q

A technician is inspecting valve springs. Tech A says to check for squareness using a machinists square. Tech B says to check spring pressure using a valve spring tester. Who is right?

A

Both are correct

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6
Q

When inspecting valve guides for wear, Tech A says to measure the valve stem-to-guide clearance with a dial indicator. Tech B says to use a small-hole gauge and micrometer. Who is right?

A

Both are correct

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7
Q

All of the following statements about camshaft inspection are true EXCEPT:

A: measure camshaft lift using a dial indicator
B: Inspect camshaft loves for wear and pitting
C: Use a plasitgauge to measure camshaft journal clearance
D: Check camshaft timing using a timing light

A

Correct answer is D

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8
Q

A vehicle has a rough idle. Tech A says to inspect the valve seats for damage. Tech B says to check the valve timing. Who is right?

A

Both are correct

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9
Q

A cylinder head is being inspected for cracks. Tech A says to use a magnetic particle tester. Tech B says to use a vacuum tester. Who is right?

A

Tech A is correct

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10
Q

A vehicle exhibits low compression in one cylinder. Tech A says to inspect the valve for burning. Tech B says to inspect the piston for damage. Who is correct?

A

Both are correct

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11
Q

All of the following steps are part of adjusting the valves on an engine with hydraulic lifters EXCEPT:

A: Rotate the engine to TDC on the compression stroke
B: Adjust the valves with the engine running
C: Use a feeler gauge to set the valve lash
D: Follow the manufacturer’s sequence for adjustment

A

Correct answer is C

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12
Q

During a visual inspection, all of the following should be checked EXCEPT:

A: Cracks in the engine block
B: Surface warpage
C: Condition of piston rings
D: Corrosion in passages

A

Correct answer is C

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13
Q

When inspecting auxiliary shafts for damage and wear, which of the following should be checked?

A: Piston rings
B: Drive chains
C: Cylinder walls
D: Fuel Injectors

A

Correct answer is B

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14
Q

The least likely result of improper installation of piston rings would be?

A: Increased oil consumption
B: Poor compression
C: Engine knocking
D: Reduced fuel efficiency

A

Correct answer is D

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15
Q

During crankshaft vibration damper/harmonic balancer inspection, which of the following is NOT typically inspected?

A: Proper installation
B: Physical damage
C: Surface finish
D: Flexplate condition

A

Correct answer is D

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16
Q

An engine is exhibiting low oil pressure. Tech A says that the oil pressure test should be performed to diagnose the issue. Tech B says that an oil dye test should be performed to check for valve leaks. Who is right?

A

Both are correct

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17
Q

A vehicle exhibits reduced power and excessive exhaust smoke. Tech A says the turbocharger may be failing. Tech B says the air filter might be clogged. Who is right?

A

Both are correct

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18
Q

A vehicles engine shows signs of oil leaks around the PCV valve. Tech A says the PCV valve might be clogged. Tech B says the valve cover gasket may be leaking. Who is correct?

A

Both are correct

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19
Q

A vehicle is brought in with a high-pitched whine from the engine bay. Tech A says it could be a failing supercharger. Tech B says it might be the alternator. Who is right?

A

Both are correct

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20
Q

All of the following are reasons to replace a fuel injector EXCEPT:

A: It is clogged
B: It is leaking fuel
C: it is emitting a loud noise
D: It is providing an inconsistent spray pattern

A

Correct answer is C

21
Q

A vehicle with poor acceleration is being diagnosed Tech A says the mass air flow sensor could be dirty. Tech B says the turbocharger wastegate might be stuck open. Who is correct?

A

Both are correct

22
Q

According to Tech A, insufficient hydraulic lifter preload causes excessive valve train noise. According to Tech B, excessive hydraulic lifter preload causes a high intake manifold vacuum. Who is correct?

A

Tech A. The lifter will not maintain proper contact with the pushrod and rocker arm. This can lead to a tapping or ticking noise that is most noticeable at idle.

23
Q

You find a flapping sound near an engines front, why do you hear this sound?

Timing belt tension
Loose drive belt
Tight drive belt
Too loose timing belt tension

A

Correct answer is D.

24
Q

Which of the following leads to a drop in oil pressure?

A: A stuck closed oil pressure relief valve
B: A clogged oil pressure relief valve
C: Worn crankshaft bearings
D: A restriction in the oil filter

A

Correct answer is C

Overtime the bearings can wear out, which allows more oil to escape from the bearing surfaces

25
Q

The aluminum thermostat housing of an engine has deteriorated prematurely and is leaking coolant. Which of the following is the MOST LIKELY reason?

A: A faulty thermostat
B: Electrolysis
C: Engine overheating
D: A leaking radiator hose

A

Correct answer is B.

Electrolysis occurs when there is an electrical current passing through the coolant that comes into contact with the aluminum

26
Q

A rough idle engine is subjected to a vacuum test. At idle, the needle on the gauge varies between 15 ‘‘hg and 20 ‘‘hg vacuum. This reading indicates what?

A: Late ignition or valve timing
B: A sticking valve or engine misfire
C: A restricted exhaust system
D: A normal condition

A

Correct answer is B

A steady normal reading is 17-22 hg

27
Q

A customer complains that his engine has a rattling noise. The tech detects that the noise originates from the drive belt/serpentine belt system. What should you do next?

A: Inspect drive belt for wear
B: Replace drive belt tensioner
C: Inspect pulleys for wear and damage
D: Replace the drive belt

A

Correct answer is C

28
Q

A cylinder compression test reveals that the #1 cylinder falls short of specs. The pressure remains the same after the injection of oil. Which of the following could be the root of the problem?

A: A faulty head gasket
B: Worn piston rings
C: A bad valve
D: A hole in the piston

A

Correct answer is C

A bad valve can cause a loss of compression, as could a faulty head gasket

29
Q

A cylinder power balance test on a sequentially injected engine reveals that the #5 cylinder is underperforming. According to Tech A, this could be the result of a clogged fuel injector. According to Tech B, this could be due to leaking secondary insulation. Who is correct?

A

Both are correct

Clogged fuel injector is a common cause of cylinder misfires

If the secondary insulation is leaking, it allows electricity to be conducted away from the spark plug instead of firing it

30
Q

Camshaft duration, according to Tech A, is the distance the camshaft lobe lifts the valve off the valve seat and into the cylinder. According to Tech B, valve overlap happens when both intake and exhaust valves are open at the same time. Who is correct?

A

Tech B.

Camshaft duration, lift, and overlap are vital to valve timing and engine performance. Camshaft duration refers to time it affects the valves opening and closing and how long it stays open.

31
Q

Which of the following is the MOST probable cause of an engines turbocharger producing excessive boost?

A: None of these answers
B: A stuck closed wastegate
C: An intake manifold
D: A stuck open wastegate

A

Correct answer is B

A stuck closed wastegate is the most likely source of too much boost in an engine with a turbo charger. The wastegate is a valve that controls the amount of exhaust gas that enters the turbocharger which then controls the amount of boost

32
Q

All of these tools are used to repair a small crack in the cast-iron engine block using the metal pinning method, EXCEPT:

A: A grinder
B: A drill bit
C: A welding rod
D: A tap

A

Correct answer is C

The metal pinning method involves drilling holes on either side of the crack in the engine block, grinding the surface around the crack to create a clean and smooth area and then tapping the holes with a tap

33
Q

A faulty main bearing __________.

A: Usually leads to a heavy knocking noise and low engine pressure, especially while idling

B: Makes a thumping noise thats noticeable when the engine first starts

C: Could cause thumping during idle

D: Doesn’t cause a noise unless its severely worn

A

Correct answer is B

34
Q

The first thing to do when attempting to diagnose coolant consumption is _________.

A: Check engine oil condition and level

B: Check the coolant level and condition

C: Perform a cooling system pressure test

D: Determine the extent of the damage

A

Correct answer is C

35
Q

An engine with too much crankshaft endplay. Which of the following is the MOST LIKELY to be the source of the condition?

A: Crankshaft main bearings
B: Camshaft bearings
C: Thrust bearings
D: Rod bearings

A

Correct answer is C

Thrust bearings are located on the ends of the crankshaft and are designed to control the axial movement of the crankshaft as it rotates

36
Q

A customer comes in complaining about their sudden engine power lack. After inspecting, the tech finds out that the engine coolant is low. Additionally, there is white smoke coming from the exhaust. Which is the BEST explanation.

A: A blown head gasket
B: Worn piston ring
C: Cracked cylinder wall
D: Faulty valve guide

A

Correct answer is C

Cracked cylinder wall can lead to loss of compression which results in power lack

37
Q

The knocking sound of a high milage engine fades as it warms and achieves operating temp. What is the MOST LIKELY reason?

A: The viscosity of the engine oil increases
B: Loose crankshaft main bolts
C: Loose flywheel bolts
D: A loose timing belt
E: Piston to wall clearance

A

Correct answer is E

As the engine warms up the metal expands which reduces the clearance between the pistons and cylinder walls

38
Q

After being removed from a cylinder head, the valve springs should be checked for _________.

A: Both options
B: Neither
C: Valve spring installed height with a ruler
D: Squareness with a square and a feeler gauge

A

Correct answer is D

39
Q

Based on the cylinder power balance test result, what is the MOST LIKELY reason for two adjacent cylinders to be underperforming?

A: A faulty fuel injector
B: A leaking head gasket
C: A bad exhaust valve
D: Worn piston rings

A

Correct answer is B

40
Q

An engine begins making a knocking sound that changes with the RPM, however the noise disappears during a balance test. What is the MOST feasible reason?

A: Piston slap
B: Main bearing
C: Burnt valve
D: Connecting rod bearings

A

Correct answer is D

41
Q

Which of the following statements is NOT CORRECT when adjusting valve lash on engines with overhead camshaft cylinder heads?

A: Shims may be used to make adjustments
B: Clearance is measured between the camshaft and follow or rocker on most engines
C: The follower or rocker must be on the base circle of the camshaft when measuring
D: The engine must be cold for all engine manufacturers

A

The correct answer is D

Metal components expand

42
Q

What could be the reason for a coolant leak from an engine and a radiator pressure tester mounted on the radiator’s neck showing a rise in pressure to 19 psi soon after starting the engine, while the engine is cold?

A: Theres an air pocket in the engine
B: Acidic engine coolant
C: The pressure is normal
D: The cylinder head gasket is leaking

A

Correct answer is D

The head gasket is meant to hold compression

43
Q

The cylinder head’s surface has just been machined. What change could be made to make the valve train better?

A: All of the answers
B: Shim the head
C: Increasing valve spring tension
D: lengthening the push rods
E: Grinding the valve stems

A

The correct answer is E

Grinding the valve stems is a common procedure that is done to compensate for the reduced distance between the rocker and the pushrod

44
Q

A turbocharger wastegate has become stuck. According to Tech A an open wastegate will cause overboost. According to Tech B, a stuck closed waste gate will cause in underboost. Who is correct?

A

Neither are correct

45
Q

If the teeth on the flywheels ring gear are worn, tech a suggest the ring gear can be removed and replaced. Tech b says minor scoring on the surface of a flywheel can be removed by resurfacing. Who is correct?

A

Both are correct

46
Q

Which of the following option is the BEST way to determine a defective injector without its manufacture electrical specifications?

A: determine if all injectors have the same electrical resistance
B: Look to see if they squirt fuel
C:Remove them and clean them
D: Test for fuel pressure at the fuel rail

A

Correct answer is A

47
Q

Performing a wet compression test on a four-cylinder enngine reveals that the compression in the number two cylinder is below the specified levels. However, even after adding oil during the test, the compression does not show any improvement. This result suggests that the issue lies in _________.

A: A hole in the piston
B: Worn piston rings
C: Excessive carbon build up on the pistons dome
D: A faulty valve

A

Correct answer is D

48
Q

The electrode of a spark plug is covered in thick black carbon deposits. Which of the following could be the reason?

A: The fuel injector is leaking
B: This reading shows normal wear
C: The engine has a vacuum leak
D: The piston rings are worn

A

The correct answer is D

49
Q
A