Technician Practice Exam Questions

ASE A1 Engine Repair (Automobile Technician) Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of engine oil?

a) To cool the radiator

b) To lubricate moving parts

c) To increase fuel efficiency

d) To clean fuel injectors

Rationale: Engine oil reduces friction and wear between moving

parts, preventing damage and overheating.

• What component converts the linear motion of the piston into rotary

motion?

a) Crankshaft pulley

b) Camshaft 1 / 4

c) Crankshaft

d) Timing chain

Rationale: The crankshaft translates the pistons’ up-and-down

motion into rotational motion to drive the drivetrain.

• Which type of engine uses spark plugs for ignition?

a) Diesel engine

b) Gasoline engine

c) Rotary engine

d) Turbodiesel engine

Rationale: Gasoline engines rely on spark plugs to ignite the air-fuel

mixture, unlike diesel engines which use compression ignition.

• What is the most common cause of engine knocking?

a) Low oil level

b) Low-octane fuel

c) Faulty water pump

d) Clogged fuel filter

Rationale: Using fuel with insufficient octane can cause premature

combustion, resulting in knocking.

• Which sensor monitors the temperature of the engine coolant?

a) MAP sensor

b) Engine Coolant Temperature (ECT) sensor

c) Oxygen sensor

d) Crankshaft position sensor 2 / 4

Rationale: The ECT sensor measures coolant temperature and sends

data to the ECU to regulate fuel and ignition timing.

• What is the purpose of the piston rings?

a) To keep the piston centered in the cylinder

b) To reduce noise

c) To seal the combustion chamber and control oil consumption

d) To connect the piston to the crankshaft

Rationale: Piston rings prevent combustion gases from leaking and

control oil flow between the piston and cylinder wall.

• Which engine component controls the timing of the intake and

exhaust valves?

a) Crankshaft

b) Timing belt tensioner

c) Camshaft

d) Oil pump

Rationale: The camshaft rotates in sync with the crankshaft to open

and close valves at precise intervals.

• What does a compression test measure?

a) Oil pressure

b) Coolant flow

c) Cylinder pressure during piston compression

d) Fuel pressure 3 / 4

Rationale: A compression test determines the ability of cylinders to

compress the air-fuel mixture, indicating engine health.

• What is a primary symptom of a blown head gasket?

a) Low oil pressure

b) White smoke from the exhaust

c) Engine knocking

d) Hard starting

Rationale: A blown head gasket can allow coolant into the

combustion chamber, producing white exhaust smoke.

• What is the main function of the timing belt?

a) Drive the alternator

b) Operate the fuel pump

c) Synchronize the crankshaft and camshaft

d) Regulate oil flow

Rationale: The timing belt ensures that valves open and close at the

correct time relative to piston movement.

• What is the purpose of valve lash adjustment?

a) Improve fuel economy

b) Increase oil pressure

c) Ensure proper valve clearance

d) Prevent piston seizure

Rationale: Correct valve clearance ensures proper engine

performance and prevents valve and camshaft damage.

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