ASE AUTOMOBILE TECHNICIAN A1
ENGINE REPAIR PRACTICE EXAM
QUESTION AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A INSTANT DOWNLOAD PDF
1. A compression test shows one cylinder significantly lower than the others.
What is the MOST likely cause?
A. Faulty spark plug
B. Worn piston rings
C. Incorrect ignition timing
D. Restricted exhaust
B. Worn piston rings
Rationale: Low compression in a single cylinder commonly indicates worn
or damaged piston rings allowing pressure to leak past the piston.
2. Blue smoke from the exhaust during acceleration indicates:
A. Coolant entering the combustion chamber
B. Excessive fuel delivery
C. Oil entering the combustion chamber
D. Lean air-fuel mixture
C. Oil entering the combustion chamber
Rationale: Blue smoke is a classic sign of engine oil being burned, often
from worn rings or valve seals.
3. A knocking noise that increases with engine load is MOST likely caused by:
A. Valve lash
B. Piston slap
C. Rod bearing wear
D. Timing chain slack
, C. Rod bearing wear
Rationale: Rod bearing knock is load-dependent and becomes louder
under acceleration.
4. Excessive crankcase pressure is commonly caused by:
A. Restricted exhaust
B. Worn piston rings
C. Lean mixture
D. Faulty thermostat
B. Worn piston rings
Rationale: Worn rings allow combustion gases to leak into the crankcase,
increasing pressure (blow-by).
5. Which tool is BEST for measuring cylinder taper?
A. Feeler gauge
B. Dial indicator
C. Micrometer
D. Dial bore gauge
D. Dial bore gauge
Rationale: A dial bore gauge accurately measures cylinder diameter
variations such as taper and out-of-round.
6. A ticking noise from the top of the engine is MOST likely due to:
A. Main bearing wear
B. Low oil pressure to lifters
C. Cracked piston
D. Bent connecting rod
B. Low oil pressure to lifters
Rationale: Hydraulic lifters tick when insufficient oil pressure prevents
proper lash compensation.
7. What condition can cause detonation?
A. Retarded ignition timing
B. Low compression ratio
C. Overheated combustion chamber
D. Rich air-fuel mixture
C. Overheated combustion chamber
, Rationale: Excessive heat can cause spontaneous combustion leading to
detonation (pinging).
8. A warped cylinder head is MOST often caused by:
A. Improper valve adjustment
B. Overheating
C. Low oil pressure
D. Carbon buildup
B. Overheating
Rationale: Excessive heat causes uneven expansion, leading to head
warpage.
9. When reinstalling main bearing caps, they should be:
A. Installed in any order
B. Torqued loosely
C. Installed in original positions
D. Replaced with new caps
C. Installed in original positions
Rationale: Main caps are line-bored with the block and must remain in
their original locations.
10.A burned exhaust valve is MOST likely caused by:
A. Rich mixture
B. Lean mixture
C. Low compression ratio
D. Excessive oil pressure
B. Lean mixture
Rationale: Lean mixtures raise combustion temperatures, damaging
exhaust valves.
11.What does a leak-down test measure?
A. Oil pressure
B. Fuel pressure
C. Cylinder sealing ability
D. Ignition timing
C. Cylinder sealing ability
ENGINE REPAIR PRACTICE EXAM
QUESTION AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A INSTANT DOWNLOAD PDF
1. A compression test shows one cylinder significantly lower than the others.
What is the MOST likely cause?
A. Faulty spark plug
B. Worn piston rings
C. Incorrect ignition timing
D. Restricted exhaust
B. Worn piston rings
Rationale: Low compression in a single cylinder commonly indicates worn
or damaged piston rings allowing pressure to leak past the piston.
2. Blue smoke from the exhaust during acceleration indicates:
A. Coolant entering the combustion chamber
B. Excessive fuel delivery
C. Oil entering the combustion chamber
D. Lean air-fuel mixture
C. Oil entering the combustion chamber
Rationale: Blue smoke is a classic sign of engine oil being burned, often
from worn rings or valve seals.
3. A knocking noise that increases with engine load is MOST likely caused by:
A. Valve lash
B. Piston slap
C. Rod bearing wear
D. Timing chain slack
, C. Rod bearing wear
Rationale: Rod bearing knock is load-dependent and becomes louder
under acceleration.
4. Excessive crankcase pressure is commonly caused by:
A. Restricted exhaust
B. Worn piston rings
C. Lean mixture
D. Faulty thermostat
B. Worn piston rings
Rationale: Worn rings allow combustion gases to leak into the crankcase,
increasing pressure (blow-by).
5. Which tool is BEST for measuring cylinder taper?
A. Feeler gauge
B. Dial indicator
C. Micrometer
D. Dial bore gauge
D. Dial bore gauge
Rationale: A dial bore gauge accurately measures cylinder diameter
variations such as taper and out-of-round.
6. A ticking noise from the top of the engine is MOST likely due to:
A. Main bearing wear
B. Low oil pressure to lifters
C. Cracked piston
D. Bent connecting rod
B. Low oil pressure to lifters
Rationale: Hydraulic lifters tick when insufficient oil pressure prevents
proper lash compensation.
7. What condition can cause detonation?
A. Retarded ignition timing
B. Low compression ratio
C. Overheated combustion chamber
D. Rich air-fuel mixture
C. Overheated combustion chamber
, Rationale: Excessive heat can cause spontaneous combustion leading to
detonation (pinging).
8. A warped cylinder head is MOST often caused by:
A. Improper valve adjustment
B. Overheating
C. Low oil pressure
D. Carbon buildup
B. Overheating
Rationale: Excessive heat causes uneven expansion, leading to head
warpage.
9. When reinstalling main bearing caps, they should be:
A. Installed in any order
B. Torqued loosely
C. Installed in original positions
D. Replaced with new caps
C. Installed in original positions
Rationale: Main caps are line-bored with the block and must remain in
their original locations.
10.A burned exhaust valve is MOST likely caused by:
A. Rich mixture
B. Lean mixture
C. Low compression ratio
D. Excessive oil pressure
B. Lean mixture
Rationale: Lean mixtures raise combustion temperatures, damaging
exhaust valves.
11.What does a leak-down test measure?
A. Oil pressure
B. Fuel pressure
C. Cylinder sealing ability
D. Ignition timing
C. Cylinder sealing ability
