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ASE A1- Engine Repair Questions and
Correct Answers/ Latest Update / Already
Graded
A compression test shows that one cylinder is too low. A leakage test
on that cylinder shows that there is excessive leakage. During the test,
air could be heard coming from the tailpipe. Which of the following
could be the cause?
A. Broken piston rings
B. Bad head gasket
C. Bad exhaust gasket
D. An exhaust valve not seating
Ans: The correct answer is D. If an exhaust valve is not seating,
air will leak from the combustion chamber by way of the valve
out to the tailpipe and make an audible sound. Broken rings or a
bad head gasket would have air leaking through the oil filler or
cooling system.
Technician A says that main bearing oil clearance can be checked with
plastigage. Technician B says that main bearing oil clearance can be
checked with a dial bore gauge. Who is right?
A. Technician A only
B. Technician B only
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C. Both A and B
D. Neither A or B
Ans: The correct answer is C, both technicians are right. Either
method can be used to check main bearing oil clearance.
Which of the following is NOT a method of correcting excessive valve
stem-to-guide clearance?
A. Knurling the valve stem
B. Knurling the guide
C. Reaming for oversize
D. Guide replacement
Ans: The correct answer is A. The valve stem is hardened and
cannot be knurled.
A vacuum gauge is connected to the intake manifold of an engine
running at idle. The pointer on the gauge fluctuates rapidly but
steadies as the engine speed is increased. The test results indicate:
A. A leaking intake manifold gasket
B. Worn valve guides
C. Late ignition timing
D. A weak valve spring
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Ans: The correct answer is B. Worn valve guide could cause the
needle to fluctuate rapidly at idle but steady as the engine
speed is increased. A leaking intake manifold gasket or late
ignition timing would cause a steady low reading. A weak va lve
spring would cause the gauge needle to fluctuate as engine
speed increased.
A technician takes a compression reading on a 4-cylinder engine, and
gets readings of 140, 135, 135, and 40 psi. Then he preforms a wet
compression test, and the readings are almost the same as those in the
first test. Technician A says that a burned valve could cause these
readings. Technician B says that a broken piston ring could cause these
readings. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Ans: The correct answer is A, only technician A is correct. A
burned valve will not allow the cylinder to build compression,
and the results from wet and dry compression tests will be the
same. If piston rings (or worn cylinder walls) were at fault,
compression readings from a wet test would exceed dry test
results.
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Technician A says that retarded valve timing can cause high cylinder
compression readings. Technician B says that a lean air/fuel mixture
can cause a high intake manifold vacuum reading. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Ans: The correct answer is D, neither technician is right.
Technician A is wrong because retarded valve timing will cause
the valves to open and close at the wrong time, thereby
reducing compression and manifold vacuum readings. Retarded
valve timing can be caused by a loose timing belt or chain
jumping one or more teeth. Technician B is wrong because a
low but steady manifold vacuum reading may be caused by a
lean air/fuel mixture. Air leaks or vacuum leaks can cause a lean
condition and are common causes of rough idle, hesitation,
stalling and hard starting. If the mixture is artificially enriched
by injecting propane into the induction system, and engine
running lean should speed up and the vacuum reading should
rise.
An engine is being rebuilt and the crankshaft connecting rod journals
have been ground undersize. Specifications show that the original
connecting rod journal size was 2.1228-in. 2.1236-in. If the journals now
measure 2.1032-in., what size bearings should be used?
All rights reserved © 2025/ 2026 |
ASE A1- Engine Repair Questions and
Correct Answers/ Latest Update / Already
Graded
A compression test shows that one cylinder is too low. A leakage test
on that cylinder shows that there is excessive leakage. During the test,
air could be heard coming from the tailpipe. Which of the following
could be the cause?
A. Broken piston rings
B. Bad head gasket
C. Bad exhaust gasket
D. An exhaust valve not seating
Ans: The correct answer is D. If an exhaust valve is not seating,
air will leak from the combustion chamber by way of the valve
out to the tailpipe and make an audible sound. Broken rings or a
bad head gasket would have air leaking through the oil filler or
cooling system.
Technician A says that main bearing oil clearance can be checked with
plastigage. Technician B says that main bearing oil clearance can be
checked with a dial bore gauge. Who is right?
A. Technician A only
B. Technician B only
All rights reserved © 2025/ 2026 |
, Page |2
C. Both A and B
D. Neither A or B
Ans: The correct answer is C, both technicians are right. Either
method can be used to check main bearing oil clearance.
Which of the following is NOT a method of correcting excessive valve
stem-to-guide clearance?
A. Knurling the valve stem
B. Knurling the guide
C. Reaming for oversize
D. Guide replacement
Ans: The correct answer is A. The valve stem is hardened and
cannot be knurled.
A vacuum gauge is connected to the intake manifold of an engine
running at idle. The pointer on the gauge fluctuates rapidly but
steadies as the engine speed is increased. The test results indicate:
A. A leaking intake manifold gasket
B. Worn valve guides
C. Late ignition timing
D. A weak valve spring
All rights reserved © 2025/ 2026 |
, Page |3
Ans: The correct answer is B. Worn valve guide could cause the
needle to fluctuate rapidly at idle but steady as the engine
speed is increased. A leaking intake manifold gasket or late
ignition timing would cause a steady low reading. A weak va lve
spring would cause the gauge needle to fluctuate as engine
speed increased.
A technician takes a compression reading on a 4-cylinder engine, and
gets readings of 140, 135, 135, and 40 psi. Then he preforms a wet
compression test, and the readings are almost the same as those in the
first test. Technician A says that a burned valve could cause these
readings. Technician B says that a broken piston ring could cause these
readings. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Ans: The correct answer is A, only technician A is correct. A
burned valve will not allow the cylinder to build compression,
and the results from wet and dry compression tests will be the
same. If piston rings (or worn cylinder walls) were at fault,
compression readings from a wet test would exceed dry test
results.
All rights reserved © 2025/ 2026 |
, Page |4
Technician A says that retarded valve timing can cause high cylinder
compression readings. Technician B says that a lean air/fuel mixture
can cause a high intake manifold vacuum reading. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
Ans: The correct answer is D, neither technician is right.
Technician A is wrong because retarded valve timing will cause
the valves to open and close at the wrong time, thereby
reducing compression and manifold vacuum readings. Retarded
valve timing can be caused by a loose timing belt or chain
jumping one or more teeth. Technician B is wrong because a
low but steady manifold vacuum reading may be caused by a
lean air/fuel mixture. Air leaks or vacuum leaks can cause a lean
condition and are common causes of rough idle, hesitation,
stalling and hard starting. If the mixture is artificially enriched
by injecting propane into the induction system, and engine
running lean should speed up and the vacuum reading should
rise.
An engine is being rebuilt and the crankshaft connecting rod journals
have been ground undersize. Specifications show that the original
connecting rod journal size was 2.1228-in. 2.1236-in. If the journals now
measure 2.1032-in., what size bearings should be used?
All rights reserved © 2025/ 2026 |
