ASE 1 - Engine Performance Practice 2023 Questions and
Answers with complete solution
2. A technician is checking for piston ring groove clearance. The proper technique
includes
A. The old ring and a feeler gauge.
B. The new ring and a feeler gauge.
C. Only a feeler gauge.
D. No feeler gauge is required.
Answer B is correct. Clean the pistons in a cold tank and then clean the grooves with a
ring groove cleaner before measuring.
3. A cylinder power balance test is being performed on a vehicle with sequential fuel
injection. The number five cylinder's rpm drop is less than all of the others. Technician A
says this could be the result of a restriction in the fuel injector. Technician B says this
could be caused by leaking secondary insulation. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer C is correct. Both restricted fuel injectors and leaking secondary wires will
reduce the cylinder's contribution. Anything that would have an affect on the cylinder's
power. It could be mechanical like a faulty valve, possibly the ignition, or the fuel mixture
affecting this cylinder's power output.
4. A turbocharger wastegate is sticking. Technician A says a stuck open wastegate will
result in overboost. Technician B says a stuck closed wastegate will result in an
underboost condition. Who is correct?
Neither technician is correct.
5. Technician A says a supercharger uses an intercooler to keep the engine's oil cool.
Technician B says intercoolers are used on turbochargers to keep the oil cool. Who is
correct?
Neither technician is correct.
6. A wet compression test is being performed on a four cylinder engine. The number
two cylinder's compression is below specifications and remains the same after injecting
oil. This result indicates:
A. Worn piston rings.
B. A faulty valve.
C. A hole in the piston.
D. Excessive carbon buildup on the piston's dome.
Answer A is wrong. If compression increases after injecting oil into the chamber, the
piston rings are worn. This is because the oil fills the gap caused by the worn rings
increasing the cylinder's compression.
Answer B is correct. If there is no change in compression after adding oil, the cylinder
has a faulty head gasket or valve.
,7. A vehicle has blue colored exhaust. Technician A says this may be caused by weak
piston rings. Technician B says this may be caused by a leaking fuel injector. Who is
correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer A is correct. Oil is burning in the combustion chamber causing blue colored
exhaust.
8. Technician A says to remove the ridge on the engine block before removing the
pistons. Technician B says a block's ridge will damage the new piston rings during
installation. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer C is correct. Remove the damaging ridge with a ridge reamer before removing
pistons. This also prevents damage to the new piston rings when it comes time to
reinstall the pistons.
9. A vehicle briefly blows blue/gray smoke from the tailpipe when it's first started in the
morning. The MOST likely cause of this condition is a:
A. Worn piston ring.
B. Lean fuel condition.
C. Leaking fuel injector.
D. Leaking valve seal.
Answer A is wrong. Worn piston rings would result in blue/gray smoke at all times, not
just in the mornings.
Answer B is wrong. Both a rich and a lean fuel condition will result in excessive HC's in
the emissions.
Answer C is wrong. A rich fuel condition will result in black smoke emitting from the
tailpipe.
Answer D is correct. A leaking valve seal will cause oil to leak into the cylinder's
chamber over time, usually overnight.
10. During a cylinder leakage test air bubbles appear in the neck of the radiator.
Technician A says a faulty intake valve will cause this condition. Technician B says a
crack in the engine block will cause this condition. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or
Answer A is wrong. A leaking intake valve will result in a hissing sound from the throttle
body. It can be heard by removing the air tube and opening the throttle plate. This is
because the intake valve is leaking air into the intake manifold.
, Answer B is correct. A crack in the blocks deck area or cylinder head allows
compression to leak into the coolant jacket. This results in air bubbles appearing in the
radiator neck.
11. After diagnosing and replacing the cooling system's water pump, the vehicle's
engine continues to overheat. Which of these is the MOST likely cause.
A. An air pocket in the system.
B. Leaking head gasket.
C. Faulty replacement water pump.
D. The radiator.
Answer A is correct. Air pockets occur after draining the engine's coolant. Some
vehicle's are more prone to this problem than others.
Answer B is wrong. A leaking head gasket would result in gases escaping the seal and
fluids such as coolant leaking in. The vehicle would likely emit white smoke from its
tailpipe as coolant burns in the combustion chamber.
Answer C is wrong. A faulty replacement water pump is not the most likely answer.
Answer D is wrong. The radiator is not the most likely answer. Answer A is correct.
12. Two technicians are discussing engine sealants and form in place gaskets.
Technician A says sealants such as RTV are aerobic. Technician B says some sensors
may be damaged if an unapproved sealant is used. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer A is wrong. Both technicians are correct. RTV (Room Temperature Vulcanizing)
is an aerobic sealant meaning that it cures in the presence of air.
Answer B is wrong. Both technicians are correct. Keep RTV away from sensors
Answer C is correct. Anaerobic sealers are usually used on smooth, machined
components. They dry in the absence of air.
Answer D is wrong. Both technicians are correct.
13. An engine has a noise that goes away as the engine warms and reaches operating
temperature. Which of these is the MOST likely cause.
A. Loose main bolt.
B. Loose connecting rod bolt.
C. Piston to wall clearance.
D. Loose intake manifold.
Answer A is wrong. A loose main bolt is not likely to go away as the engine reaches
operating temperature.
Answer B is wrong. A spun connecting rod bearing is not likely to go away as the engine
reaches operating temperature.
Answer C is correct. As the piston expands, the clearance between it and the cylinder
wall decreases, and so does the noise known as piston slap
Answer D is wrong. A loose intake manifold will cause low vacuum.
Answers with complete solution
2. A technician is checking for piston ring groove clearance. The proper technique
includes
A. The old ring and a feeler gauge.
B. The new ring and a feeler gauge.
C. Only a feeler gauge.
D. No feeler gauge is required.
Answer B is correct. Clean the pistons in a cold tank and then clean the grooves with a
ring groove cleaner before measuring.
3. A cylinder power balance test is being performed on a vehicle with sequential fuel
injection. The number five cylinder's rpm drop is less than all of the others. Technician A
says this could be the result of a restriction in the fuel injector. Technician B says this
could be caused by leaking secondary insulation. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer C is correct. Both restricted fuel injectors and leaking secondary wires will
reduce the cylinder's contribution. Anything that would have an affect on the cylinder's
power. It could be mechanical like a faulty valve, possibly the ignition, or the fuel mixture
affecting this cylinder's power output.
4. A turbocharger wastegate is sticking. Technician A says a stuck open wastegate will
result in overboost. Technician B says a stuck closed wastegate will result in an
underboost condition. Who is correct?
Neither technician is correct.
5. Technician A says a supercharger uses an intercooler to keep the engine's oil cool.
Technician B says intercoolers are used on turbochargers to keep the oil cool. Who is
correct?
Neither technician is correct.
6. A wet compression test is being performed on a four cylinder engine. The number
two cylinder's compression is below specifications and remains the same after injecting
oil. This result indicates:
A. Worn piston rings.
B. A faulty valve.
C. A hole in the piston.
D. Excessive carbon buildup on the piston's dome.
Answer A is wrong. If compression increases after injecting oil into the chamber, the
piston rings are worn. This is because the oil fills the gap caused by the worn rings
increasing the cylinder's compression.
Answer B is correct. If there is no change in compression after adding oil, the cylinder
has a faulty head gasket or valve.
,7. A vehicle has blue colored exhaust. Technician A says this may be caused by weak
piston rings. Technician B says this may be caused by a leaking fuel injector. Who is
correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer A is correct. Oil is burning in the combustion chamber causing blue colored
exhaust.
8. Technician A says to remove the ridge on the engine block before removing the
pistons. Technician B says a block's ridge will damage the new piston rings during
installation. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer C is correct. Remove the damaging ridge with a ridge reamer before removing
pistons. This also prevents damage to the new piston rings when it comes time to
reinstall the pistons.
9. A vehicle briefly blows blue/gray smoke from the tailpipe when it's first started in the
morning. The MOST likely cause of this condition is a:
A. Worn piston ring.
B. Lean fuel condition.
C. Leaking fuel injector.
D. Leaking valve seal.
Answer A is wrong. Worn piston rings would result in blue/gray smoke at all times, not
just in the mornings.
Answer B is wrong. Both a rich and a lean fuel condition will result in excessive HC's in
the emissions.
Answer C is wrong. A rich fuel condition will result in black smoke emitting from the
tailpipe.
Answer D is correct. A leaking valve seal will cause oil to leak into the cylinder's
chamber over time, usually overnight.
10. During a cylinder leakage test air bubbles appear in the neck of the radiator.
Technician A says a faulty intake valve will cause this condition. Technician B says a
crack in the engine block will cause this condition. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or
Answer A is wrong. A leaking intake valve will result in a hissing sound from the throttle
body. It can be heard by removing the air tube and opening the throttle plate. This is
because the intake valve is leaking air into the intake manifold.
, Answer B is correct. A crack in the blocks deck area or cylinder head allows
compression to leak into the coolant jacket. This results in air bubbles appearing in the
radiator neck.
11. After diagnosing and replacing the cooling system's water pump, the vehicle's
engine continues to overheat. Which of these is the MOST likely cause.
A. An air pocket in the system.
B. Leaking head gasket.
C. Faulty replacement water pump.
D. The radiator.
Answer A is correct. Air pockets occur after draining the engine's coolant. Some
vehicle's are more prone to this problem than others.
Answer B is wrong. A leaking head gasket would result in gases escaping the seal and
fluids such as coolant leaking in. The vehicle would likely emit white smoke from its
tailpipe as coolant burns in the combustion chamber.
Answer C is wrong. A faulty replacement water pump is not the most likely answer.
Answer D is wrong. The radiator is not the most likely answer. Answer A is correct.
12. Two technicians are discussing engine sealants and form in place gaskets.
Technician A says sealants such as RTV are aerobic. Technician B says some sensors
may be damaged if an unapproved sealant is used. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither A or B
Answer A is wrong. Both technicians are correct. RTV (Room Temperature Vulcanizing)
is an aerobic sealant meaning that it cures in the presence of air.
Answer B is wrong. Both technicians are correct. Keep RTV away from sensors
Answer C is correct. Anaerobic sealers are usually used on smooth, machined
components. They dry in the absence of air.
Answer D is wrong. Both technicians are correct.
13. An engine has a noise that goes away as the engine warms and reaches operating
temperature. Which of these is the MOST likely cause.
A. Loose main bolt.
B. Loose connecting rod bolt.
C. Piston to wall clearance.
D. Loose intake manifold.
Answer A is wrong. A loose main bolt is not likely to go away as the engine reaches
operating temperature.
Answer B is wrong. A spun connecting rod bearing is not likely to go away as the engine
reaches operating temperature.
Answer C is correct. As the piston expands, the clearance between it and the cylinder
wall decreases, and so does the noise known as piston slap
Answer D is wrong. A loose intake manifold will cause low vacuum.
