ASE A1 - PRACTICE TEST (SECTION A)
EXAM 2025 QUESTIONS AND ANSWERS
1. an engine miss is being diagnosed using a cylinder leakage test. Technician A says that any
cylinder with over 20% leakage has excessive leakage. Tech B says that air leaking from the
tailpipe indicates a cracked cylinder.
A only
B only
Both A & B
Neither A nor B - ANS A only
If cylinder leakage exceeds 20%, check for air escaping the tailpipe, the PCV valve opening in
the rocker arm cover, and the top of the throttle body or carburetor.
Air leaking from the tailpipe usually indicates an exhaust valve leak
23. during a compression test, a cylinder has 40% of the specified compression reading. When
the tech performs a wet test, the compression reading on this cylinder has 75% of the specified
reading. The cause of the low compression reading could be
worn piston rings
a burned exhaust valve
a bent intake valve
a worn camshaft lobe - ANS worn piston rings
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, if compression increases during a wet test, this indicates worn piston rings. Compression would
not increase if an exhaust valve is burned, intake valve is bent, or camshaft lobe is worn.
35. the customer complains that the engine cranks but does not start; the first thing to check
should be
valve train operation
battery voltage
compression
engine vacuum - ANS valve train operation
if the engine cranks properly, the battery is not the problem. Compression would not be the
FIRST test, and because engine vacuum is low during a crank, a vacuum test would not be
conclusive.
40. during a cylinder balance test on an engine with fuel injection, one cylinder provides very
little rpm drop. Tech A says the ignition system may be misfiring on that cylinder. Tech B says
the engine may have an intake manifold vacuum leak.
A only
B only
Both A & B
Neither A nor B - ANS Both A&B
Both a misfiring ignition system and an intake manifold leak could cause a cylinder to contribute
too little power
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 2
EXAM 2025 QUESTIONS AND ANSWERS
1. an engine miss is being diagnosed using a cylinder leakage test. Technician A says that any
cylinder with over 20% leakage has excessive leakage. Tech B says that air leaking from the
tailpipe indicates a cracked cylinder.
A only
B only
Both A & B
Neither A nor B - ANS A only
If cylinder leakage exceeds 20%, check for air escaping the tailpipe, the PCV valve opening in
the rocker arm cover, and the top of the throttle body or carburetor.
Air leaking from the tailpipe usually indicates an exhaust valve leak
23. during a compression test, a cylinder has 40% of the specified compression reading. When
the tech performs a wet test, the compression reading on this cylinder has 75% of the specified
reading. The cause of the low compression reading could be
worn piston rings
a burned exhaust valve
a bent intake valve
a worn camshaft lobe - ANS worn piston rings
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 1
, if compression increases during a wet test, this indicates worn piston rings. Compression would
not increase if an exhaust valve is burned, intake valve is bent, or camshaft lobe is worn.
35. the customer complains that the engine cranks but does not start; the first thing to check
should be
valve train operation
battery voltage
compression
engine vacuum - ANS valve train operation
if the engine cranks properly, the battery is not the problem. Compression would not be the
FIRST test, and because engine vacuum is low during a crank, a vacuum test would not be
conclusive.
40. during a cylinder balance test on an engine with fuel injection, one cylinder provides very
little rpm drop. Tech A says the ignition system may be misfiring on that cylinder. Tech B says
the engine may have an intake manifold vacuum leak.
A only
B only
Both A & B
Neither A nor B - ANS Both A&B
Both a misfiring ignition system and an intake manifold leak could cause a cylinder to contribute
too little power
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 2
