ASE A1 (Engine Repair) Practice Test –
Cumulative 2025/2026 Exam Questions
and Answers | 100% Solved
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,
A & B,
Neither . - 🧠 ANSWER ✔✔A only:
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1
,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
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, - 🧠 ANSWER ✔✔worn piston rings
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
2
,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.
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, - 🧠 ANSWER ✔✔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.
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.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, Tech B says the engine may have an intake manifold vacuum leak.
A only,
B only,
A & B,
Neither , - 🧠 ANSWER ✔✔Both A&B
Both a misfiring ignition system and an intake manifold leak could cause a
cylinder to contribute too little power
while discussing basic diagnostic procedures,
Tech A says the most complicated diagnostic tests should be performed
first. Tech B says that you should first question the customer to obtain as
much info as possible about the problem
A,
B,
A & B,
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
4
Cumulative 2025/2026 Exam Questions
and Answers | 100% Solved
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,
A & B,
Neither . - 🧠 ANSWER ✔✔A only:
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
1
,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
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, - 🧠 ANSWER ✔✔worn piston rings
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
2
,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.
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, - 🧠 ANSWER ✔✔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.
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.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
3
, Tech B says the engine may have an intake manifold vacuum leak.
A only,
B only,
A & B,
Neither , - 🧠 ANSWER ✔✔Both A&B
Both a misfiring ignition system and an intake manifold leak could cause a
cylinder to contribute too little power
while discussing basic diagnostic procedures,
Tech A says the most complicated diagnostic tests should be performed
first. Tech B says that you should first question the customer to obtain as
much info as possible about the problem
A,
B,
A & B,
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
4
