ASE A1 COMPREHENSIVE TEST BANK 2026
VERIFIED QUESTIONS AND SOLUTIONS
100% CORRECT
●● 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
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.
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,
Neither,.
Answer: B
Always attempt the more simple diagnosis first
●● with the engine idling, a vacuum gauge connected to the intake
manifold fluctuates (from 15 to 20). These fluctuations may be caused
by
late ignition timing,
intake manifold vacuum leaks,
a restricted exhaust system,
sticky valve stems and guides,.
Answer: sticky valve stems and guides
, -late ignition timing would result in a low, steady reading
-intake manifold leaks would cause a very low, steady reading
-a restricted exhaust system would cause vacuum to slowly decrease
after the engine was accelerated and held steady
●● oil is leaking from the crankshaft rear main bearing seal on an
engine. Tech A says the oil seal could be faulty. Tech B says the PCV
system may not be functioning.
A,
B,
A & B,
Neither,.
Answer: A&B
●● A high-pitched squealing noise is heard during hard acceleration.
This may be the cause of:
intake manifold leak,
the choke stuck closed
fuel system leak
small leak in exhaust manifold.
VERIFIED QUESTIONS AND SOLUTIONS
100% CORRECT
●● 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
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.
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,
Neither,.
Answer: B
Always attempt the more simple diagnosis first
●● with the engine idling, a vacuum gauge connected to the intake
manifold fluctuates (from 15 to 20). These fluctuations may be caused
by
late ignition timing,
intake manifold vacuum leaks,
a restricted exhaust system,
sticky valve stems and guides,.
Answer: sticky valve stems and guides
, -late ignition timing would result in a low, steady reading
-intake manifold leaks would cause a very low, steady reading
-a restricted exhaust system would cause vacuum to slowly decrease
after the engine was accelerated and held steady
●● oil is leaking from the crankshaft rear main bearing seal on an
engine. Tech A says the oil seal could be faulty. Tech B says the PCV
system may not be functioning.
A,
B,
A & B,
Neither,.
Answer: A&B
●● A high-pitched squealing noise is heard during hard acceleration.
This may be the cause of:
intake manifold leak,
the choke stuck closed
fuel system leak
small leak in exhaust manifold.
