ASE A1 (Engine Repair)
Practice Test - Cumulative fully
solved & updated (latest
version)
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:
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
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 - answer small leak in exhaust manifold
-intake manifold leak causes a high-pitched whistle at idle and low speeds
-carb choke stuck closed will not cause a high-pitched whistle
-fuel system leak normally would not cause a noise
a heavy thumping noise occurs with the engine idling, but the oil pressure is
normal. this may be caused by:
worn pistons and cylinders,
loose flywheel bolts,
worm main bearings,
loose camshaft bearings, - answer loose flywheel bolts
Practice Test - Cumulative fully
solved & updated (latest
version)
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:
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
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 - answer small leak in exhaust manifold
-intake manifold leak causes a high-pitched whistle at idle and low speeds
-carb choke stuck closed will not cause a high-pitched whistle
-fuel system leak normally would not cause a noise
a heavy thumping noise occurs with the engine idling, but the oil pressure is
normal. this may be caused by:
worn pistons and cylinders,
loose flywheel bolts,
worm main bearings,
loose camshaft bearings, - answer loose flywheel bolts
