ASE A1 (ENGINE
REPAIR) PRACTICE
TEST –
CUMULATIVE
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 . - answers -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, - answers -worn piston rings
When using a compression tester, the readings on the cylinders are all even, but lower
than spec. This could indicate:
Blown head gasket,
,Carbon buildup,
Cracked head,
Worn rings and cylinders, - answers -worn rings and cylinders
-a low reading on two adjacent cylinders may indicate a blown head gasket
-carbon buildup would cause a high reading
-a low reading on two adjacent cylinders may indicate a cracked head
A cylinder balance test is being performed on an engine to determine which cylinder is
causing a miss.
Tech a says that when the faulty cylinder is disabled, engine rpm will drop more than for
the other cylinders.
Tech b says disabling the faulty cylinder will cause the engine to stall
A,
B,
Both,
Neither, - answers -neither
The faulty cylinder will not cause the engine to stall, neither will it cause the engine to
drop in rpm since it is faulty.
An engine is idling at 750 rpm. The pointer on the vacuum gauge is floating between 11
and 16 in hg. The most likely cause is
Retarded timing,
Advanced timing,
Stuch egr valve,
Too lean idle mixture, - answers -too lean idle mixture
All others would not result in gauge fluctuation
The first step a tech should take for diagnosis is:
Think of possible causes of the problem,
Question the customer,
Road test the vehicle,
Listen to the customer, - answers -listen to the customer
The customer says that the engine requires excessive cranking to start. The least likely
cause of this problem would be:
Cracked cylinder block,
Jumped timing belt,
Faulty fuel pump,
Stuck-open egr valve, - answers -cracked cylinder block
,Which of the following is least likely to cause engine noise?
Loose pistons,
Worn cylinders,
Worn main bearings,
Loose camshaft bearings, - answers -loose cam bearings
-loose pistons may cause a rapping noise while accel
-worn cylinders may cause a rapping noise while accel
-worn main bearings may cause a thumping noise when starting
The least likely first step in a diagnosis would be to:
Question the customer for more info,
Be sure that the customer complaint is eliminated
Start with the most difficult test
Road test the vehicle - answers -start with the most difficult test
A cylinder balance test on a carbureted engine has revealed one cylinder is contributing
less power than the others. The least likely cause of this is:
Faulty ignition system
Burned exhaust valve
Faulty carburetor
Leaking intake manifold - answers -faulty carburetor
-faulty ignition system, burned exhaust valve, and leaking intake manifold are likely to
cause one cylinder to provide less power than others. The carburetor would not cause
one single cylinder to contribute less power.
An excessive sulfur smell in the exhaust with a cat can be an indication of:
Lean fuel mixture
Coolant leaking into combustion chamber
Rich fuel mixture
Vacuum leak - answers -rich fuel mixture
-lean fuel mixture would not cause a sulfur smell
-coolant leaking into the chamber would cause a gray exhaust color
-a vacuum leak would cause a rough idle that would decrease as engine speed
increases
A low, steady vacuum gauge reading from 11 to 15 indicates:
Burned or leaking valves
, Late ignition timing
Weak valve springs
Leaking head gasket - answers -late ignition timing
-burned or leaking valves cause a fluctuation between 12 and 18
-weak valve springs cause a fluctuation between 10 and 25
-leaking head gasket would cause a fluctuation between 7 and 20
During a cylinder leakage test using a cylinder leakage tester, the reading exceeds
20%. The least likely place the tech would for leaking air would be:
Tool air hose
Vehicle tailpipe
Radiator filter neck
Pcv valve opening in the rocker arm cover - answers -tool air hose
-leaking exhaust valve would cause air to escape through the tailpipe
-a leaking head gasket or cracked head would cause air to escape from the radiator
filler neck
-worn piston rings would cause air to escape from the opening in the rocker arm cover
During a cylinder leakage test, air comes out of the pcv valve opening in the rocker arm
cover. This is an indication of:
Worn intake valves
Worn exhaust valves
A broken pcv valve
Worn piston rings - answers -worn piston rings
-worn intake valves would cause air leaks at the throttle body or carburetor
-worn exhaust valves would cause air to leak at the tailpipe
-a broken pcv valve wouldn't cause an air leak
Even a small oil leak can result in major oil loss. It has been estimated that three drops
of oil leaking every 100 feet results in a total of 3 quarts (2.8 liters) of oil loss every
100 miles
500 miles
1500 miles
1000 miles - answers -1000 miles
If the starter motor does not crank the engine, the first diagnostic step a tech should
take is:
Disable the ignition system
Remove the spark plugs
REPAIR) PRACTICE
TEST –
CUMULATIVE
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 . - answers -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, - answers -worn piston rings
When using a compression tester, the readings on the cylinders are all even, but lower
than spec. This could indicate:
Blown head gasket,
,Carbon buildup,
Cracked head,
Worn rings and cylinders, - answers -worn rings and cylinders
-a low reading on two adjacent cylinders may indicate a blown head gasket
-carbon buildup would cause a high reading
-a low reading on two adjacent cylinders may indicate a cracked head
A cylinder balance test is being performed on an engine to determine which cylinder is
causing a miss.
Tech a says that when the faulty cylinder is disabled, engine rpm will drop more than for
the other cylinders.
Tech b says disabling the faulty cylinder will cause the engine to stall
A,
B,
Both,
Neither, - answers -neither
The faulty cylinder will not cause the engine to stall, neither will it cause the engine to
drop in rpm since it is faulty.
An engine is idling at 750 rpm. The pointer on the vacuum gauge is floating between 11
and 16 in hg. The most likely cause is
Retarded timing,
Advanced timing,
Stuch egr valve,
Too lean idle mixture, - answers -too lean idle mixture
All others would not result in gauge fluctuation
The first step a tech should take for diagnosis is:
Think of possible causes of the problem,
Question the customer,
Road test the vehicle,
Listen to the customer, - answers -listen to the customer
The customer says that the engine requires excessive cranking to start. The least likely
cause of this problem would be:
Cracked cylinder block,
Jumped timing belt,
Faulty fuel pump,
Stuck-open egr valve, - answers -cracked cylinder block
,Which of the following is least likely to cause engine noise?
Loose pistons,
Worn cylinders,
Worn main bearings,
Loose camshaft bearings, - answers -loose cam bearings
-loose pistons may cause a rapping noise while accel
-worn cylinders may cause a rapping noise while accel
-worn main bearings may cause a thumping noise when starting
The least likely first step in a diagnosis would be to:
Question the customer for more info,
Be sure that the customer complaint is eliminated
Start with the most difficult test
Road test the vehicle - answers -start with the most difficult test
A cylinder balance test on a carbureted engine has revealed one cylinder is contributing
less power than the others. The least likely cause of this is:
Faulty ignition system
Burned exhaust valve
Faulty carburetor
Leaking intake manifold - answers -faulty carburetor
-faulty ignition system, burned exhaust valve, and leaking intake manifold are likely to
cause one cylinder to provide less power than others. The carburetor would not cause
one single cylinder to contribute less power.
An excessive sulfur smell in the exhaust with a cat can be an indication of:
Lean fuel mixture
Coolant leaking into combustion chamber
Rich fuel mixture
Vacuum leak - answers -rich fuel mixture
-lean fuel mixture would not cause a sulfur smell
-coolant leaking into the chamber would cause a gray exhaust color
-a vacuum leak would cause a rough idle that would decrease as engine speed
increases
A low, steady vacuum gauge reading from 11 to 15 indicates:
Burned or leaking valves
, Late ignition timing
Weak valve springs
Leaking head gasket - answers -late ignition timing
-burned or leaking valves cause a fluctuation between 12 and 18
-weak valve springs cause a fluctuation between 10 and 25
-leaking head gasket would cause a fluctuation between 7 and 20
During a cylinder leakage test using a cylinder leakage tester, the reading exceeds
20%. The least likely place the tech would for leaking air would be:
Tool air hose
Vehicle tailpipe
Radiator filter neck
Pcv valve opening in the rocker arm cover - answers -tool air hose
-leaking exhaust valve would cause air to escape through the tailpipe
-a leaking head gasket or cracked head would cause air to escape from the radiator
filler neck
-worn piston rings would cause air to escape from the opening in the rocker arm cover
During a cylinder leakage test, air comes out of the pcv valve opening in the rocker arm
cover. This is an indication of:
Worn intake valves
Worn exhaust valves
A broken pcv valve
Worn piston rings - answers -worn piston rings
-worn intake valves would cause air leaks at the throttle body or carburetor
-worn exhaust valves would cause air to leak at the tailpipe
-a broken pcv valve wouldn't cause an air leak
Even a small oil leak can result in major oil loss. It has been estimated that three drops
of oil leaking every 100 feet results in a total of 3 quarts (2.8 liters) of oil loss every
100 miles
500 miles
1500 miles
1000 miles - answers -1000 miles
If the starter motor does not crank the engine, the first diagnostic step a tech should
take is:
Disable the ignition system
Remove the spark plugs
