A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
All of the following are tests performed on the PCV system EXCEPT:
A. The rattle test
B. The snap- back test
C. Crankcase vacuum test
D. Blowby test -
correct answer ✅D. The PCV valve should rattle when shaken back
and forth.
When the thumb is placed over the end of the PCV valve with the
engine idling, the plunger should snap back.
A water manometer can be used to check the crankcase for vacuum
at idle.
There is no blowby test that is performed on the PCV system.
Which of the following is the LEAST LIKELY cause of ignition module
failure?
A. An open spark plug wire
B. No dielectric grease under the module
C. A fouled spark plug
,A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
D. Loose module mounting screws -
correct answer ✅C. Faulty secondary ignition components are
common causes of ignition module failure.
Some modules require the use of dielectric grease to aid in
dissipating heat.
A fouled spark plug would cause an engine miss, but would not
cause the ignition module to fail.
Loose module mounting screws will cause the module to fail
prematurely.
A sequential fuel- injected vehicle has poor fuel economy, yet starts
and runs fine. Technician A says the fuel return line may be partially
restricted. Technician B says the fuel pressure regulator may be
stuck open. Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅A. A partially restricted fuel return hose would
cause the fuel pressure to be higher than it should. This would
cause poor fuel economy without affecting drivability.
,A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
A stuck open fuel regulator would lower fuel pressure, possibly
causing a no-start, but would not cause a fuel economy complaint.
Technician A says if the passages in the exhaust gas recirculation
(EGR) system get plugged up with carbon, then the engine could
spark knock. Technician B says if the EGR passages get plugged up,
then the engine will not run hot enough for complete combustion.
Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅A. The EGR system is used to lower combustion
chamber temperature . If the EGR system does not operate, then
the engine will operate too hot, causing spark knock and elevated
oxides of nitrogen (NOx) reading.
An inoperative EGR system will raise combustion chamber
temperatures and cause the engine to run hotter.
Technician A says a coil with weak reserve voltage could cause a
miss under acceleration. Technician B says the ignition coil only
, A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
produces enough secondary voltage to jump the spark plug gap.
Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅C. Both. When the power transistor in the
ignition control module opens the primary ignition circuit, the
build-up magnetic field in the coil collapses. This produces the
secondary voltage to jump the gap at the spark plug. The voltage
that the coil produces can be broken down into three different
types: "required voltage" (the voltage required to jump the gap at
the spark plug), "available voltage" (the voltage available to jump
the gap at the spark plug), and the "reserve voltage" (the voltage in
reserve after the spark plug fires). As the engine accelerates, the
required voltage goes up. If there is not enough voltage in reserve,
then the engine will miss.
Which of the following is the very first step a technician should take
when performing a diagnostic procedure?
A. Perform simple tests
B. Retrieve diagnostic trouble codes (DTCs)
Exam Questions & Answers (Grade
A+)
All of the following are tests performed on the PCV system EXCEPT:
A. The rattle test
B. The snap- back test
C. Crankcase vacuum test
D. Blowby test -
correct answer ✅D. The PCV valve should rattle when shaken back
and forth.
When the thumb is placed over the end of the PCV valve with the
engine idling, the plunger should snap back.
A water manometer can be used to check the crankcase for vacuum
at idle.
There is no blowby test that is performed on the PCV system.
Which of the following is the LEAST LIKELY cause of ignition module
failure?
A. An open spark plug wire
B. No dielectric grease under the module
C. A fouled spark plug
,A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
D. Loose module mounting screws -
correct answer ✅C. Faulty secondary ignition components are
common causes of ignition module failure.
Some modules require the use of dielectric grease to aid in
dissipating heat.
A fouled spark plug would cause an engine miss, but would not
cause the ignition module to fail.
Loose module mounting screws will cause the module to fail
prematurely.
A sequential fuel- injected vehicle has poor fuel economy, yet starts
and runs fine. Technician A says the fuel return line may be partially
restricted. Technician B says the fuel pressure regulator may be
stuck open. Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅A. A partially restricted fuel return hose would
cause the fuel pressure to be higher than it should. This would
cause poor fuel economy without affecting drivability.
,A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
A stuck open fuel regulator would lower fuel pressure, possibly
causing a no-start, but would not cause a fuel economy complaint.
Technician A says if the passages in the exhaust gas recirculation
(EGR) system get plugged up with carbon, then the engine could
spark knock. Technician B says if the EGR passages get plugged up,
then the engine will not run hot enough for complete combustion.
Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅A. The EGR system is used to lower combustion
chamber temperature . If the EGR system does not operate, then
the engine will operate too hot, causing spark knock and elevated
oxides of nitrogen (NOx) reading.
An inoperative EGR system will raise combustion chamber
temperatures and cause the engine to run hotter.
Technician A says a coil with weak reserve voltage could cause a
miss under acceleration. Technician B says the ignition coil only
, A8 Engine Performance Practice Test
Exam Questions & Answers (Grade
A+)
produces enough secondary voltage to jump the spark plug gap.
Who is correct?
A. Tech A
B. Tech B
C. Both technicians
D. Neither technician -
correct answer ✅C. Both. When the power transistor in the
ignition control module opens the primary ignition circuit, the
build-up magnetic field in the coil collapses. This produces the
secondary voltage to jump the gap at the spark plug. The voltage
that the coil produces can be broken down into three different
types: "required voltage" (the voltage required to jump the gap at
the spark plug), "available voltage" (the voltage available to jump
the gap at the spark plug), and the "reserve voltage" (the voltage in
reserve after the spark plug fires). As the engine accelerates, the
required voltage goes up. If there is not enough voltage in reserve,
then the engine will miss.
Which of the following is the very first step a technician should take
when performing a diagnostic procedure?
A. Perform simple tests
B. Retrieve diagnostic trouble codes (DTCs)
