ENGINE REPAIR MICHIGAN MECHANIC STUDY
GUIDE – Questions And Solutions
Section 1: General Engine Knowledge & Diagnosis (20 Questions)
1. What is the primary purpose of the oil pump?
a) To filter the oil
b) To cool the oil
c) To create oil pressure and circulate oil
d) To store the oil
2. A "ticking" noise that increases with engine RPM is most likely caused by:
a) A worn rod bearing
b) A spun main bearing
c) A collapsed piston skirt
d) A faulty hydraulic lifter or low oil pressure
3. The term "engine displacement" refers to:
a) The physical size of the engine block
b) The total weight of the engine
c) The total volume swept by all the pistons
d) The distance the piston travels
4. A compression test reveals one cylinder is significantly lower than the others. A wet
compression test brings the compression back to normal. This indicates a problem with:
a) The valvetrain
b) The piston rings
c) A cracked cylinder head
d) The ignition system
5. A engine with a "knocking" noise that is deepest and loudest under load is likely suffering
from:
a) Piston slap
b) Detonation (spark knock)
c) A faulty water pump
d) A loose accessory belt
6. The Powertrain Control Module (PCM) uses input from this sensor to determine engine
load for fuel delivery and spark timing.
,a) Coolant Temperature Sensor (ECT)
b) Throttle Position Sensor (TPS)
c) Mass Air Flow (MAF) Sensor
d) Camshaft Position Sensor (CMP)
7. A P0302 diagnostic trouble code indicates a misfire in:
a) Cylinder #2
b) Bank 2
c) Cylinder #3
d) A random cylinder
8. The most likely cause of blue/gray exhaust smoke is:
a) An overly rich air/fuel mixture
b) Coolant entering the combustion chamber
c) Oil entering the combustion chamber and being burned
d) Normal condensation burn-off
9. A "lean" air/fuel mixture can cause:
a) Engine dieseling (run-on)
b) Fouled spark plugs
c) High HC and NOx emissions, and engine overheating
d) Black, sooty exhaust smoke
10. The purpose of a "vacuum test" on an engine is to check for problems related to:
a) Electrical charging system
b) Engine sealing and mechanical condition
c) Transmission fluid pressure
d) Power steering operation
11. A vehicle has a persistent overheating issue only at highway speeds. The most likely cause
is:
a) A faulty thermostat stuck closed
b) A clogged radiator
c) A faulty cooling fan clutch
d) A low coolant level
12. The catalytic converter is designed to reduce which tailpipe emissions?
a) Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx)
b) Carbon Dioxide (CO2) and Oxygen (O2)
, c) Sulfur Dioxide (SO2) and Lead (Pb)
d) Only Carbon Monoxide (CO)
13. A "scan tool" is primarily used to:
a) Measure mechanical engine compression
b) Read live data and diagnostic trouble codes from the PCM
c) Test alternator output
d) Check fuel pump pressure
14. A P0420 code (Low Catalyst Efficiency) could be caused by all of the following EXCEPT:
a) A failed catalytic converter
b) An engine misfire
c) A faulty downstream oxygen sensor
d) A faulty Mass Air Flow (MAF) sensor
15. The firing order for an engine is critical because it:
a) Determines the engine's displacement
b) Ensures the spark plugs fire in the correct sequence for smooth operation
c) Sets the timing for the oil pump
d) Controls the fuel injector pulse width
16. A leaking head gasket can cause all of the following symptoms EXCEPT:
a) Coolant and oil mixing
b) Loss of compression
c) White, sweet-smelling exhaust smoke
d) Low alternator output
17. The purpose of the Positive Crankcase Ventilation (PCV) system is to:
a) Increase engine horsepower
b) Recirculate unburned crankcase vapors back into the intake to be burned
c) Vent fuel tank vapors
d) Cool the engine oil
18. A "no-start" condition with a strong smell of fuel is often caused by:
a) A faulty ignition coil
b) A clogged fuel filter
c) An inoperative fuel pump
d) Flooded engine or leaking fuel injector(s)
19. A scope pattern showing low secondary ignition voltage is a sign of:
a) A wide spark plug gap
GUIDE – Questions And Solutions
Section 1: General Engine Knowledge & Diagnosis (20 Questions)
1. What is the primary purpose of the oil pump?
a) To filter the oil
b) To cool the oil
c) To create oil pressure and circulate oil
d) To store the oil
2. A "ticking" noise that increases with engine RPM is most likely caused by:
a) A worn rod bearing
b) A spun main bearing
c) A collapsed piston skirt
d) A faulty hydraulic lifter or low oil pressure
3. The term "engine displacement" refers to:
a) The physical size of the engine block
b) The total weight of the engine
c) The total volume swept by all the pistons
d) The distance the piston travels
4. A compression test reveals one cylinder is significantly lower than the others. A wet
compression test brings the compression back to normal. This indicates a problem with:
a) The valvetrain
b) The piston rings
c) A cracked cylinder head
d) The ignition system
5. A engine with a "knocking" noise that is deepest and loudest under load is likely suffering
from:
a) Piston slap
b) Detonation (spark knock)
c) A faulty water pump
d) A loose accessory belt
6. The Powertrain Control Module (PCM) uses input from this sensor to determine engine
load for fuel delivery and spark timing.
,a) Coolant Temperature Sensor (ECT)
b) Throttle Position Sensor (TPS)
c) Mass Air Flow (MAF) Sensor
d) Camshaft Position Sensor (CMP)
7. A P0302 diagnostic trouble code indicates a misfire in:
a) Cylinder #2
b) Bank 2
c) Cylinder #3
d) A random cylinder
8. The most likely cause of blue/gray exhaust smoke is:
a) An overly rich air/fuel mixture
b) Coolant entering the combustion chamber
c) Oil entering the combustion chamber and being burned
d) Normal condensation burn-off
9. A "lean" air/fuel mixture can cause:
a) Engine dieseling (run-on)
b) Fouled spark plugs
c) High HC and NOx emissions, and engine overheating
d) Black, sooty exhaust smoke
10. The purpose of a "vacuum test" on an engine is to check for problems related to:
a) Electrical charging system
b) Engine sealing and mechanical condition
c) Transmission fluid pressure
d) Power steering operation
11. A vehicle has a persistent overheating issue only at highway speeds. The most likely cause
is:
a) A faulty thermostat stuck closed
b) A clogged radiator
c) A faulty cooling fan clutch
d) A low coolant level
12. The catalytic converter is designed to reduce which tailpipe emissions?
a) Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx)
b) Carbon Dioxide (CO2) and Oxygen (O2)
, c) Sulfur Dioxide (SO2) and Lead (Pb)
d) Only Carbon Monoxide (CO)
13. A "scan tool" is primarily used to:
a) Measure mechanical engine compression
b) Read live data and diagnostic trouble codes from the PCM
c) Test alternator output
d) Check fuel pump pressure
14. A P0420 code (Low Catalyst Efficiency) could be caused by all of the following EXCEPT:
a) A failed catalytic converter
b) An engine misfire
c) A faulty downstream oxygen sensor
d) A faulty Mass Air Flow (MAF) sensor
15. The firing order for an engine is critical because it:
a) Determines the engine's displacement
b) Ensures the spark plugs fire in the correct sequence for smooth operation
c) Sets the timing for the oil pump
d) Controls the fuel injector pulse width
16. A leaking head gasket can cause all of the following symptoms EXCEPT:
a) Coolant and oil mixing
b) Loss of compression
c) White, sweet-smelling exhaust smoke
d) Low alternator output
17. The purpose of the Positive Crankcase Ventilation (PCV) system is to:
a) Increase engine horsepower
b) Recirculate unburned crankcase vapors back into the intake to be burned
c) Vent fuel tank vapors
d) Cool the engine oil
18. A "no-start" condition with a strong smell of fuel is often caused by:
a) A faulty ignition coil
b) A clogged fuel filter
c) An inoperative fuel pump
d) Flooded engine or leaking fuel injector(s)
19. A scope pattern showing low secondary ignition voltage is a sign of:
a) A wide spark plug gap
