ASE A1 Engine Repair Practice Test

6. A spark plug has a square electrode and the tip is light gray colored. Which of the following is correct about this spark plug reading?

  • A. The piston rings are worn.
  • B. The fuel injector is leaking.
  • C. The engine has a bad valve.
  • D. This reading shows normal wear.

6.

Answer A is wrong. Black carbon deposits indicate an oil control problem. Sometimes the tip is wet with oil.

Answer B is wrong. Black flakey soot on the tip and electrode indicates a rich fuel condition. If a spark plug is wet it could be oil, fuel or coolant. A dripping fuel injector will result in a wet spark plug tip that smells like raw fuel.

Answer C is wrong. A bad valve results in black carbon deposits.

Answer D is correct. A light tan or light gray colored spark plug tip is considered normal. Today’s fuel injected engines usually turn the tip a light gray color. The center electrode should be square, not rounded; this is because spark readily jumps off a square edge.

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7. While removing the spark plugs from an engine, it is noticed that one spark plug's ceramic insulator is shorter than the others. Technician A says that the shorter spark plug has a different heat range than the other plugs. Technician B says a cold spark plug with too low of a heat range for that engine may foul prematurely. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

7.

Answer A is wrong. Spark plugs have different heat ranges and thread lengths.

Answer B is wrong. A spark plug must be hot enough to prevent fouling, yet cool enough to avoid pre-ignition or detonation.

Answer C is correct. A hot spark plug self cleans better than a cold plug, but a cold plug is better at preventing pre-ignition. Pre-ignition occurs when the air/fuel charge has burned too soon, and detonation occurs when the air/fuel charge burns too fast. Manufacturers' spend a great deal of time choosing the right spark plug for their engine.

Answer D is wrong. Both technicians are correct.

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8. A light duty truck with a five-speed manual transmission has a rattling noise at the back of the engine that increases with engine speed. Technician A says the flywheel bolts may be loose. Technician B says to torque flywheel bolts in a crisscross pattern according to the manufacturer's specifications. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

8.

Answer A is wrong. Manual transmissions have flywheels that absorb engine pulses transferred through the crankshaft.

Answer B is wrong. Automatic transmissions have flexplates that contain the starter ring around the outside of their circumference. The mass of the torque converter acts like a flywheel, smoothing out engine pulses.

Answer C is correct. Loose flywheel or flexplate bolts make a rattling sound heard toward the rear of the engine where it's joined to the transmission's bellhousing.

Answer D is wrong. Answer C is correct.

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9. The oil pressure warning light stays illuminated whenever the engine is running. The oil pressure is within specifications. Technician A says the oil pressure switch may be faulty. Technician B says to test the oil pressure switch with an ohmmeter. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

9.

Answer A is wrong. Use a digital multimeter set to Ohms.

Answer B is wrong. They can be tested for operation with the engine not running and then with the engine running.

Answer C is correct. They are often normally closed switches; this is why the oil pressure warning light illuminates when the ignition is first turned on and goes out after the engine starts and oil pressure rises.

Answer D is wrong. Both technicians are correct.

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10. During a cylinder leakage test, a hissing sound is heard coming from the tailpipe. Technician A says a faulty intake valve will cause this test result. Technician B says a leaking head gasket will cause this sound at the tailpipe. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

10.

Answer A is wrong. A leaking intake valve will result in a hissing sound from the throttle body. It can be heard by removing the air tube and opening the throttle plate. The intake valve is leaking air into the intake manifold.

Answer B is wrong. A faulty head gasket or a crack in the blocks deck area or cylinder head allows compression to leak into the coolant jacket. It results in air bubbles appearing in the radiator neck.

Answer C is wrong. Neither technician is correct.

Answer D is correct. A hissing sound from the tailpipe indicates a leaking exhaust valve or seat. The exhaust valve leads to the exhaust manifold /tailpipe.

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