ASE A1 Engine Repair Practice Test

6. A wet compression test is being performed on a four cylinder engine. The number two cylinder's compression is below specifications and remains the same after injecting oil. This result indicates:

  • A. Worn piston rings.
  • B. A faulty valve.
  • C. A hole in the piston.
  • D. Excessive carbon buildup on the piston's dome.

6.

Answer A is wrong. If compression increases after injecting oil into the chamber, the piston rings are worn. This is because the oil fills the gap caused by the worn rings increasing the cylinder's compression.

Answer B is correct. If there is no change in compression after adding oil, the cylinder has a faulty head gasket or valve.

Answer C is wrong. Answer B is correct. There would be no compression is there were a hole in the piston.

Answer D is wrong. Answer B is correct.

7. A vehicle has blue colored exhaust. Technician A says this may be caused by weak piston rings. Technician B says this may be caused by a leaking fuel injector. Who is correct?

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

7.

Answer A is correct. Oil is burning in the combustion chamber causing blue colored exhaust.

Answer B is wrong. A leaking fuel injector results in black colored exhaust from the excess fuel burning in the combustion chamber.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

8. Technician A says to remove the ridge on the engine block before removing the pistons. Technician B says a block's ridge will damage the new piston rings during installation. Who is correct?

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

8.

Answer A is wrong. Both technicians are correct.

Answer B is wrong. Both technicians are correct.

Answer C is correct. Remove the damaging ridge with a ridge reamer before removing pistons. This also prevents damage to the new piston rings when it comes time to reinstall the pistons.

Answer D is wrong. Both technicians are correct.

9. A vehicle briefly blows blue/gray smoke from the tailpipe when it's first started in the morning. The MOST likely cause of this condition is:

  • A. Worn piston rings.
  • B. Lean fuel condition.
  • C. Leaking fuel injector.
  • D. Leaking valve seal.

9.

Answer A is wrong. Worn piston rings would result in blue/gray smoke at all times, not just in the mornings.

Answer B is wrong. Both a rich and a lean fuel condition will result in excessive HC's in the emissions.

Answer C is wrong. A rich fuel condition will result in black smoke emitting from the tailpipe.

Answer D is correct. A leaking valve seal will cause oil to leak into the cylinder's chamber over time, usually overnight.

10. During a cylinder leakage test air bubbles appear in the neck of the radiator. Technician A says a faulty intake valve will cause this condition. Technician B says a crack in the engine block will cause this condition. 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. This is because the intake valve is leaking air into the intake manifold.

Answer B is correct. A crack in the blocks deck area or cylinder head allows compression to leak into the coolant jacket. This results in air bubbles appearing in the radiator neck.

Answer C is wrong. Technician B is correct.

Answer D is wrong. Technician B is correct.