ASE A1 Engine Repair Practice Test

41. 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.

41.

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.

42. A metallic knocking sound is heard behind an engine's harmonic balancer. An oil pressure test indicates oil pressure is below specifications. Technician A says the engine's main bearing inserts should be inspected for wear. Technician B says a worn thin crankshaft thrust bearing will cause this condition. Who is correct?

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

42.

Answer A is wrong. Both technicians are correct. Front main bearings can wear from too much belt tension. Engine bearings are designed to wear before damage to the crankshaft or block occurs.

Answer B is wrong. Worn thrust bearings will result in excessive crankshaft end-play. The oil pan should be removed and the parts inspected for wear. If brass is present in the bottom of the oil pan suspect worn engine bearings.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

43. 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

43.

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.

44. 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.

44.

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.

45. 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

45.

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.