ASE A1 Engine Repair Practice Test

31. A vehicle has heavy white smoke emitting from its tailpipe at all engine speeds. The cause of this problem is:

  • A. Worn piston rings.
  • B. A leaking head gasket.
  • C. Worn valve seals.
  • D. A leaking fuel injector.

31.

Answer A is wrong. Worn piston rings result in blow-by and oil burning in the combustion chamber producing blue/gray exhaust.

Answer B is correct. A leaking head gasket results in a coolant leak from the jacket into the cylinder producing white/gray exhaust.

Answer C is wrong. Leaking valve seals result in oil entering the combustion chamber, especially overnight or after sitting a while. At start up the engine will produce blue/gray exhaust from this oil burning in the combustion chamber. This symptom may go away after the engine runs a while, but return again after the vehicle sits.

Answer D is wrong. A leaking fuel injector results in a rich condition producing excessive hydrocarbons and black exhaust.

32. A vacuum gauge is connected to a port on the intake manifold of an engine with poor performance. The needle on the gauge fluctuates between 15 "hg and 20 "hg vacuum at idle. This vacuum gauge reading indicates:

  • A. A normal condition.
  • B. Late ignition or valve timing.
  • C. A sticking valve or misfire.
  • D. A restricted exhaust system.

32.

Answer A is wrong. A gauge that reads steady (17 "hg - 22 "hg) indicates a normal running engine. Vacuum is measured inches of mercury vacuum or "hg.

Answer B is wrong. A gauge that reads a steady low (15 "hg - 20 "hg) indicates late valve or ignition timing, leaking manifold gasket, low compression, leaking carburetor, or a stuck throttle valve.

Answer C is correct. A gauge that fluctuates between (15 "hg and 20 "hg) indicates a stuck valve or engine misfire.

Answer D is wrong. A gauge needle that drops slowly at idle indicates a clogged or blocked exhaust.

33. Technician A says an engine's main bearing insert has a hole that must align with the matching bores oil supply hole. Technician B says that crankshaft bore alignment can be checked with a feeler gauge and a straightedge. Who is correct?

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

33.

Answer A is wrong. Both Technicians are correct.

Answer B is wrong. Both Technicians are correct.

Answer C is correct. Always make sure the two holes and all bores are in alignment when replacing the crankshaft bearing inserts.

Answer D is wrong. Both Technicians are correct.

34. A cylinder power balance test is being performed on a vehicle with sequential fuel injection. Two adjacent cylinders are under performing. Technician A says this could be due to a faulty head gasket. Technician B says this could be due to leaking secondary insulation. Who is correct?

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

34.

Answer A is wrong. Both technicians are correct. A faulty or blown head gasket will leak compression into adjacent cylinders.

Answer B is wrong. Both technicians are correct.

Answer C is correct. Both restricted fuel injectors and leaking secondary wires will reduce the cylinder's contribution.

Answer D is wrong. Both technicians are correct.

35. Two technicians are discussing hydraulic lifter preload. Technician A says excessive preload will cause high manifold vacuum. Technician B says insufficient preload will cause excessive valve train noise. Who is correct?

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

35.

Answer A is wrong. Excessive hydraulic lifter preloads will cause low manifold vacuum.

Answer B is correct. Insufficient lifter preloads will cause valve train noise.

Answer C is wrong. Technician B is correct.

Answer D is wrong. Technician B is correct.