ASE A8 Engine Performance Practice Test

41. Technician A says a turbocharger boost pressure sensor provides the intake manifold's boost pressure to the PCM. Technician B says a leaking wastegate diaphragm will affect the turbocharger's boost pressure. Who is correct?

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

41.

Answer A is wrong. Both technicians are correct. The boost pressure sensor provides the intake manifold's boost pressure to the PCM and is typically located on the charger.

Answer B is wrong. A spring keeps this gate normally closed at idle. As pressure increases, the valve opens the wastegate allowing exhaust pressure to bypass the turbine wheel.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

Diagram of automotive PCM engine control system.

42. The vehicle in the diagram above contains:

  • A. A (COP) coil on plug ignition system.
  • B. A wastespark ignition system.
  • C. A sequential port electronic fuel injection system.
  • D. A (TBI) throttle body fuel injection system.

42.

Answer A is wrong. Answer B is correct.

Answer B is correct. This is a diagram of a wastespark ignition system.

Answer C is wrong. This is a multiport fuel injection system. The PCM actuates two injectors at once

Answer D is wrong. Answer B is correct.

43. An engine with a viscous fan clutch is overheating while the engine idles. Technician A says this type of fan clutch should be visually inspected for fluid leakage. Technician B says the system's relay may be sticking closed. Who is correct?

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

43.

Answer A is correct. This type of fan operates with a silicon type fluid. A loss of fluid limits the operation of the viscous fan clutch.

Answer B is wrong. Relays are used in electric radiator fan circuits.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

44. A fuel pressure test performed at the fuel rail of a SFI sequential fuel injection engine indicates lower than specified fuel pressure. All of the following cause low fuel pressure EXCEPT:

  • A. A poor ground in the pump circuit.
  • B. A kink in the fuel return line.
  • C. A restricted fuel filter.
  • D. A faulty fuel pump.

44.

Answer A is wrong. A poor ground or power condition would result in low fuel pressure.

Answer B is correct. This is an EXCEPT type question. A restricted fuel return line would increase fuel pressure at the rail.

Answer C is wrong. A restricted or clogged fuel filter would result in low fuel pressure at the rail.

Answer D is wrong. A faulty or defective fuel pump would result in low fuel pressure at the rail. A faulty fuel pump is the most common cause of low fuel pressure.

Automotive engine sensor.

45. The sensor illustrated above is a:

  • A. Thermistor
  • B. Permanent Magnet
  • C. Potentiometer
  • D. Pressure Switch
Automotive engine sensor.

45.

Answer A is wrong. Thermistors measure temperature.

Answer B is correct. The sensor above is a permanent magnet sensor. Crankshaft and camshaft position sensors are used by engine manufacturers as position sensors.

Answer C is wrong. The Throttle Position (TP) sensor is located on the throttle body of a fuel injected engine.

Answer D is wrong. An oil pressure switch sends a signal directly to the driver’s instrument panel or to the engine control module.