ASE A8 Engine Performance Practice Test

1. Technician A says to complete the vehicle manufacturer's recommended drive cycle after replacing the engine control module. Technician B says completing a drive cycle includes driving the vehicle at a certain speed for a specific time. Who is correct?

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


Answer A is wrong. Disconnecting power from the engine control module renders OBDII monitors not ready to monitor vehicle emissions.

Answer B is wrong. Complete a drive cycle to set OBDII monitors. It includes steps like accelerating, cruising, and decelerating the vehicle at certain speeds for a fixed time.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

2. A vehicle has a momentary hesitation only during acceleration. The MOST likely cause of this condition is:

  • A. A faulty exhaust gas recirculating valve. (EGR)
  • B. A faulty oxygen sensor. (O2 Sensor)
  • C. A faulty positive crankcase ventilation valve. (PCV)
  • D. A faulty throttle position sensor. (TPI)


Answer A is wrong. This actuator would not likely cause this condition.

Answer B is wrong. This sensor would not likely cause this condition.

Answer C is wrong. This valve would not likely cause this condition.

Answer D is correct. A faulty TP sensor can cause hesitation during acceleration.

3. A four-cylinder EFI engine has an engine code indicating insufficient EGR flow. The EGR solenoid has been tested and found to be faulty. This causes:

  • A. High CO emissions.
  • B. High HC emissions.
  • C. High CO2 emissions.
  • D. High NOx emissions.


Answer A is wrong. (CO) Carbon monoxide is the toxic compound that forms with partially burned fuel from rich fuel mixtures.

Answer B is wrong. (HC) Hydrocarbons are unburned fuel resulting from rich fuel mixtures and misfires.

Answer C is wrong. (CO2) Carbon dioxide is actually desired over carbon monoxide, though it is considered a greenhouse gas.

Answer D is correct. NOx stands for oxides of nitrogen. These gases are formed with high cylinder temperatures. They are considered pollutants. A stuck open EGR valve will result in excessive exhaust gas flow into the intake manifold. This results in engine stumble at idle. A stuck closed EGR valve results in excessive NOx emissions.

4. A vehicle has suffered a sudden drop in fuel economy. The variable valve solenoid is commanded on, and there is no change in engine operation. Technician A says to inspect the variable valve system’s oil control valve. Technician B says contaminated engine oil can result in this condition. Who is correct?

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


Answer A is wrong. VVT or variable valve timing adjusts valve timing to meet operating conditions. The easiest and most common method advances and retards valve timing, but does not alter valve lift. Newer more efficient systems also alter valve lift.

Answer B is wrong. Regular maintenance and oil changes are vital. The actuators and phasers in these systems are operated by oil pressure.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

Diagram of automotive PCM engine control system.

5. The engine in the diagram above:

  • A. Has an HEI distributor.
  • B. Has a waste spark ignition system.
  • C. Has sequential fuel injection.
  • D. Has multiport fuel injection.


Answer A is wrong. The engine has sequential fuel injection; each cylinder gets an injector offering more control and precise timing.

Answer B is wrong. The engine has (COP) coil on plug ignition; each cylinder has an ignition coil.

Answer C is correct. Sequential fuel injection systems fire each injector individually.

Answer D is wrong. This system is different from a multiport injection system, where the PCM fires more than one injector simultaneously.