ASE A1 Engine Repair Practice Test
41. A broken timing belt on an interference engine can result in damage to:
- A. The intake valves.
- B. The exhaust valves.
- C. The pistons.
- D. All of the above.
Answer A is wrong. Interference engines offer more performance than freewheeling engines, because of their high compression small-displacement design.
Answer B is wrong. If the timing belt or chain breaks, the valves and the pistons collide, causing severe engine damage.
Answer C is correct. The valves can strike the pistons when an interference engine is out of timing. Freewheeling non-interference engines have enough clearance between the valves and the dome of the pistons to prevent this catastrophic event.
Answer D is wrong. A broken timing belt on an interference engine can result in damage to the pistons, intake, and exhaust valves.
42. During a cylinder leakage test, the technician hears a hissing sound at the tailpipe. This sound is caused by:
- A. A leaking head gasket.
- B. A burned exhaust valve.
- C. Worn piston rings.
- D. A bent intake valve.
Answer A is wrong. Performed a cylinder leakage or leak-down test after a cylinder balance, and a cylinder compression test has verified the problem cylinder. It indicates the percentage of leakage and pinpoints the part causing the leak.
Answer B is wrong. Listen for air escaping through the tailpipe, indicating a problem with the exhaust valve.
Answer C is wrong. Air escaping through the oil fill cap or dipstick indicates worn piston rings.
Answer D is correct. Listen for air hissing through the throttle body or carburetor. This sound indicates a problem with the intake valve. It’s allowing compression to seep past the valve and its seat.
43. A faulty ECT sensor results in all of the following EXCEPT:
- A. A rich air-fuel ratio.
- B. An inoperative torque converter clutch.
- C. Blue-gray exhaust emitting from the tailpipe.
- D. An inoperative engine cooling fan.
Answer A is wrong. Symptoms of a faulty (ECT) engine coolant temperature sensor include a rich air-fuel ratio and poor fuel mileage. They're (NTC) or negative temperature coefficient thermistors. As the coolant's temperature increases, the sensor's resistance decreases.
Answer B is wrong. The ECM uses this signal to make adjustments to engine cooling fans, fuel injectors, and transmission (TCC) torque converter clutch actuator.
Answer C is correct. The ECT's signal informs the ECM of the engine's operating temperature. A false signal may result in a rich air-fuel ratio and black-colored exhaust at the tailpipe.
Answer D is wrong. The ECM uses this signal to make adjustments to engine cooling fans and the fuel injectors.
44. A longitudinal engine makes a loud, whirring noise that gets louder when the engine is revved. Which of the following is causing this condition?
- A. A faulty viscous fan clutch.
- B. A worn accessory belt.
- C. A weak electric cooling fan motor.
- D. A cracked fan blade.
Answer A is correct. A seized viscous fan clutch makes a whirring noise because the clutch is locked and not slipping, spinning the fan blades at engine speed at all times.
Answer B is wrong. A worn accessory belt squeals. Visually inspect the belt at a pulley for cracks and excessively worn edges.
Answer C is wrong. A weak electric fan motor results in engine overheating.
Answer D is wrong. Bent, cracked, or missing blades cause an imbalance and a vibration. This problem can result in damage to the water pump bearings and seals.
45. An vehicle has black-colored exhaust and a lack of power when accelerating. Technician A says a rich air-fuel ratio may have clogged the catalytic converter. Technician B says to use a back pressure tester to test for a restriction in the exhaust system. Who is correct?
- A. Technician A
- B. Technician B
- C. Both A and B
- D. Neither A or B
Answer A is wrong. When a vehicle is running rich, the catalytic converter is working harder and running hotter than intended. This heat can damage the substrate and cause it to melt and degrade. The melted substrate results in excessive backpressure.
Answer B is wrong. Perform a backpressure test to confirm a clogged catalytic converter. Backpressure testers test for restrictions in the exhaust flow. Remove the upstream oxygen sensor to install the tester.
Answer C is correct. Both technicians are correct; a melted substrate results in excessive backpressure.
Answer D is wrong. A clogged catalytic converter causes a restriction that results in a noticeable drop in power during acceleration.