ASE S2 - School Bus Diesel Engines Engine Practice Questions

What process in a diesel engine compresses the air before fuel injection?

• AA. Ignition
• BB. Combustion
• CC. Exhaust
• DD. Compression

Why is it important to maintain proper coolant levels in a diesel engine?

• AA. To save weight
• BB. To improve fuel efficiency
• CC. To prevent overheating
• DD. To reduce emissions

What should you check if the diesel engine in the school bus is overheating?

• AA. Coolant level
• BB. Tire pressure
• CC. Fuel injection system
• DD. Oil level

What is a common symptom of a failing fuel pump in a diesel engine?

• AA. Increased noise
• BB. Low oil pressure
• CC. Hard starting
• DD. Engine overheating

What could cause excessive black smoke from a diesel engine?

• AA. Worn out spark plugs
• BB. Low oil level
• CC. Lean fuel mixture
• DD. Rich fuel mixture

If a diesel engine is idling rough, what component is likely to be faulty?

• AA. Air filter
• BB. Fuel filter
• CC. Cylinder head
• DD. Exhaust system

What action should be taken before performing maintenance on a school bus diesel engine?

• AA. Turn on ignition
• BB. Verify tire pressure
• CC. Disconnect the battery
• DD. Check the oil level