Chapter 2 DIAGNOSIS AND SERVICE OF ENGINE SYSTEM

Low oil pressure is observed in an engine. Which is the MOST probable cause?

• Overfilled engine oil

• Clogged oil filter

• New piston rings installed

• Clean oil pan

Answer explanation

A clogged oil filter restricts oil flow, lowering oil pressure.

What is one consequence of low oil pressure in an engine lubrication system?

• Reduced engine speed

• Increased engine wear

• Improved engine seal
  

• Enhanced oil viscosity

What serious issue can occur if the cooling system or any part of it fails?

• Reduced fuel efficiency

• Engine overheating

• Improved engine performance

• Increased oil pressure

What does the process of "bleeding the cooling system" involve?

• Locating and repairing radiator leaks

• Testing the drive belt

• Removing air from the cooling system

• Cleaning the cooling system

What is the purpose of chemical cleaning in a fuel system maintenance?

• To increase fuel efficiency

• To remove deposits settled in the fuel system

• To replace worn components

• To adjust fuel injectors

Why is it important to replace components like the fuel pump, fuel filter, or fuel injectors during fuel system maintenance?

• To increase exhaust emissions

• To enhance engine noise

• To prevent deposits in the fuel system

• To improve fuel efficiency

What is a potential problem associated with a malfunctioning mechanical fuel pump?

• Excessive fuel consumption

• Lack of engine power

• Insufficient fuel delivery

• Slow engine warm-up

What could be a sign of a defective accelerator pump system during a quick inspection of the carburetor?

• Slow engine warm-up

• Lack of engine power during acceleration

• Dripping oil from the main nozzle

• No discharge of fuel into the primary barrel

What role does the Engine Control Unit (ECU) play in an EFI vehicle?

• Controls the injection of fuel and spark timing

• Monitors tire pressure

• Regulates air conditioning

• Manages the radio system

How are ECU fault codes typically retrieved from a vehicle?

• By checking the oil level

• Using a diagnostic scan tool

• Observing the exhaust color

• Disconnecting the battery

Answer explanation

Scan tools interface with OBD-II to read ECU-stored codes.