Fuel System Test

1. Which of the following is NOT an objective of a typical fuel subsystem?

• A) Store fuel in a tank until required.

• B) Remove moisture from the fuel.

• C) Filter fuel to remove abrasive particulates.

• D) Generate electrical power for the vehicle.

• E) Monitor fuel tank level, fuel pressure, fuel temperature, and alert a water-in-fuel condition.

2. Which of the following correctly lists the three circuits into which the fuel system is divided?

• A) High-pressure circuit, medium-pressure circuit, low-pressure circuit.

• B) High-pressure circuit, internal low-pressure circuit, chassis low-pressure circuit.

• C) Injection circuit, supply circuit, return circuit.

• D) Fuel storage circuit, fuel delivery circuit, fuel monitoring circuit.

• E) High-pressure circuit, internal medium-pressure circuit, chassis low-pressure circuit.

3. What is the purpose of the excess fuel pumped through the fuel system, beyond the amount required to fuel the engine?

• A) To increase fuel efficiency.

• B) To lubricate and cool high-pressure injection components and cool electronic components.

• C) To reduce emissions.

• D) To prevent fuel leakage.

• E) To improve engine performance.

4. What is the primary function of a breather filter in a fuel system?

• A) To increase fuel efficiency.

• B) To prevent dirt, dust, and other contaminants from entering the fuel tank.

• C) To monitor fuel levels in the tank.

• D) To cool the fuel before it reaches the engine.

• E) To improve the fuel injection process.

5. In a typical two-stage filtering fuel subsystem, which of the following statements correctly describes the roles of primary and secondary filters?

• A) Primary filters are the second filter and are more restrictive due to lower pressure; secondary filters are the first filter and entrap larger particles.

• B) Primary filters are the first filter and entrap smaller particles; secondary filters are the second filter and are less restrictive.

• C) Primary filters are the first filter and entrap particles larger than 10 to 30 micrometers under lower than atmospheric pressure; secondary filters are the second filter, charged by the transfer pump and more restrictive due to higher pressure.

• D) Primary filters and secondary filters have the same role but differ in their placement within the system.

• E) Primary filters are under higher pressure and entrap larger particles; secondary filters are under lower pressure and entrap smaller particles.

6. In which form does water appear in diesel fuel as large globules that collect in puddles at the bottom of the fuel tank?

• A) Free state.

• B) Emulsified.

• C) Semi-absorbed.

• D) Dissolved.

• E) Vaporized.

7. What is the primary function of a hand primer pump in some fuel subsystems?

• A) To increase fuel pressure.

• B) To filter the fuel.

• C) To eliminate air from the fuel subsystem.

• D) To cool the fuel.

• E) To measure fuel level in the tank.

8. Which of the following statements correctly describes the SAA6D170 - HPI fuel system developed by Cummins & Komatsu?

• A) It uses a complex design with fixed injection timing and similar injection pressures to other Cummins or Komatsu fuel systems.

• B) It features a simple and efficient design, offering unlimited variable injection timing, with injection pressures different from other Cummins or Komatsu fuel systems.

• C) It is an older fuel technology with limited variable injection timing and similar injection pressures to other Cummins or Komatsu fuel systems.

• D) It eliminates the need for variable injection timing and uses a simple design with lower injection pressures than other Cummins or Komatsu fuel systems.

• E) It uses a simple design with fixed injection timing and higher injection pressures than other Cummins or Komatsu fuel systems.

9. Which of the following components is NOT part of the Hydro-mechanical system diagram of the SAA6D170 - HPI fuel system?

• A) Fuel filter head and fuel filter element.

• B) Fuel pump.

• C) Fuel control valve assembly.

• D) Turbocharger.

• E) Fuel cooler.

 

10. Which of the following is a probable cause and remedial action for an engine that starts normally but misfires?

• A) No fuel to injectors - Flush fuel system.

• B) Contaminated fuel - Check for restrictions or air leaks in fuel system.

• C) Air in fuel - Bleed system, check for air leaks.

• D) Glow-plug failure - Replace glow-plug control module.

• E) Insufficient fuel supply - Disconnect fuel return line to verify flow and remove obstruction.