ASE T2 Domain 6: Fuel System Diagnosis and Repair Welcome to your ASE T2 Domain 6: Fuel System Diagnosis and Repair 1. ASE T2: Fuel System Diagnosis and Repair A diesel engine with common-rail fuel injection is experiencing higher than normal fuel temperatures. What could be the cause of this condition? A. Faulty fuel injectors B. Insufficient fuel line insulation C. Restricted fuel return line D. Inoperative fuel cooler None 2. ASE T2: Fuel System Diagnosis and Repair When diagnosing a diesel engine that is difficult to start, a technician should check the fuel system for all of the following EXCEPT: A. Air in the fuel system B. Incorrect fuel timing C. High fuel pressure D. Clogged fuel filters None 3. ASE T2: Fuel System Diagnosis and Repair If a diesel fuel injector is producing a chuffing sound at idle, what is the most probable cause? A. Nozzle needle sticking B. Excessive back leakage C. Incorrect injector opening pressure D. Damaged injector body None 4. ASE T2: Fuel System Diagnosis and Repair After replacing the fuel filters on a diesel engine, the engine runs for a short period and then stalls. The primary cause could be: A. The fuel pump is damaged. B. Air is trapped in the fuel system. C. There is a restriction in the fuel supply line. D. The new fuel filters are defective. None 5. ASE T2: Fuel System Diagnosis and Repair A diesel engine is producing white smoke continuously while running. This could be due to: A. Incomplete combustion because of low cylinder temperatures. B. Excessive fuel pressure. C. A leaking exhaust system. D. Advanced fuel injection timing. None 6. ASE T2: Fuel System Diagnosis and Repair During the testing of an electronic diesel fuel injection system, it is found that one injector is not delivering fuel. The LEAST likely cause for this condition is: A. An open circuit in the injector coil. B. A seized injector plunger. C. A blown fuse for the injector circuit. D. A clogged fuel filter. None 7. ASE T2: Fuel System Diagnosis and Repair What could be the consequence of excessive return flow from diesel injectors? A. Increased fuel system pressure B. Decreased high-side fuel system pressure C. Rich air-to-fuel mixture D. Enhanced fuel atomization None 8. ASE T2: Fuel System Diagnosis and Repair A diesel engine's performance has deteriorated and it produces a knocking sound. A technician suspects incorrect fuel timing. Which of the following would be the most direct method of checking fuel timing? A. Using a scan tool to check for timing-related fault codes. B. Measuring the fuel pressure at idle and full load. C. Inspecting the camshaft and crankshaft timing marks. D. Performing a cylinder cut-out test. None 9. ASE T2: Fuel System Diagnosis and Repair A technician finds that a diesel engine is running with a slightly blue smoke and a misfire on one cylinder. After inspection, the most probable cause is determined to be: A. A leaking turbocharger seal. B. An injector with a dripping nozzle. C. Over-fueling of all cylinders. D. A defective air cleaner element. None 10. ASE T2: Fuel System Diagnosis and Repair When a diesel engine exhibits symptoms of hard starting and erratic idling after a hot soak, the fault is most likely related to: A. Vapor lock in the fuel system. B. Insufficient fuel supply. C. Air entering the fuel delivery system. D. High ambient temperatures affecting the fuel cooler. None 11. ASE T2: Fuel System Diagnosis and Repair What would be a likely cause for diesel fuel to be found in the engine oil during an oil change? A. Turbocharger seal failure. B. Defective fuel injector seal. C. Ineffective oil separator. D. Worn piston rings. None 12. ASE T2: Fuel System Diagnosis and Repair During a dynamic fuel system test, a diesel engine demonstrates a drop in rail pressure when demand increases. This symptom is most likely caused by: A. An obstructed fuel tank vent. B. A failing high-pressure fuel pump. C. Inoperative fuel injectors. D. A restriction in the air intake system. None 13. ASE T2: Fuel System Diagnosis and Repair A technician is diagnosing a common rail diesel engine that exhibits excessive noise and vibration. The most likely cause of this condition is: A. Worn engine mounts B. Air in the fuel system C. Faulty EGR valve D. Timing gear backlash None 14. ASE T2: Fuel System Diagnosis and Repair While performing a cylinder balance test on a diesel engine, one cylinder shows no change in engine speed or sound when cut out. Before disassembling the engine, the technician should FIRST: A. Replace the associated fuel injector. B. Perform a compression test on the affected cylinder. C. Check the injector wiring harness for that cylinder. D. Inspect the intake system for obstructions. None 15. ASE T2: Fuel System Diagnosis and Repair What condition is indicated by a diesel engine's fuel filter housing being empty of fuel after sitting overnight? A. Fuel siphoning back into the tank B. A bad check valve in the fuel pump C. A leaky fuel pressure regulator D. Clogged fuel return line None 1 out of 15 Time is Up! Time's up
