Diesel Engine Troubleshooting and Maintenance, Exams of Nursing

Download Diesel Engine Troubleshooting and Maintenance and more Exams Nursing in PDF only on Docsity! ASE DIESEL ENGINES EXAM 2024 WITH 100% ACCURATE SOLUTIONS Which of the following should be done after installing a new copper injector sleeve? A. Heat it B. Dress it C. Ream the seat D. Coat it with a looking compound - Precise Answer ✔✔C. Ream the seat (This reaming ensures there will be a good clean area for the injector to seal against) A diesel engine has oil in the radiator. Which of the following would be the cause? A. Cracked piston cooling nozzle B. Cracked oil cooler C. Restricted turbocharger drain line D. Restricted exhaust gas recirculation (EGR) cooler - Precise Answer ✔✔B. Cracked oil cooler ( A cracked oil cooler will allow the oil into the cooling system; thus, oil would get in the radiator.) A diesel engine has bubbles flowing in the clear bowl on the fuel/water separator. Technician A says this is caused by a restricted fuel return line. Technician B says this is caused by leaks on the return side of the fuel system. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B - Precise Answer ✔✔D. Neither A nor B (Bubbles flowing the separator indicate an air leak on the suction side of the fuel system.) A truck has been sitting for 12 hours. Which of the following open-circuit voltages would indicate a fully charged battery? A. 11.6 volts B. 12.0 volts C. 12.6 volts D. 13.0 volts - Precise Answer ✔✔C. 12.6 (A fully charged battery should have an open-circuit voltage of 12.6 volts.) The engine oil pressure gauge fluctuates greatly. All of the following be the cause EXCEPT: A. The oil pan is overfilled B. The oil pickup tube is loose C. The wrong engine oil was installed C. Stuck open pressure differential valve D. Stuck closed pressure differential valve - Precise Answer ✔✔A. Stuck open pressure relief valve (A stuck open pressure relief valve would cause a sudden drop in engine oil pressure. Oil would be routed back to the pan or the suction side of the oil pump.) The engine compression brake is inoperative. Which of the following is the most likely cause? A. Improperly adjusted intake valves B. Misadjusted engine brake C. Failed clutch switch D. Misadjusted wastegate - Precise Answer ✔✔C. Failed clutch switch (A failed clutch switch may prevent engine brake operation.) A diesel engine equipped with hydraulic electronic unit injection (HEUI) blows excessive smoke. Technician A says the boost pressure sensor may be faulty. Technician B says the coolant temperature sensor may be faulty. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B - Precise Answer ✔✔A. A only (A failed boost pressure sensor could report incorrect boost pressure and cause the electronic control module (ECM) to over-fuel the engine, resulting in black smoke.) A diesel engine oil sample shows excessive chromium content. Which of the following would be the most likely source? A. Rod barrings B. Main bearings C. Intake valves D. Piston rings - Precise Answer ✔✔D. Piston rings (Piston rings are chrome-plated; therefore, when they wear, excessive chromium can show up in the oil sample.) When installing an injector in an engine equipped with an HEUI fuel system, which of the tools is normally used to adjust the injector? A. Dial indicator B. Torque wrench C. Height gauge D. The injector is not adjusted after installation - Precise Answer ✔✔D. The injector is not adjusted after installation ( The injector is not adjusted after installation, because oil pressure actuates the injector plunger, not the camshaft.) A charging circuit has a 2-volt drop on the positive side while under full load. Technician A says this normal. Technician B says this could be caused by a loose alternator ground. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B - Precise Answer ✔✔D. Neither A nor B (The voltage drop should be very low on this cable, even under full load. The most likely cause of this voltage drop is resistance in the circuit between the battery and alternator) Technician A says stainless steel injector sleeves need to be reamed after installation. Technician B says stainless steel injector sleeves need to be heated after installation. Who is correct? A. A only B. B only C. Both A and B D.Neither A nor B - Precise Answer ✔✔D. Neither A nor B (Copper sleeves need to be reamed after installation; stainless steel; Stainless sleeves DO NOT. It is not a requirement to apply heat to either sleeve type during this procedure.) A diesel engine has low power and overheats. Which of the following is the most likely cause? A. Restricted fuel filter B. Restricted diesel particulate filter (DPF) C. Restricted Diesel crankcase coalescing filter B. A leaking air-to-coolant aftercooler C. a leaking ECM cooler plate D. A leaking fuel cooler - Precise Answer ✔✔B. A leaking air-to-coolant aftercooler (A leaking air-to-coolant aftercooler could allow coolant into the intake manifold. As the moisture is removed, the mineral deposits will remain as a chalky dust.) Which dash switches are typically used to control engine RPM during power take- off (PTO) operation? A. Engine brake B. Cruise control C. Diagnostic D. Fan override - Precise Answer ✔✔B. Cruise control ( The cruise control switches can also be used to control the engine RPM during PTO operation.) A diesel engine has excessive wear on the rings and upper cylinder liner. Technician A says this could have been caused by a crack in the air intake piping. Technician B says this could be the result of a perforated air cleaner. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor b - Precise Answer ✔✔C. Both A and B (A crack in the air intake piping or a perforated air filter will allow dirty air to enter the engine. This dirty air will cause excessive wear of the rings and upper cylinder liner.) A diesel engine oil sample shows excessive copper content. Which of the following would be the most likely source? A. Rod bearings B. Exhaust valves C. Intake valves D. Piston rings - Precise Answer ✔✔A. Rod bearings (Bearings show up in oil samples as copper.) An electronically controlled diesel engine has run out of fuel. Which of the following must be performed before the engine will restart? A. Re-flash the ECM B. Disconnect then reconnect unswitched battery power to the ECM C. Bleed the fuel system D. Press and fold the dash-mounted diagnostic switch 10 seconds - Precise Answer ✔✔C. Bleed the fuel system (This may be accomplished on some engines by extended cranking, others may require lines to be loosened and a primer pump used) The crankcase filter requires servicing more often than normal. Which of the following could be the cause? A. Excessive crankcase pressure B. Excessive main bearing clearance C. Excessive rod bearing clearance D. Restricted DPF - Precise Answer ✔✔A. Excessive crankcase pressure (Excessive crankcase pressure can cause the filter to be saturated earlier than normal.) A diesel engine cranks slowly and the starter draws more amperage than normal; the battery voltage while cranking is 9.0 volts. Which of the following should be technician do next? A. Perform a voltage drop test on the starter cables B. Load test the battery C. Replace the starter D. Measure engine rotational torque - Precise Answer ✔✔B. Load test the battery (The battery should be load tested. if the battery cannot maintain voltage while cranking, the amperage will increase to compensate. the starter motor work is actually measured in watts. The starter motor's required watts is a relatively fixed amount. For watts to stay the same, amperage must increase as voltage drops.) Technician A says the front and back of a bearing should be lubricated prior to installation. Technician B says bearing clearance should be checked when installing new bearings. Who is correct? A. A only B. B only A. Primer the bolts B. Paint the bolts C. Replace the bolts D. Glass bead the bolts - Precise Answer ✔✔C. Replace the bolts (Head bolts that are pitted are weakened; the head bolts should be replaced.) A diesel engine has high oil consumption. Technician A says this could be caused by worn piston rings. Technician B says this could be caused by worn main bearings. Who is correct A. A only B. B only C. Both A and B D. Neither A nor b - Precise Answer ✔✔A. A only (Worn piston rings can allow oil into the combustion chamber and cause high oil consumption.) On an HEUI system, the fuel pressure regulator valve is part of which system? A. Injection control pressure system B. Fuel injector assembly C. Fuel supply system D. High-pressure oil system - Precise Answer ✔✔C. Fuel supply system (The fuel pressure regulator is a mechanically actuated valve that controls the fuel pressure in the fuel supply system.) Which of the following is the proper way to clean an air-to-air aftercooler? A. Non-sudsing detergent B. Kerosene C. Diesel fuel D. Gasoline - Precise Answer ✔✔A. Non-sudsing detergent ( Non-sudsing detergent is the safest method; it is non-flammable and non- corrosive.) A truck charges normally at higher RPMs but it is less than normal at idle. Technician A says there may be voltage drop on the negative side of the system. Technician B says there may be voltage drop on the positive side of the charging system. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B - Precise Answer ✔✔D. Neither A nor B (Most likely, the alternator is spinning slower than needed at idle, which could be caused by an incorrectly sized alternator pulley.) Which of the following is an effective tool to determine thermostat opening temperature? A. Refractometer B. Infrared pyrometer C. Hydrometer D. Injection-control pressure - Precise Answer ✔✔B. Infrared Pyrometer (An Infrared pyrometer can be used to measure the temperature around the thermostat to get a good, approximate opening temperature.) Which sensor is used by the ECM to determine current engine speed? A. Exhaust backpressure B. Accelerator Pedal position C. Camshaft position D. Injection-control pressure - Precise Answer ✔✔C. Camshaft position (The camshaft position sensor can be used by the ECM to determine RPM.) After replacing a turbocharger due to an exploded exhaust turbine wheel, what should the technician do? A. Replace the charge air cooler B. Replace the air piping C. Inspect the DPF and/ or diesel oxidation catalyst (DOC). D. Replace the turbo oil feed line. - Precise Answer ✔✔C. Inspect the DPF and/ or diesel oxidation catalyst (DOC). (The DPF and DOC will need to be inspected for damage from the exploding wheel)