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ASE test T2 55 Practice test 2 Questions
With Solutions
Which bearing wear pattern would indicate a bent crankshaft?
A. Worn lower main bearings B. Worn upper rod bearings C. Both halves of the rod bearing are worn excessively D. Both halves of the main bearings are worn excessively - โ โ D. Both halves of the main bearings are worn excessively (Excessive wear on both halves of the main bearing is an indication of a bent crankshaft) Which of the following could cause a diesel engine to derate and shut down?
A. Faulty accelerator pedal sensor B. Faulty turbo boost sensor C. Faulty low coolant level sensor D. Faulty barometric pressure sensor - โ โ C. Faulty low coolant level sensor (Many engines can be programmed to derate and then shut down due to low coolant level; therefore, a faulty low coolant level sensor could cause this condition) Which of the following is LEAST LIKELY to be found in an engine compression brake system?
A. Master Piston B. Slave Piston C. Solenoid Valve D. Brake shoes - โ โ D. Brake shoes (All the components listed can be found in an engine compression brake except brake shoes, which would be found on the chassis drum brake system) Which of the following would be the correct tool to bench test a high-pressure common-rail injector?
A. Digital multi-meter (DMM) B. Test Light C. Fused Jumper wire D. Voltmeter - โ โ A. Digital multi-meter (DMM) (A DMM set on the Ohms scale can be used to measure the resistance of the coil) Which of the following would be the most normal piston-to-cylinder wall clearance specification for a diesel engine with a four-inch bore?
A. 0.0001"-0.0003" B. 0.001"-0.003" C. 0.008"-0.015" D. 0.100"-0.300" - โ โ C. 0.008"-0.015" (This is a normal clearance) Which of the following would be used to check liner installed height?
A. Dial indicator/ Sled gage B. Inside micrometer C. Outside micrometer D. Dial caliper - โ โ A. Dial indicator/ Sled gage ( A Dial indicator, sometimes known as a sled gage, is normally used to check liner installed height) Which of the following would cause a bent valve?
A. Too much valve lash B. Too little valve lash C. Too much injector lash D. Too little injector lash - โ โ B. Too little valve lash (Too little valve lash will cause the valve to open more than specified. This could result in the valve hitting the piston, which would bend it)
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. Voltage drop on either side of the starter circuit could cause the engine to have a slow cranking speed) A diesel engine has an internal coolant leak. Which of the following could be the cause?
A. Leaking exhaust gas recirculation (EGR) cooler B. Leaking DPF C. Leaking DOC D. Cracked fuel cooler - โ โ A. Leaking exhaust gas recirculation (EGR) cooler (A leaking EGR cooler can allow coolant into the exhaust stream) A diesel engine has cracks across the face of the exhaust valves. Which of the following could cause this?
A. Using the wrong oil B. Using the wrong fuel C. Too little exhaust valve lash D. Too little intake valve lash - โ โ C. Too little exhaust valve lash (Exhaust valves cool while in the seat. Too little lash would result in too little time in the seat, overheating the exhaust valve. An overheated valve can crack across the valve face)
A diesel engine has low oil pressure at high RPM, but oil pressure is normal at lower RPM. Which of the following could be the cause?
A. Plugged pickup screen B. Dirty oil filter C. Plugged oil by-pass valve
D. Restricted oil cooler - โ โ A. Plugged pickup screen (A plugged pickup screen may let sufficient oil to pass at a lower RPM. When the engine RPM increases, the increased flow demand may cause the pump to cavitate and pressure to be low) A diesel engine has lower power. Technician A says the EGR pressure-differential sensor tubes may be clogged. Technician B says the fuel cooler may be restricted. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. Restricted EGR pressure- differential sensor tubes can cause the ECM to over-EGR the engine, which will reduce horsepower. A restricted fuel cooler can cause overheated fuel, which will reduce horsepower A diesel engine in a new truck has blown a head gasket three times int he last 2,000 miles. Which fo the following could be the cause?
A. Incorrect tire size B. Incorrect transmission ratios C. Incorrect differential ratios D. Incorrect fuel trim settings in the ECM - โ โ D. Incorrect fuel trim settings in the ECM (An ECM with incorrect programming could cause the engine to produce excessive cylinder pressure and result in head gasket failure) A diesel engine is using too much oil. All of the following could be the cause EXCEPT
A. Worn piston rings B. Worn valve guides C. Worn valve seats D. Loose oil pan fasteners - โ โ C. Worn valve seats (work valve seats can cause low compression, but will not cause oil consumption)
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ B. B only (Only Technician B is correct. A faulty accelerator pedal position sensor will not affect engine starting, but it could prevent the engine from accelerating) A driver is concerned that the engine brake will not disengage when the clutch is depressed. technician A says the clutch switch may be faulty. Technician B says the master may be faulty.
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ A. A only (Only Technician A is correct. if the engine brake does not disengage when the clutch is depressed, the clutch switch should be tested) A charging circuit has a 2-volt voltage drop on the negative side while under full load. Technician A says this is could be caused by a loose power supply wire at the alternator. 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 - โ โ B. B only (Only technician B is correct. A loose alternator ground could cause high resistance in the negative circuit and cause this amount of voltage drop) A dash-mounted temperature gauge is reading erratic. Technician A says air in the coolant can cause this. Technician B says low coolant level could cause this. Who is correct?
A. A only B. B only C. Both A and B
D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. Both air in the coolant and low coolant level can cause the coolant temperature probe not to be completely immersed in coolant. If the coolant temperature sensor probe is not totally surrounded by coolant, the sensor can give erratic information) A diesel engine cranks slowly, is hard to start, must sometimes be jump started, and sometimes fail to start. Which of the following is the most likely cause?
A. Blown ECM fuse B. Open J1939 data bus C. Excessive starter current draw D. Batteries with a high state of charge - โ โ C. Excessive starter current draw (A defective starter can draw so much amperage that battery voltage will fall below the minimum for the ECM operation and cause the engine to be hard to start) A diesel engine equipped with a common-rail fuel system 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 - โ โ A. A only (Only Technician A is correct. A failed boost pressure sensor could cause the electronic control module (ECM) to over-fuel the engine, resulting in black smoke) A diesel engine fails to reach operating temperature. Which of the following is the most likely cause?
A. Stuck open thermostat B. Stuck closed thermostat C. Slipping fan drive belt D. Slipping fan clutch - โ โ A. Stuck open thermostat ( A stuck open thermostat would tend to let the engine run cold)
B. Intake valve head protrusion C. Valve stem height D. Exhaust valve head protrusion - โ โ C. Valve stem height (Milling the cylinder head deck surface will not affect the distance the protrude farther into the combustion chamber.) An electronically controlled diesel engine has set a DTC for engine overspeeding. What must the technician do to remove the DTC that was set?
A. Re-flash the ECM B. Disconnect, then reconnect unswitched battery power to the ECM C. Contact the manufacturer for a factory password D. Press and hold the diagnostic switch in the dash for 10 seconds - โ โ C. Contact the manufacturer for a factory password (The manufacturer must be contacted, as an engine overspeeding event can be a warranty-voiding event. The manufacturer will track this data in case of future problems) An engine is being assembled, and the crankshaft end-play is greater than the specification. Which of the following could be the cause?
A. Crankshaft rod journal is out of round B. Crankshaft rod journal is tapered C. Worn crankshaft thrust surface D. Worn rear main seal surface - โ โ C. Worn crankshaft thrust surface (End-play is controlled by the clearance between the thrust surface on the crankshaft and the thrust bearing. Excessive crankshaft end-play is normally caused by excessive wear on the thrust surface of the crankshaft or a worn thrust bearing.) An overconcentration of anti-freeze in the cooling system can cause:
A. A leaking water pump B. The engine to run too cool C. Low power
D. Excessive exhaust temperature - โ โ A. A leaking water pump (An overconcentration of anti- freeze can cause silicate drop-out and water pump seals to leak) During a starter voltage drop test, voltage drop is higher than specification. Which of the following could be the cause?
A. The engine has low compression B. The battery cables have high resistance C. The flywheel ring gear teeth are worn D. The starter motor has a slipping drive - โ โ B. The battery cables have high resistance (High Resistance in the cables can cause higher-than-normal voltage, because voltage is used to push the current through the resistance) In reference to the illustration technician A says that when replacing a turbocharger assembly, the drain line should be checked for restriction. Technician B says that turbochargers are often recored by replacing the center housing as a unit and reusing the old compressor and turbine housing, who is correct?
A. A only B. B only C. Both A and B D. Neither A or B - โ โ C. Both A and B (both technicians are correct. When replacing a turbo charger, it is a good practice to inspect the oil supply and return lines to ensure proper lubricant flow at the replacement turbo charger. This can reduce the chances of the replacement turbo failing. Technician B is also correct. Turbo chargers can recored; this helps to reduce repair costs, requiring can only be performed if both the turbine and impeller housing's are in good condition). In the illustration, adjustment screw #1 is adjusted to a clearance 0.002" greater than specified. This would most likely result in:
A. An engine that is hard to start B. An engine that is low on power C. An engine that has excessive compression braking
B. While idling C. Only on a cold engine D. Only on a warm engine - โ โ A. While cranking (A starter voltage drop test is performed when the cables are under load. This means it is performed while the engine is cranking) Technician A says an EUI engine will have a computer to control the quantity of fuel delivered. Technician B says an EUI engine will have individual electronic unit injectors. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both technicians are correct. The injector is controlled by the ECM. An EUI engine has an electronically controlled unit injector for each cylinder) Technician A says oil entering the diesel particulate filter (DPF) can damage it. Technician B says oil entering the diesel oxidation convertor (DOC) can cause it to overheat. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. Oil entering the DPF and DOC can cause them to overheat) Technician A says some fan clutches found on heavy-duty highway trucks are air-applied. Technician B says some fan clutches found on heavy-duty highway trucks are air-released. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. Heavy-duty fan clutches can be air-applied or air-realeased)
Technician A says the coolant temperature sensor will normally have two or three wires in its electrical connection. Technician B says the fuel temperature sensor will normally have two or three wires in its electrical connection. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. The electrical connectors for both the coolant temperature sensor and the fuel temperature sensor typically have two or three wires.) The camshaft on a diesel engine has too much end-play. Which of the following could be the result?
A. Damaged crankshaft position sensor B. Damaged camshaft position sensor C. Damaged injector tips D. Damaged Piston cooling nozzles - โ โ B. Damaged camshaft position sensor (Excessive movement of the camshaft can allow the camshaft to contact the camshaft position sensor) The DPF pressure sensor has set a code for a restricted catalyst. Technician A says a failed turbocharger can cause the condition. Technician B says a failed injector can cause this condition. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ C. Both A and B (Both Technicians are correct. When unmetered fuel or oil is allowed to enter the DPF (caused by a failed turbocharger or a failed injector), the chances of a melted or plugged DPF is high) The ECM mounting plate has fuel passing through it. Which of the following is true of this design?
There are air bubbles in the sight glass of the fuel/water separator. Which of the following could be the cause? Technician A says there could be a hole in the suction-side hose of the fuel system. Technician B says there could be a hole in the pressure-side hose of the fuel system. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B - โ โ A. A only (Only Technician A is correct. A leak in the fuel suction system could show up as bubbles in the fuel/water separator) There are bubbles in the cooling system. Which of the following could be the cause?
A. cracked jacket water aftercooler B. Cracked oil cooler C. Cracked piston skirt D. Cracked fuel cooler - โ โ A. cracked jacket water aftercooler (The jacket water aftercooler uses engine coolant to cool the turbo charged air.) A crack could allow turbocharged air to enter the coding system) When installing an injector in an engine equipped with a high-pressure common-rail fuel system, which of the following tools is normally used to adjust the injector?
A. Dial injector B. Torque wrench C. Height gauge D. The injector is not adjusted after installation - โ โ D. The injector is no adjusted after installation (The injector is not adjusted after installation, because high pressure is supplied to the injector, and the injector is opened electronically) When replacing the ECM, which of the following should be done first?
A. Remove the positive battery cable at the battery B. Remove the negative battery cable at the battery C. Disconnect the positive battery cable at the magnetic switch D. Replace the injectors as they are matched to the ECM - โ โ B. Remove the negative battery cable at the battery (The negative cable should be removed first to precent arcing.)
