ASE Diesel Engines test T2 practice test 1 Questions and Answers well Explained Latest 2024/2025 Update 100% Correct.

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 - A. Rod bearings (Bearings show up in oil samples as copper.) A diesel engine suddenly loses oil pressure at idle. Which of the following could be the cause? A. Stuck open pressure relief valve B. Stuck closed pressure relief valve C. Stuck open pressure differential valve D. Stuck closed pressure differential valve - A. Stuck open pressure relief valve 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 - 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'srequired watts is a relatively fixed amount. For watts to stay the same, amperage must increase as voltage drops.) A diesel engine equipped with a pump-line nozzle electronic (PLN-E) fuel system has a single-cylinder misfire on cylinder #3. Which of the following could be the cause? A. Restricted fuel filter B. Restricted air filter C. Cracked delivery valve D. Cracked vibration damper - C. Cracked delivery valve (A cracked delivery valve can cause an injector nozzle to dribble, causing a single-cylinder misfire) 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 - 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 equipped with the HEUI fuel system has a poor fuel economy concern. Technician A says a fan clutch stuck on could cause this. Technician B says a failed clutch brake could cause this. Who is correct? A. A only B. B only C. Both A and B D. Neither A nor B - A. A only(A fan clutch that has the fan engaged continually would work the engine harder and cause a decrease in fuel economy.) 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. Restricted radiator D. Restricted charge air cooler - A. Stuck open thermostat (A stuck open thermostat would tend to let the engine run cold.)