ASE Diesel Practice Test Questions and Answers

ASE Diesel Practice Test Questions and Answers When a diesel engine is operated under a load, coolant continually comes out of the radiator overflow and there are bubbles in the radiator. Which of these is the most likely cause? (A) Too much coolant in the cooling system (B) A clogged radiator (C) A stuck-open thermostat (D) Compression leakage into the cooling system - Answer-D A diesel engine has excessive black smoke when started in the morning. Which of these could be the cause? (A) A bad fuel injection nozzle (B) A restricted fuel filter (C) A blocked fuel tank vent (D) A leaking fuel return line - Answer-A Which of these can cause a no-start condition on a HEUI engine? (A) High fuel pressure EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024 Page 2/13 (B) Low injection control pressure (C) High boost pressure (D) Low boost pressure - Answer-B A diesel engine is hard to start, but runs good after it has been primed and run for a few minutes. The most likely cause is a: (A) leaking injector line. (B) leaking fuel return line. (C) plugged fuel tank vent. (D) bad transfer pump check valve. - Answer-D A diesel engine with wet liners has been running too hot, and there is coolant in the crankcase. The most likely cause is: (A) a cracked block. (B) cracked liners. (C) leaking liner seals. (D) a leaking injector seal. - Answer-C Diesel engine cylinder liner protrusion (height) can be adjusted by selecting the correct size: (A) cylinder liner. (B) head gasket. (C) liner shim. EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024 Page 3/13 (D) fire ring. - Answer-C An electronically-controlled diesel engine will not start. Any of these could be the cause EXCEPT a failed: (A) camshaft position sensor. (B) engine control module (ECM). (C) ECM ground circuit. (D) throttle position sensor (TPS). - Answer-D The cause of a logged fault code in an electronic diesel engine has just been repaired. Technician A says that the codes should be cleared before releasing the vehicle. Technician B says that the customer's password should be reset before releasing the vehicle. Who is right? (A) A only (C) Both A and B (B) B only (D) Neither A nor B - Answer-A A diesel engine has low power and low turbocharger boost pressure is found. Technician A says that a leaking exhaust manifold could be the cause. Technician B says that a plugged turbocharger oil return line could be the cause. Who is right? (A) A only (B) B only EMILLECT 2024/2025 ACADEMIC YEAR ©2024 EMILLECT. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER, 2024 Page 4/13 (C) Both A and B (D) Neither A nor B - Answer-A The parking brakes fail to apply on a truck with air brakes. Technician A says that low air pressure in the spring brake chamber could be the cause. Technician B says that a ruptured spring brake diaphragm could be the cause. Who is right? (A) A only (B) B only (C) Both A and B (D) Neither A nor B - Answer-D A truck equipped with air brakes has an uneven braking problem. Which of these could be the cause? (A) A binding treadle (foot) valve (B) Low brake line