AET239 (1-11) Quizzes (2023/2024) Already Passed

AET239 (1-11) Quizzes (2023/2024) Already Passed Technician A says when attempting to locate an engine performance problem, you should observe the engine's exhaust smoke. Technician B says when attempting to locate an engine performance problem, you should listen for any abnormal engine noises. Who is right? Both A & B An engine is brought into the shop with a misfire problem. Technician A says to use a scan tool to find out which cylinders are misfiring. Technician B says to suspect the spark plug ignition coil, and the high voltage conductor before checking cylinder compression. Who is right? Both A & B All of the following may cause an engine to surge except: Starter Solenoid Problem Define the term misfiring. A performance problem resulting from one or more cylinders failing to fire normally or at all. Technician A says engine hesitation is normally caused by a temporarily rich air-fuel mixture. Technician B says engine hesitation is usually caused by a temporarily lean air-fuel mixture. Who is right? B Only How do you use a systematic approach to troubleshooting? Using your knowledge of automotive systems and a logical process of elimination to find the source of a problem. A(n) _______ is a condition where the engine does not accelerate normally when the gas pedal is pressed. Hesitation What causes "backfiring?" Air-fuel mixture igniting in the intake manifold or the exhaust system. Define the term dieseling. Occurs when the engine fails to shut off. All of the following are common engine performance problems except: Oil Leak If you have difficulty locating an engine performance problem, refer to a factory _________, which lists problem causes and corrections. Diagnosis Chart An automobile engine has a misfire problem. Technician A says type A misfires are severe enough to cause catalytic converter damage. Technician B says that "rpm at misfire" and "load at misfire" are misfire data produced by a scan tool when connected to the OBD II diagnostic link. Who is right? Both A & B A car is towed into a shop with a no-start problem. The engine cranks but will not fire and run on its own power. The car has a throttle body, fuel injected gasoline engine. Technician A says to check for spark and fuel first. Technician B says that the spark plugs should be removed first. Who is right? A Only A car has a hard starting problem. Technician A says the engine may have a faulty throttle position sensor. Technician B says this engine malfunction may be caused by a faulty coolant temperature sensor. Who is right? Both A & B A vacuum leak is detected in an automotive engine. Technician A says the leak will produce a banging sound at low engine rpms. Technician B says an intake manifold vacuum leak will make the engine run rough and increase idle rmps. Who is right? B Only An automotive engine has a no-start problem. Technician A says this condition may indicate an ignition system malfunction. Technician B says this problem may indicate a fuel system problem. Who is right? Both A & B An automotive engine has a stalling problem. Technician A says this problem may be due to a low idle speed setting. Technician B says this problem may be due to a severe engine vacuum leak. Who is right? Both A & B An automotive engine won't start. Technician A says you should first look in the engine compartment for obvious signs of trouble. Technician B says an exhaust gas analyzer should be used first to diagnose the engine problem. Who is right? A Only A(n) _______ or ________ is a metallic tapping or light knocking sound that usually occurs when the engine accelerates under load. Pinging; Spark Knock Vapor lock occurs when the gasoline is cooled and forms a gel, preventing fuel flow and engine operation. False A vacuum leak is a common cause of rough idling. True Technician A says stalling may occur while the engine is idling. Technician B says stalling may occur after cold starting. Who is right? Both A & B An engine is brought into the shop with a dieseling problem. Technician A says this may be caused by a high octane fuel. Technician B says this may be the result of an overheated engine. Who is right? B Only An engine has poor fuel economy. Technician A says this problem may be the result of a leaky fuel line. Technician B says this problem may be caused by a rich air-fuel mixture. Who is right? Both A & B A fuel injected engine misses and emits heavy black smoke. Technician A says this problem normally indicates an emission control system malfunction. Technician B says this problem may indicate a faulty engine temperature sensor. Who is right? B Only A car has a low brake pedal problem. Technician A inspects the brake adjusters. Technician B looks for a maladjusted master cylinder push rod. Who is right? Both A & B An automobile has a metal-on-metal grinding sound when the brakes are applied. Technician A inspects the brake linings. Technician B looks for a leaking wheel cylinder. Who is right? A Only An automobile has a spongy brake pedal. Technician A checks to see if the brake pad linings are too thin compared to specs. Technician B bleeds the brake system. Who is right? B Only Brake dust has accumulated on an automobile's wheel brake assemblies. Technician A uses a brake vacuum machine to remove this dust. Technician B uses compressed air to remove this dust. Who is right? A Only Cleaning hydraulic brake system parts in cold soak solvent is recommended. False What are the three methods for bleeding a vehicle brake system? Manual, Pressure, Vacuum How much fluid should typically be in a master cylinder? Brake Fluid Level Should Be 1/4"(6m) from the top of the reservoir Technician A says a scan tool will usually test the action of major ABS components by energizing them. Technician B says that a scan tool does not have this capability. Who is correct? A Only Technician A says that you must set the sensor air gap on some vehicles. Technician B says that the air gap between the sensor and trigger wheel needs to be increased each year the vehicle is in service. Who is correct? A Only A scan tool shows a problem with the modulator pump motor. Technician A says to check for power to the motor from the ABS control module. Technician B says if no power is reaching the motor to check the wiring between the control module and the motor. Who is correct? Both A & B Which of the following cannot be checked with a scan tool? Break Lining Condition The wheel speed sensors produce ac _____ that correspond to wheel and tire speed. Signals In addition to the brake warning light in the instrument cluster and the sensor trigger wheels, list and describe