State of Michigan Engine Performance and Tune Up Practice Test

These questions are part of the practice quiz. Start practicing

• Which device is responsible for managing engine performance and emissions by processing sensor data?
• In a vehicle equipped with OBD-II showing poor performance and a flashing check engine light, what fault is most likely?
• Higher than normal NOx emissions may be caused by which of the following?
• What diagnostic approach helps locate a leaking intake manifold gasket?
• When the engine vacuum is low but steady, which ignition timing condition is most consistent?
• What is the difference between short-term fuel trim (STFT) and long-term fuel trim (LTFT)?
• Which tool is used to check ignition coil resistance?
• Which component is responsible for regulating idle speed by controlling airflow at idle?
• What tool is used to measure compression in a cylinder?
• During a cooling system pressure test, which components are checked for leaks?
• Which test is used to identify valve, seat, piston, or ring leaks?
• Which vehicles are designed to go into a closed-loop operation?
• Which statement best describes a returnless fuel system?
• What effect would a fouled spark plug have hydrocarbon emissions?
• Which component is responsible for recirculating exhaust gas into the intake?
• The Powertrain Control Module firmware resides in which type of memory?
• What is the typical effect of a vacuum leak on the air-fuel mixture?
• Which condition can cause a higher than normal HC reading during an emissions test?
• Which statement correctly describes evaporative system monitoring in OBD-II compared to OBD-I?
• A P0301 code refers to which issue?
• The computer must receive inputs from which source for proper idle speed control motor operation?
• The Powertrain Control Module contains which type of memory for its firmware?
• Exhaust leaks can affect which readings, potentially causing incorrect diagnoses?
• Name a coolant system problem that does not involve the thermostat.
• Why should exhaust leaks be checked before diagnosing performance problems?
• What is the primary purpose of an engine performance tune-up?
• During cylinder leakage testing, bubbles in the radiator indicate which issue?
• Name two common ignition system components.
• Which component is part of the evaporative emission control system?
• At wide-open throttle, the powertrain control module reverts to which mode and fuel mixture?
• Which test method is described for checking intake vacuum leaks?
• Which sensor monitors fuel vapor pressure in the evaporative system?
• A tech is test driving a vehicle with a diagnose scan tool; the reading for the throttle position sensor would be described as?
• Which type of EFI injects fuel directly into the combustion chamber?
• In TPS voltage monitoring, which value is associated with near wide-open throttle?
• In closed-loop operation, what parameter does the PCM primarily use to adjust the air-fuel ratio?
• Which condition is a likely cause of a no-start in a DIS ignition system?
• Which condition is a potential effect of excessive ignition timing?
• During closed loop operation, a reading of 450 to 500 millivolts from the O2 sensor indicates what condition?
• When a customer reports low power, which of the following could be causes?
• Which type of fuel injection injects fuel into the intake port near the valve?
• A car with DIS will not start. Which fault is most likely?
• How can a dirty air filter affect performance?
• If the oxygen sensor indicates a lean condition, what should the engine control unit do?
• During a cylinder leakage test, air escaping through the throttle body indicates a leak at which component?
• Which statement correctly differentiates MAF and MAP sensors?
• What is the function of the PCV check valve?
• What is the function of the EGR valve?
• When spark knock occurs, what action does the engine control unit typically take?
• The on-board microcomputer receives signals from
• What is a leak-down test used for?
• Where should a vacuum hose connected to the P vacuum port be connected in relation to the throttle plate?
• How is fuel pressure controlled in an EFI system?
• What is the purpose of the knock sensor?
• If knock is detected and the ECU retards timing, which sensor initiated this action?
• Which device is used to measure compression in a cylinder during diagnostics?
• A reading of 8 volts on meter 2 while cranking would indicate which condition?
• Which of the following is a common cause of a lean condition indicated by the Check Engine light?
• The device that integrates engine performance and emissions control is which?
• Besides misfires, which condition can lead to catalytic converter overheating?
• When monitoring the TPS signal voltage, what indicates a smooth increase to about 4.5 V?
• Which tune-up step is performed last according to a typical sequence?
• What is the typical tune-up sequence?
• White colored spark plugs typically indicate which condition?
• If the ignition timing will not advance past base timing, what is a likely condition?
• The engine management system uses oxygen sensor data to regulate the air-fuel ratio during which mode?
• Which instrument is commonly used to observe PCM signal waveforms during diagnosis?
• When testing the Powertrain Control Module, what type of meter should you use?
• A plugged catalytic converter will cause the engine vacuum to
• Jumping the a+b terminals in the diagnose connector is used to
• Which component burns HC and CO into CO2 and H2O?
• If the timing chain or belt is jumped or broken, which indicators might be observed?
• Which action is typically performed first during a standard tune-up?
• What is the basic purpose of ignition timing?
• Which of the following is a common symptom of a failing fuel injector?
• Which statement describes the throttle body injection (TBI) system?
• Which is a sign of a vacuum leak?
• An engine coolant temperature sensor that is out of range will most likely cause which issues?
• What is the function of the EGR valve?
• What does the upstream O2 sensor monitor, and why is it important for fuel control?
• A lean air-fuel mixture could be caused by which condition?
• During a tune-up, what is the recommended inspection order for belts and hoses?
• A spark plug malfunction would appear as?
• A faulty EGR valve that leaks exhaust gas into the intake manifold when the engine is idling can cause which symptoms?
• Compression test shows 75 psi dry and 80 psi wet on cylinder 4, while others are 140 psi. What does this indicate?
• In a returnless fuel system, where is fuel pressure regulated?
• Which of the following describes the normal voltage range for the throttle position sensor at mid-position?
• What is the primary purpose of the evaporative fuel control system?
• What is the typical replacement interval for spark plugs?
• Injector pulse width is best described as
• What is the PCV system's purpose?
• If cylinder 4 shows low compression due to valve sealing issues, which of the following is most likely true?
• What safety measures should you follow when performing tune-ups?
• Which component is commonly involved in eliminating high idle due to a leak or IAC fault?
• A plugged catalytic converter will cause which vacuum behavior?
• A compression test is used primarily to assess which engine condition?
• What does the downstream oxygen sensor monitor?
• What does the engine coolant temperature (ECT) sensor provide to the PCM?
• The EGR system is designed to
• During ignition timing work on some vehicles, what must be done to the ignition timing system?
• A weak ignition coil would most likely cause which symptom?
• If ignition primary circuit is open, which diagnostic step is most appropriate?
• On an OBD II system, a loose gas cap is likely to cause which indicator to illuminate?
• Which condition increases NOx production in combustion engines?
• What issues can high ethanol content fuel cause?
• What is the function of the camshaft position sensor?
• A reading of 1 V on meter number 1 during cranking indicates which test should be performed?
• Which symptom would most likely indicate a misfiring spark plug?
• An exhaust gas oxygen sensor sends signals to the engine computer primarily during which operating condition?
• Emission control systems are installed on engines to reduce which three exhaust products?
• How does engine temperature affect ignition timing in many engines?
• What is a common cause of spark plug fouling?
• What is the effect of increasing injector pulse width?
• All of the following correctly describe fuel evaporation control
• The component that captures and stores fuel vapors in the evaporative system is the?
• Backfires through the throttle body are most likely caused by which condition?
• Regarding fault codes, which statement is true?
• What is the purpose of a fuel pressure test?
• When the engine operates in open loop, how is the fuel mixture controlled?
• In a carbureted engine, what is the effect of a high float level?
• Which system is monitored by OBD-II for emissions but was not the focus of OBD-I diagnostics?
• What is the primary function of a catalytic converter?
• What is the function of the throttle position sensor (TPS)?
• What is a common cause of spark plug fouling?
• Which condition could cause an O2 sensor to read rich when the engine is actually lean?
• In diagnosing a misfire on a single cylinder, which ignition component is most commonly at fault?
• Describe a basic test to check for intake vacuum leaks.
• A car runs rough and backfires through the throttle body; which component is likely faulty?
• If the misfire is detected by the OBD-II system during operation, the check engine light may flash. Which fault is most consistent?
• What is the primary purpose of the oxygen sensor in an engine management system?
• Name a common cause of catalytic converter overheating.
• Which factor can contribute to higher NOx emissions?
• Which ratio is considered stoichiometric for gasoline engines in closed-loop operation?
• Which sensor data does the PCM use to adjust fueling during warm-up?
• Which sensor provides the PCM with information about the amount of air entering the engine for proper fuel metering?
• What steps would you take to diagnose a rough idle?
• When base timing is reached and no advance occurs, which mode is commonly engaged to protect the engine?
• Which system is designed to route crankcase vapors back to the intake to be burned, reducing emissions?
• The powertrain control module uses the throttle position sensor (TPS). The related variable determines what parameter in this simple model?
• At operating temperature and around 2000 rpm, the oxygen sensor reading indicates which condition?
• The EFI configuration that sprays fuel into the intake manifold near the intake valve is called what?
• If the voltage spike is not high enough on one cylinder, what is the most likely source of the problem?
• During a cylinder leakage test, if air escapes through the throttle body, which component is leaking?
• Which diagnostic difference exists between OBD-I and OBD-II regarding evaporator systems?
• A high float level or heavy float in a carbureted engine causes what air-fuel condition?
• Which component is used to purge fuel vapors from the canister into the engine intake?
• A P0300 diagnostic trouble code indicates ...?
• What is the purpose of the injector balance test?
• Define spark knock and one common cause.
• Differentiate MAF and MAP sensors.
• What does a fuel pressure regulator do?
• Electronic fuel injection is best described as which of the following?
• Which of the following could cause engine detonation?
• The carbon canister is part of which system?
• What is the target air-fuel ratio for stoichiometric gasoline engines in closed-loop operation?
• Which component's condition should be checked first during a tune-up?
• What is OBD-II readiness status?
• When the microcomputer monitors air flow, what is the resulting action?
• Which of the following is not a typical symptom of a failing fuel injector?
• What does the EVAP system do?
• If the oxygen sensor signals a lean condition, what is the typical ECU response?
• After verifying a slow cranking complaint, what should you do next?
• Which component is part of the evaporative emissions control system?
• At wide-open throttle, which statement best describes the typical fuel control mode?
• If a car will not start because of spark, what is the first thing you should check?
• Which statement best describes a safety precaution when working near electrical components during a tune-up?
• An electronic fuel injected system that sprays into the throat of intake is called?
• Which sensor provides the PCM with air mass information in most modern engines?
• What common fault can cause a high idle?
• During a diagnostic drive, a reading of intermediate throttle position indicates the throttle is at mid-range. Which option best describes this?
• Increases EGR flow at constant speeds would cause what change in the fuel injector pulse width?
• What is the purpose of a cooling system pressure test?
• Which test measures fuel delivery performance by assessing fuel pressure?
• A car that has a strong fuel odor is most likely due to which issue?
• What does a P0300 diagnostic trouble code indicate?
• In diagnostic procedures, shorting the A+B terminals is used to
• If the air-fuel mixture is overly rich, which problem is commonly observed?
• Which condition could lead an infrared HC analyzer to show a higher than actual reading?
• Which of the following best describes common symptoms of a misfire?
• Which parameter does the engine control module primarily use to adjust idle speed?