Section 4 ASE Style Quiz (A8)

Which of the following statements about fuel trim are correct? - Positive fuel trim numbers indicate a rich exhaust condition - Negative fuel trim numbers indicate a rich exhaust condition - Negative fuel trim numbers are a command for increased fuel delivery - Short term fuel trim responds to long term fuel trim trends

Negative fuel trim numbers indicate a rich exhaust condition

Which of the following is not a cause of low fuel pressure? - Restricted fuel filter - Obstructed return line - Stuck fuel pump check valve - Low pump RPM

Obstructed return line

A vehicle displays a LTFT (long term fuel trim) of +16%: Which of the following is the most likely cause? a. A lazy O2 sensor b. Faulty fuel pressure regulator c. Contaminated MAF sensor d. Restricted air filter

Contaminated MAF sensor

The pre-catalyst O2 sensor on an OBD II equipped engine is consistently reading below 450mv. Which of these is the most likely cause? - Cracked exhaust manifold - Leaking fuel injector - Leaking MAP sensor vacuum hose - Shorted O2 sensor wiring

Cracked exhaust manifold

Technician A says a speed density system uses RPM and a mass air flow sensor to calculate fuel delivery. Technician B says a mass air flow sensor is used to measure pressure in the intake manifold. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Neither A nor B

Technician A says both magnetic pulse generators and Hall-effect sensors produce AC voltage. Technician B says both magnetic pulse generators and Hall-effect sensors produce square-wave patterns. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Neither A or B

Technician A says that the spark plugs have the only air gap in a distributor type ignition. Technician B says the plug gap solely determines firing voltage. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Neither A or B

When viewing an ignition pattern a high firing line on one cylinder is noted. Technician A says that a grounded plug wire could cause this. Technician B says that a poor rotor-to-cap connection could cause this. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Neither A or B

Which of the following is used when performing an EVAP system leak test? - Compressed air - Oxygen - Nitrogen - CO2

Nitrogen

All of the following are considered tailpipe pollutants except: - HC (hydrocarbon) - CO (carbon monoxide) - NOx (nitrogen oxide) - O2 (oxygen)

O2

Changes in STFT (short term fuel trim) are primarily driven by what sensor? - MAF sensor - MAP sensor - O2 sensor - ECT sensor

O2 sensor

All of the following statements about O2 sensors are correct except: - O2 sensors generate a small voltage in response to exhaust oxygen content - O2 sensors compare exhaust gas oxygen content to the outside air - O2 sensors can operate with very lean air-fuel mixtures - O2 output voltage should switch rapidly from low to high and back again

O2 sensors can operate with very lean air-fuel mixtures

Which device will properly measure ignition system operating voltages over time? - Oscilloscope - Dwell meter - Spark tester - All of the above

Oscilloscope

Secondary voltage reserve is necessary for all of the following except: - High load conditions - Increased spark plug gap - Rich fuel mixtures - High secondary wire resistance

Rich fuel mixtures

Which of the following EFI (electronic fuel ignition) systems is the most accurate? - MPI (multipoint fuel injection) - SFI (sequential fuel injection) - TBI (throttle body fuel injection) - CMFI (central multipoint fuel injection)

SFI

All of the following EFI (electronic fuel injection) systems are used on modern engines except: - GDI (gasoline direct injection) - PFI (port fuel injection) - TBI (throttle body injection) - CPI (central port injection)

TBI

A vehicle has a rough idle after an on-car fuel injection cleaning was performed. Technician A says the computer needs to relearn fuel strategies. Technician B says the injector cleaning did not remove all of the fuel deposits. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says a BAS (belted alternator starter) hybrid system provides stop-start operation to save fuel. Technician B says a BAS hybrid can propel the vehicle by the motor/generator alone. Who is correct? - Technician A - Technician B - Neither A or B - Both A and B

Technician A

Technician A says a broken MAP (manifold absolute pressure) sensor vacuum hose will cause a rich condition. Technician B says a broken MAP sensor vacuum hose will cause a lean condition. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says a contaminated MAF sensor will cause a lean condition. Technician B says a contaminated MAF sensor will cause a rich condition. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says high resistance in the coil primary circuit can reduce coil voltage output. Technician B says high resistance in the coil primary is necessary to boost secondary voltage output. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says incorrect spark plug heat range can cause cylinder misfire. Technician B says that too high of a heat range spark plug can cause detonation. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says lean air-fuel ratios require increased current flow across the spark plug gap for complete combustion. Technician B says rich air-fuel ratios require increased current flow across the spark plug gap to prevent misfires. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says that variable intake manifold runners force air through small runners at low RPM. Technician B says small runners decrease the speed of the airflow. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says the HO2S (hot oxygen) monitor must run before the catalyst monitor can run. Technician B says the catalyst monitor can run independently of the status of the HO2S monitor. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says the ignition system must change spark timing based on engine RPM. Technician B says maximum spark advance is needed under heavy engine loads. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

While discussing O2 sensors on OBD II systems, Technician A says post-catalytic converter sensors are used to verify converter operation. Technician B says the post-converter sensors are used for fuel trim adjustments. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician A

Technician A says E85 and M85 are interchangeable. Technician A says only specially equipped vehicles can use E85. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says NTC (negative temperature coefficient) engine coolant sensors have high resistance at high temperatures. Technician B says a NTC sensor has high resistance at low temperatures. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says TWC (three way catalytic) converters require a fresh air supply for proper operation. Technician B says the TWC require an alternating rich/lean mixture for proper operation. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says a higher fuel octane rating helps improve fuel economy. Technician B says higher octane fuels are not required for most modern engines. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says an exhaust backpressure gauge is required to diagnose a restricted exhaust system. Technician B says a small amount of restriction or backpressure is normal. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says open loop operation means the PCM is monitoring and correcting fuel control based on the O2 sensor. Technician B says some systems go into open loop during wide-open throttle. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says slight distortions in the spark line indicate an incorrect air-fuel mixture. Technician B says slight distortions or turbulence is normal. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says that a pressure reading of 10 psia is equivalent to 10 psig. Technician B says a pressure reading of 10 psia is considered vacuum. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

Technician A says turbocharged equipped engines require special maintenance procedures. Technician B says turbocharged equipped engines require special start up and shut down procedures. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Technician B

All of the following statements about OBD (on-board diagnostics) II are correct except: - OBD II equipped vehicles have a generic DLC - The main purpose of OBD II is emissions monitoring - The powertrain control module is reprogrammable - The MIL illuminates if emissions exceed 125% of the Federal standard

The MIL illuminates if emissions exceed 125% of the Federal standard

A magnetic-pulse type CKP (crankshaft position) sensor shows infinite resistance when tested with a DMM. Which of the following statements are correct? - The sensor winding is shorted - The sensor resistance is correct - The sensor winding is open - This sensor cannot be checked for resistance

The sensor winding is open

Ignition dwell refers to the: - Time that current flows in the primary side of the coil - Total current value in the primary side of the coil - Peak primary voltage - Secondary firing voltage level

Time that current flows in the primary side of the coil

All of the following statements about turbochargers are correct except: - Turbocharger compressors spin at high RPM - Turbochargers provide boost at very low engine RPM - The waste gate controls turbo boost - Variable geometry turbochargers do not use a waste gate

Turbochargers provide boost at very low engine RPM

A four-cylinder engine with a waste-spark ignition system has ________ ignition coils. - One - Two - Four - Does not use an ignition coil

Two

All of the following are examples of variable resistor sensors except: - Throttle position sensor - EGR position sensor - Accelerator position sensor - Vehicle speed sensor

Vehicle speed sensor

The MIL (malfunction indicator lamp) on an OBD II equipped vehicle is flashing at idle. Technician A says this indicates a Class A misfire is occurring. Technician B says this indicates that catalyst damage may occur. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

All of the following statements about superchargers are correct except: - Superchargers are driven by the engine crankshaft - Supercharges may require special lubrication - Intercoolers are not used with superchargers - Some vehicles use superchargers and turbochargers together

Intercoolers are not used with superchargers

All of the following statement about gasoline lead additive are correct except: - Lead poisons catalytic converters - Lead increases gasoline octane - Leaded fuels are still available as automotive fuels - Very small amounts of lead are still present in fuel

Leaded fuels are still available as automotive fuels

All of the following are problems associated with a plugged or restricted PCV (positive crankcase ventilation) system except: - Oil leaks - Oil in air cleaner housing - Lean air/fuel mixture - Oil sludging

Lean air/fuel mixture

All of the following ways to depressurize the fuel system are correct except: - Using a fuel pressure gauge attached to the fuel test port - Removing the fuel pump fuse and running the engine - Loosening the fuel filter connection - Removing the fuel pump relay and running the engine

Loosening the fuel filter connection

Which of the following is the ideal air-fuel ratio? - 12:1 - 14.7:1 - 13.5:1 - 15.8:1

14:7:1

Which of the following considered an indicator of good engine efficiency? - High HC - High O2 - High CO2 - High CO

High CO2

The EGR (exhaust gas recirculation) system is designed to reduce which exhaust emission? - HC - CO - NOx - CO2

NOx

Glow plugs in a diesel engine are used to: - Ignite the air/fuel mixture - Heat the fuel before injection - Heat the intake air - Warm the engine coolant

Heat the intake air

Technician A says the gas cap is part of the emission control system. Technician B says the gas cap is part of the fuel supply system. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

A vehicle with a distributor ignition system is being inspected for a misfire. Technician A says the spark plug wire insulation may be leaking. Technician B says how the spark plug wires are routed could cause a misfire. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

Technician A says a chassis dynameter is necessary to perform the I/M 240 test. Technician B says the I/M 240 test measures pollutant levels at idle and under load. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

Technician A says diesel fuel is rated for the speed at which the engine operates. Technician B says diesel fuel is rated for the seasonal temperatures in which it is used. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

Technician A says engines with throttle-by-wire systems do not need throttle idle air control systems. Technician B says throttle-by-wire eliminates cruise control actuators. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

Technician A says most late model vehicles mount the fuel pump in the fuel tank. Technician B says some vehicles use a frame mounted fuel pump. Who is correct? - Technician A - Technician B - Both A and B - Neither A or B

Both A and B

Which of the following is not used in modern ignition systems as a crankshaft position sensor? - Hall-effect sensor - Magnetic pulse generator - Contact points - LED sensor

Contact points

Oxygen storage is necessary for limiting which exhaust emissions? - CO and HC - NOx and CO - HC and CO2 - O2 and CO

CO and HC

Which of the following statements about emissions are correct? - When O2 goes up CO goes up - CO2 will be high at lambda - NOx goes down with engine temperature - HC decreases due to misfires

CO2 will be high at lambda

Which of the following is not a pre-combustion emission control? - EGR valve - EVAP canister - Electronic spark control - PCV valve

EVAP canister

All of these conditions require increased injector pulse width except: - Cold engine start - Increased electrical system load - Engine deceleration - Open loop conditions

Engine deceleration

The PCM may turn the fuel pump circuit off for all of the following reasons except: - Excessive vehicle speed - SRS deployment - Excessive fuel pressure - High speed deceleration

Excessive fuel pressure

Which of the following fuel system tests is not generally performed on GDI (gasoline direct injection) systems? - Fuel pressure - Fuel volume - Injector resistance - None of the above

Fuel volume