Engine Performance Test 2

b. 4 to 9

A fuel system that runs at 35 to 50 psi should draw around _____ amps of current. a. 2 to 4 b. 4 to 9 c. 9 to 13 d. 15 to 18

b. hard starting

A loss of residual fuel pressure immediately after engine shutdown could cause ______. a. surging b. hard starting c. loss of power at high speed d. excessive emissions

b. B only

A rich air/fuel mixture is being discussed. Technician A says oxygen content in the exhaust will be high. Technician B says the O2 sensor voltage will be high. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. False

All modern vehicles use a threaded, removable gas cap. a. True b. False

c. kerosene

All of the following are aromatic hydrocarbons EXCEPT: a. benzene b. xylene c. kerosene d. toluene

d. neither A nor B

Injector cleaning is being discussed. Technician A uses a wire brush to clean the tips of the injectors. Technician B soaks the injector in cleaning solvent. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

d. All the answers are correct.

Methanol can be made from ______. a. wood b. coal c. natural gas d. All the answers are correct.

c. remove the negative battery cable

The first step in removing a fuel tank is to ______. a. drain the tank b. loosen the retaining straps c. remove the negative battery cable d. raise the vehicle on a lift

a. under the car

The fuel filter on a modern car is typically mounted ______. a. under the car b. on the end of the fuel rail c. on the intake manifold d. on the side of the engine block

d. fuel line freeze-up

The volatility of gasoline affects all the following performance characteristics EXCEPT: a. cold starting and warmup b. vapor lock c. performance at higher altitudes d. fuel line freeze-up

a. 0, 1

The voltage signal from most O2 sensors varies between _____ and _____ volt(s). a. 0, 1 b. 2, 3 c. 3, 5 d. 9.6, 12

b. B only

When emptying a fuel tank, Technician A drains the fuel into plastic antifreeze containers then caps them tightly to prevent leaks. Technician B drains the fuel into approved gasoline storage containers. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. 30,000 miles (48,280 km)

Which of the following is a typical fuel filter replacement interval? a. 30,000 miles (48,280 km) b. 100,000 miles (160,000 km) c. 50,000 miles (80,470 km) d. 15,000 miles (24,140 km)

c. momentarily enrich the mixture

A sudden increase in TP voltage tells the PCM to _____ to prevent hesitation and stumbling during acceleration. a. advance base ignition timing b. retract the IAC valve pintle c. momentarily enrich the mixture d. open the EGR valve

b. B only

A vehicle with a leaking nylon fuel supply line is being repaired. Technician A says replace the nylon fuel line with a section of double-wall steel fuel line, using short lengths of rubber fuel hose and screw clamps to connect to the filter and fuel tank to the steel line. Technician B says use an OEM nylon fuel line assembly. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Diesel engines are being discussed. Technician A says diesel fuel contains less energy than gasoline. Technician B says diesel engines produce more torque than gasoline engines. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. two

Each fuel injector has a _____-wire connector. a. one b. two c. three d. four

d. All the answers are correct.

Excessive alcohol in the fuel may cause ______. a. lack of power b. stalling c. no starts d. All the answers are correct.

a. A only

Fuel lines are being discussed. Technician A says when installing flexible tubing, always use new clamps. Technician B says ordinary rubber hose may be used to replace a kinked steel fuel line. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Gas cap testing is being discussed. Technician A says the tester applies twenty inches of vacuum to the cap and measures its rate of leakage. Technician B says if the wrong adapter was used, the cap will fail the test even if it is good. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Hydrogen-fueled vehicles are being discussed. Technician A says hydrogen [H2] can be made from natural gas. Technician B says hydrogen can be made from water. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. replace the pressure regulator

If liquid gasoline is found in the fuel pressure regulator vacuum hose, you should ______ to repair the problem. a. replace the vacuum hose b. replace the pressure regulator c. replace the fuel pump d. clean out the vacuum hose

c. both A and B

Octane ratings are being discussed. Technician A says most modern engines are designed to use regular grade gasoline. Technician B says to use high octane gasoline only when an engine was designed to use it. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

d. 26,000

On a modern common rail diesel (DI) direct injection system fuel pressure is typically ______ psi. a. 26 b. 260 c. 2,600 d. 26,000

a. True

On modern vehicles, the fuel pump is shut off when the air bag is deployed. a. True b. False

d. SFI (sequential fuel injection)

Only _____ meets the requirements of OBD II regulations. a. MPI (multipoint injection) b. TBI (throttle body injection) c. TPI (tuned port injection) d. SFI (sequential fuel injection)

c. voltmeter

Operation of an O2 sensor is checked with a(n) _____. a. ammeter b. ohmmeter c. voltmeter d. all answers are correct

d. neither A nor B

Preliminary checks are being discussed. Technician A says to run specific fuel injection tests first. Technician B says most driveability concerns are caused by PCM-related problems. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Short-term and long-term fuel trim readings are being discussed. Technician A says a scale of 0 to 255 is used. Technician B says percentage is used. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A checks GDI (gasoline direct injectors) injectors with a pulse tester. Technician B test GDI injectors with an ohmmeter. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says that dedicated vehicles are those designed to use one particular type of fuel. Technician B says that bi-fuel vehicles can operate solely on an alcohol-based fuel or unleaded gasoline, or a mixture of the two, which gives the driver flexibility and convenience when refilling the fuel tank Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. 1; 10

Typical fuel injector pulse widths range from _____ to _____ milliseconds. a. 1; 10 b. 10; 100 c. 100; 1,000 d. 1,000; 10,000

a. inside the fuel tank

Where is the fuel pressure regulator on a returnless fuel system? a. inside the fuel tank b. on the end of the fuel rail c. on the fuel filter inlet d. on the fuel line near the fuel tank

d. All the answers are correct.

Which of the following are characteristics of burning LP-gas? a. quicker starting b. fewer hydrocarbons c. less carbon monoxide d. All the answers are correct.

d. IAC motor (idle air control)

Which of the following is NOT a component of a throttle-by-wire system? a. accelerator pedal position sensor b. throttle position sensor c. throttle control motor d. IAC motor (idle air control)

b. propane

Which of the following is considered natural gas? a. kerosene b. propane c. gasoline d. diesel fuel

c. both A and B

A/F ratio sensors are being discussed.Technician A says the output voltage of these sensors is much higher than a conventional O2S (oxygen sensor). Technician B say when the output of an A/F ratio sensor is looked at with an OBD-II generic scan tool, the voltage range will appear the same as a conventional O2S sensor, 0 to 1 volt. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. True

All current gasoline fuel tank filler tubes have a built-in restrictor that prevents the entry of the larger leaded fuel delivery nozzle at gas pumps. a. True b. False

c. high carbon dioxide emissions

All the following are emission-related characteristics of diesel fuel EXCEPT: a. high sulfur content b. particulate emissions c. high carbon dioxide emissions d. high nitrogen oxide emissions

d. decreased compression ratio

All the following are factors that cause knock EXCEPT: a. hotspots in the cylinder b. carbon on the pistons c. forced air into the cylinders d. decreased compression ratio

d. Tetraethyl lead is added to gasoline to decrease the vapor pressure

All the following statements are correct EXCEPT: a. During a Reid vapor test, fuel is heated to 100 degrees Fahrenheit (38 degrees Celsius) b. Vapor pressure is measured in psi c. The more volatile a fuel is, the easier it will vaporize d. Tetraethyl lead is added to gasoline to decrease the vapor pressure

b. 200

An LP [propane]-powered vehicle stores its fuel in pressurized tanks at approximately ______ psi. a. 25 b. 200 c. 500 d. 2,000

d. fuel pressure gauge

An injector balance test requires an injector pulse tester and a ______.. a. tachometer b. noid light c. lab scope d. fuel pressure gauge

c. 600°F (316°C)

An oxygen sensor must heat up to approximately _____ before functioning in its closed loop mode. a. 200°F (93°C) b. 400°F (204°C) c. 600°F (316°C) d. 800°F (427°C)

c. both A and B

Idle learn procedures for ETC (throttle-by-wire)-equipped vehicles are being discussed. Technician A says the learn or relearn procedure should be completed anytime the PCM has been replaced or updated, or after the throttle body has been cleaned or replaced. Technician B says the system does not need to relearn if the battery has been disconnected. The system will automatically go through the procedure when the engine is restarted.Who is correct? a. A only b. B only c. both A and B d. neither A nor B

d. O2S (oxygen sensor)

In closed loop, the PCM adjusts the pulse width according to inputs from a variety of sensors, but primarily the _____. a. TP (throttle position) b. ECT (engine coolant temperature) c. IAT (intake air temperature) d. O2S (oxygen sensor)

b. B only

Residual fuel pressure is being discussed. Technician A says remove the fuel filter hose and apply compressed air to the fuel line to push the residual fuel back into the fuel tank. Technician B says to relieve the residual pressure by connecting a fuel gauge with a bleed valve to the Shrader valve. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

d. neither A nor B

Technician A says TBI systems use top fuel-feeding injectors. Technician B says PFI systems use bottom fuel-feeding injectors. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says a defective injector may cause cylinder misfiring at idle speed. Technician B says restricted injector tips may result in acceleration stumbles. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says a motor converts electrical energy into mechanical energy. Technician B says an engine converts chemical energy into mechanical energy. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says a pressure relief valve closes if the fuel supply line is restricted and pump pressure becomes very high. Technician B says the check valve in the pump prevents fuel from draining out of the fuel system and back into the fuel tank. This helps holds residual pressure in the fuel lines after the pump is turned off. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says a rich air/fuel ratio may be caused by low fuel pump pressure. Technician B says a rich air/fuel ratio may be caused by a defective engine coolant temperature sensor. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says an SFI is more efficient than an MFI injection because fuel is injected only when the intake valve is open, so the fuel can't condense when the intake valve is closed. Technician B says an MFI injection system can shut down the injector for a misfiring cylinder, preventing catalytic converter overheating. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says an intake manifold vacuum leak may cause a high idle speed. Technician B says a dirty IAC bypass passage will not cause the idle speed to be below specifications. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says diesel engines consume less fuel per mile than a gasoline engine of the same size. Technician B says diesel engines provide more torque than a gasoline engine of the same size. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says in a returnless fuel system, the pressure regulator is mounted on the fuel rail. Technician B says in a returnless fuel system the pressure regulator, fuel sender, and pump assembly are combined in one unit inside the fuel tank. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says increasing the Reid vapor pressure (RVP) will help the engine start easier in cold weather. Technician B says increasing the RVP will increase the possibility of fuel boiling (vapor lock) in summer driving. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says on some vehicles the fuel pressure is monitored by a fuel rail pressure sensor and the output of the fuel pump is controlled by the PCM through pulse-width modulation. Technician B says all fuel pumps on late-model vehicles are controlled by the PCM according to inputs received on the CAN bus and other specific sensors.Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says that reformulated gasoline produces a leaner air-fuel mixture. Technician B says that RFG generates more carbon dioxide. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says the IAC counts should change when the A/C compressor is turned on and off. Technician B says if the scan tester indicates zero IAC counts, there may be an open circuit between the PCM and the IAC motor. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says the air/fuel ratio of a GDI (gasoline direct injection) engine can be as high as 60 to 1. Technician B says because the air/fuel ratios are so lean, GDI engines require lower compression ratios to prevent detonation. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

d. neither A nor B

Technician A says the computer uses the TP sensor and ECT sensor signals to determine the amount of air entering the engine in a speed-density system. Technician B says the computer uses the TP sensor and oxygen sensor signals to determine the amount of air entering the engine in a speed-density system. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says the fuel pressure regulator in a PFI system senses manifold vacuum and continually adjusts the fuel pressure to maintain a constant pressure drop across the injector. Technician B says the pressure regulator in a PFI system is designed to provide a constant pressure to the fuel injector throughout the range of engine loads and speeds. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says the gas cap is equipped with a pressure release valve that opens if there is excess vapor pressure in the fuel tank. This prevents tank ballooning. Technician B says the gas cap is equipped with a vacuum relief valve that opens if there is an excessive amount of vacuum in the fuel tank. This prevents tank collapse. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Technician A says the inertia switch has a reset button that must be depressed for at least one second before the pump will operate again. Technician B says the inertia switch is triggered by the ABS control module. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says throttle body cleaner may be used to clean the IAC motor internal components. Technician B says on some vehicles, IAC motor damage can occur if the pintle is cleaned with throttle body cleaner. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says throttle-by-wire systems (ETC) eliminate the need for a cruise control actuator. Technician B says ETC also allows the PCM to be more effective when limiting engine and vehicle speeds. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A says when the ECT sensor detects low engine temperature, the PCM decreases the injection pulse width. Technician B says when the TP sensor detects a sudden increase in throttle angle, the PCM increases the injectors' pulse width. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Technician A says white smoke in the exhaust of a diesel engine can be the result of a cylinder misfire in a warm engine. Technician B says blue smoke in the exhaust of a diesel engine can be caused by scored cylinder walls. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Technician A uses a low-impedance test light to check for an injector pulse. Technician B uses a noid light to check the injector pulse. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. lab scope

The activity of an O2 sensor is best monitored with a ______. a. lab scope b. scan tool c. logic probe d. noid light

d. All the answers are correct.

The fuel pressure regulator can be located _____. a. on the throttle body b. on the fuel rail c. inside the fuel tank d. All the answers are correct.

d. cold starting

The longest injector pulse width occurs during ______. a. deceleration b. idle c. acceleration d. cold starting

CKP (crankshaft position sensor)

The most important sensor in the fuel management system is _____. a. MAF (mass airflow) b. MAP (manifold absolute pressure) c. oxygen sensor d. CKP (crankshaft position sensor)

d. oxygen sensor

The throttle body of a port fuel injected engine may include any of the following components EXCEPT: a. idle air control motor b. single or double bores with throttle plates c. throttle position sensor d. oxygen sensor

c. All injectors receive the same PCM commands simultaneously

Which of the following is NOT representative of sequential fuel injection systems? a. They have one injector per cylinder b. Injectors are located in the intake manifold ports c. All injectors receive the same PCM commands simultaneously d. None of the answers is correct.

d. restricted fuel filter

Which of the following problems could NOT cause the fuel pressure to drops off quickly after the engine and ignition are turned off. a. leaking injector b. internally leaking fuel pump check valve c. internally leaking fuel pressure regulator d. restricted fuel filter

a. leaking pressure regulator vacuum line

Which of the following would not cause the fuel pressure to drop to zero immediately after engine shut down? a. leaking pressure regulator vacuum line b. leaking fuel pressure regulator c. leaking fuel pump check valve d. leaking fuel injector

a. lean

While cranking a fuel injected engine and holding the accelerator to the wide-open throttle position, the air/fuel mixture will be ______. a. lean b. normal c. rich d. stoichiometric

c. both A and B

While discussing common rail fuel injection systems: Technician A says the individual injectors are activated by the high pressure present in the fuel rail. Technician B says some late-model CR systems have an intensifier in the injector that allows for an increase in fuel pressure. Who is correct? a. A only b. B only c. both A and B d. neither A nor B