Deck 8: Diesel Fuel and Low Pressure Fuel Systems

Question 1

Diesel fuel with a cetane number (CN) of 50 or greater has which of the following characteristics?

A)It is 1-D and burns quickly.
B)It is 1-D and burns slowly.
C)It is 2-D and burns quickly.
D)It is 2-D and burns slowly.

Answer 1

A

Question 2

Technician A says that placing a fuel heater in a filter housing is the best way to prevent wax and ice crystals from restricting fuel flow. Technician B says that ethanol can be used to dissolve wax and prevent water from crystalizing in fuel filters. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Answer 2

A

Question 3

What effect does gasoline contamination have on diesel fuel?

A)It lowers the auto-ignition temperature of the fuel.
B)It lowers the flash point of the fuel.
C)It lowers the cloud point of the fuel.
D)It shortens the ignition delay time of the fuel.

Answer 3

B

Question 4

What effect does increasing fuel temperature have on diesel engine operation?

A)It increases power output.
B)It reduces power output.
C)It seems to increase fuel consumption because the fuel occupies more volume.
D)It causes fuel to become more viscous, resulting in poor fuel atomization.

Question 5

Which of the following is the result of water contaminating fuel?

A)Lower fuel density.
B)Fuel system components rusting or corroding.
C)Cleaner injector nozzles.
D)Cooler injector operation.

Question 6

Technician A says straight vegetable oil (SVO) can be burned in a diesel engine without causing any long-term problems for engine durability. Technician B says SVO will damage injectors. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 7

Technician A says that adding a little gasoline to diesel fuel will help a diesel engine start faster in cold weather, reduce combustion noise, and improve power output. Technician B says that adding gasoline to diesel fuel will make starting worse, increase combustion noise, and accelerate fuel system wear. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 8

Technician A says that 2-D fuel provides the most power and best fuel economy for an on-highway diesel engine. Technician B says that 1-D is the best fuel for producing power and good fuel economy. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 9

Technician A says that diesel fuel's low volatility is why so many diesel fuel pump islands appear to have a lot of spilled fuel. Technician B says that fuel spills at diesel pump islands are more common than those at gasoline pumps because truck drivers are careless when refueling. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 10

Which of the following properties does B5 diesel fuel have?

A)It is red and has 5% sulfur content.
B)It is 5% animal fat.
C)It has 5% petroleum content.
D)It has 5% biologically based content.

Question 11

Which color is fresh, good-quality 2-D diesel fuel when it is commercially retailed?

A)Red.
B)Clear.
C)Blue.
D)Dark green.

Question 12

Technician A says that coolant is used to heat fuel in fuel-water separators. Technician B says that electrical heating elements keep water and wax from plugging the filter in a fuel-water separator. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 13

Technician A says that adding alcohol to diesel fuel is a good practice because it keeps fuel from waxing when it is cold and it improves engine starting. Technician B says wax in fuel should be removed at the refinery because it causes owners to make complaints about low power in hot weather. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 14

The temperature at which wax crystals begin to form in diesel fuel is referred to as its _______.

A)cloud point
B)pour point
C)CN
D)viscosity index

Question 15

Which of the following methods is best suited to treating diesel fuel that contains free water while minimizing any potential damage to the fuel system?

A)Add alcohol to keep the water dissolved and to prevent freezing.
B)Heat the fuel with a fuel heater to prevent icing.
C)Separate the water from the fuel through coalescence.
D)Treat the fuel with kerosene.

Question 16

A primary fuel filter will typically have ___________.

A)a nominal micron rating of less than 5 microns
B)an efficiency rating of 50% with a 10-micron rating
C)a micron rating of 2-10 microns
D)a micron rating of up to 100 microns

Question 17

Technician A says that the primary filter helps extend the life of the secondary filter. Technician B says that the primary filter is located between the engine's high-pressure injection system and the secondary filter. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 18

Technician A says that a float sensor can be used in a filter housing to measure the level of water, to determine when the filter should be drained. Technician B says that a probe in the bottom of a fuel filter, which measures the difference between the conductivity of water and fuel, is used to switch on the water-in-fuel warning lamp. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 19

Technician A says that primary filters typically use chemically treated paper filter media with a micron rating of more than 10 microns. Technician B says that synthetic filter media is used to separate bound, or coalesced, water from fuel inside a primary filter. Who is correct?

A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question 20

Which of the following is the best factor to use when determining whether a fuel filter should be replaced?

A)Time in service.
B)Distance traveled.
C)Operating conditions.
D)Restriction measurement.

Question 21

Which of the following petroleum derivatives is the more favored alternative to biologically based diesel engine fuels?

A)Crude oil"
B)Distillates"
C)Kerosene
D)Light hydrocarbons"

Question 22

Who establishes diesel fuel standards?

A)SAE (Society of Automotive Engineers)"
B)ATA (American Trucking Association)"
C)TMC (Truck Maintenance Council)
D)ASTM (American Society for Testing Materials)"

Question 23

Petroleum diesel fuel is defined in ASTM standard:

A)D975"
B)D976"
C)D6751
D)B6751"

Question 24

In the US, diesel fuel properties are regulated by the Environmental Protection Agency (EPA) and:

A)ASTM (American Society for Testing Materials)"
B)SAE (Society of Automotive Engineers)"
C)ATA (American Trucking Association)
D)TMC (Truck Maintenance Council)"

Question 25

Which ASTM (American Society for Testing Materials) diesel fuel grade has impurities and other characteristics that will quickly damage on-highway engines?

A)1-D"
B)2-D"
C)3-D
D)4-D"

Question 26

In the oil refining process of boiling and vapor separation, where does diesel fuel come from?

A)Middle distillates"
B)Bottom distillates"
C)Top distillates
D)End distillates"

Question 27

Diesel fuel is also produced by liquefying hydrocarbon gases, such as methane, and modifying the chemical structure of the hydrocarbon molecules and is manufactured by using a chemical process invented in Germany during the 1920s called the:

A)Haber process"
B)Diesel-Daimler reaction"
C)Otto cycle
D)Fischer-Tropsch reaction"

Question 28

What color is aviation fuel dyed?

A)Red"
B)Blue"
C)Yellow
D)Amber"

Question 29

Technician A says that older diesel fuel darkens and turns cloudy as it absorbs gasoline. Technician B says that old diesel fuel develops a varnish or turpentine-like odor. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question 30

The EPA began to limit the sulfur content of on-road diesel fuel in 1993 to 0.05% mass or 500 ppm maximum, which mandated the production of:

A)low-sulfur diesel (LSD) fuel"
B)sulfur free diesel fuel"
C)biodiesel
D)ultra-low-sulfur diesel (ULSD)"

Question 31

Which of the following is the result of water contaminating fuel?

A)Lower fuel density."
B)Fuel system components rusting or corroding."
C)Cleaner injector nozzles.
D)Cooler injector operation."

Question 32

Technician A says that adding a little gasoline to diesel fuel will help a diesel engine start faster in cold weather, reduce combustion noise, and improve power output. Technician B says that adding gasoline to diesel fuel will make starting worse, increase combustion noise, and accelerate fuel system wear. Who is correct?

A)Technician A"
B)Technician B"
C)Both A and B
D)Neither A nor B"

Question 33

Technician A says that diesel fuel's low volatility is why so many diesel fuel pump islands appear to have a lot of spilled fuel. Technician B says that fuel spills at diesel pump islands are more common than those at gasoline pumps because truck drivers are careless when refueling. Who is correct?

A)Technician A"
B)Technician B"
C)Both A and B
D)Neither A nor B"

Question 34

Which of the following diesel fuel performance requirements can minimize wear?

A)Starting ease"
B)Lubricating properties"
C)Efficient power production
D)Low noise production"

Question 35

Which one of the following is pure biodiesel and can be used as fuel?

A)B10"
B)B20"
C)B40
D)B100"

Question 36

Which of the following is NOT an advantage of biodiesel?

A)No aromatic content"
B)Enhanced lubricating properties"
C)Contains little or no sulfur
D)Low cetane number"

Question 37

Which of the following is NOT an environment benefit of using biodiesel?

A)67% reduction in unburned HCs"
B)48% reduction in CO"
C)47% reduction in PM emissions
D)68% reduction in NOx emissions"

Question 38

Which of the following is NOT a disadvange of using biodiesel?

A)Fuel system incompatibility"
B)Energy input"
C)Reduction in unburned HCs
D)Aromatic content"

Question 39

One notable exception to the emission benefits of biodiesel is that it can produce higher levels of ______ from some engine families.

A)HC (Hydrocarbons)"
B)CO (Carbon Monoxide)"
C)PM (Particulate Matter)
D)NOx (Oxides of Nitrogen)"

Question 40

What is the cetane number (CN) for ultra low sulphur diesel (ULSD) #2D?

A)30"
B)60-70"
C)40
D)48-65"

Question 41

Diesel fuel is classified according to its viscosity and density. Which diesel fuel is the most viscous?

A)1D"
B)2D"
C)3D
D)4D"

Question 42

What is used to measure the API number that corresponds to the specific gravity of fuel?

A)Fuel hydrometer"
B)Manometer"
C)Spectrometer
D)DMM (Digital Multimeter)"

Question 43

Two technicians are describing the process to determine the API number of a diesel fuel. Technician A says that you use a specific diesel fuel hydrometer to measure the fuel's temperature and API number. Technician B says that because the density of a fuel is affected by temperature, the corrected API value provides the API number that the fuel would have at room temperature. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question 44

A naturally high-cetane fuel, such as 1-D, produces less power and increases fuel consumption relative to:

A)5D"
B)2D"
C)3D
D)4D"

Question 45

Which of these diesel fuel additives prolong storage life; minimize oxidation; reduce gums, resins, and sediments; and improve injector spray patterns?

A)Dispersants"
B)Stabilizers"
C)Metal deactivators
D)Biocides"

Question 46

Which of the following CN booster compounds can increase the CN of the fuels by as much as seven points in small concentrations (0.2%)?

A)Octane based"
B)Nitrate based"
C)Hydrogen based
D)Oxygen based"

Question 47

Which of the following can cause can cause abrasive wear and fuel filter plugging?

A)High sulfur"
B)Aromatics"
C)Ashphaltenes
D)Naphthalenes"

Question 48

The service life of injection pumps, injectors, fuel transfer pumps, and other fuel system components can be prolonged through the use of:

A)dispersants"
B)lubricants"
C)stabilizers
D)metal deactivators"

Question 49

Two diesel technicians are discussing diesel fuel corrosion inhibitors. Technician A says that due to the sulfur content of diesel fuel, it can lighten materials made of copper and bronze, forming a gooey coating on these parts. Technician B says that because many fuel tanks and lines are made of steel, the interior and both metal fittings and filter housings can rust or corrode. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question 50

Two technicians are discussing the low pressure fuel system. Technician A says that it supplies an adequate volume of fuel at the correct pressure to the high-pressure injection system. Technician B says that it prevents wax gelling and regulates fuel temperature. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question 51

What material is not suitable for diesel fuel tanks in mobile applications?

A)Aluminum"
B)Plastic"
C)Steel alloy
D)Fiberglass"

Question 52

Gasoline will easily vaporize and burn at:

A)-45°F"
B)45°F"
C)55°F
D)-55°F"

Question 53

What minimum pressure must be maintained to enable the injectors to operate on an HPCR fuel system?

A)100 to 170 psi"
B)25 to 35 psi"
C)58 to 160 psi
D)10 to 20 psi"

Question 54

Most fuel system wear takes place with particle contamination of ______ in diameter

A)1-2 microns"
B)4-5 microns"
C)5-7 microns
D)10-20 microns"

Question 55

What can be used to inspect for air in the suction side of the fuel system?

A)In-line site glass"
B)A metal canister"
C)An old used filter
D)Rubber hose"

Question 56

Which of the following concerns will NOT be caused by air in fuel?

A)Low-power"
B)Engine will run rough"
C)Hard to start
D)Poor fuel economy"

Question 57

Technician A says to avoid over servicing filters, but measure filter restriction to obtain the best indication of when a filter requires replacement. Technician B says that to measure a filter restriction, use a vacuum gauge connected with a T-fitting or service port between the transfer pump and secondary filter. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question 58

It is particularly important to _______ because many systems today use very little fuel return to the tank, which can carry air and vapors back to the tank.

A)replace filters regularly"
B)use only OEM filters"
C)check for air
D)bleed air"

Question 59

During a primary fuel filter suction-side pressure test, a slight negative pressure is observed. What is the MOST LIKELY cause?

A)Suction-side restriction"
B)This is a normal condition"
C)Pressure-side restriction
D)Defective left pump"

Question 60

You are measuring secondary filter output pressure. Technician A says that air can lead to the injector tips of newer high-pressure nozzles being damaged. Technician B says that you connect the gauge to the outlet side of the secondary filter. Who is right?

A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"