Diesel Test 3 and final
When a fuel heater is used in a diesel fuel sub-system, what is the maximum temperature the fuel should be heated to? 125 degrees Fahrenheit 75 degrees Fahrenheit 90 degrees Fahrenheit 110 degrees Fahrenheit
90 degrees Fahrenheit
A small quantity of water is drained from a water separator equipped with a WIF sensor that has produced no service alert. Immediately after, a WIF alert is signaled. What should you do first? Check the fuel tanks for water Replace the WIF sensor Replace the water separator Clean the WIF probes
Clean the WIF probes
Which of the following diesel fuels is most commonly used to fuel highway trucks in North America? #2D red #1D clear #2D clear #2D blue
#2D clear
In a current direct injected diesel engine governed at 2000 rpm, what droplet size range must the injection system produce? 10 - 100 microns 200 - 500 microns 1 - 10 microns 100 - 200 microns
10 - 100 microns
Where is the ideal location for peak cylinder pressure to occur on the power stroke? TDC 15 degrees ATDC 45 degrees ATDC 90 degrees ATDC
15 degrees ATDC
What is the maximum sulfur content in a diesel fuel classified as ultralow sulfur (ULS) in North America? 50 ppm 15 ppm 300 ppm 500 ppm
15 ppm
If a 4-stroke cycle diesel engine is run at 2000 rpm, how much real time is required for a single revolution of the engine? 5 milliseconds 60 milliseconds 15 milliseconds 30 milliseconds
30 milliseconds
When multi-orifice nozzles are used in hydromechanical diesel engines, what would be a typical NOP value? 2000 psi 3000 psi 5000 psi 800 psi
3000 psi
When adjusting a low spring injector nozzle NOP, what should be done to increase opening pressure? turn adjusting screw CCW subtract shims add shims turn adjusting screw CW
add shims
What is the main ingredient found in a diesel fuel conditioner? alcohol cleaning additives pour point depressant cetane improver
alcohol
What substance is commonly added to truck diesel fuel tanks to prevent winter freeze up? antifreeze ethylene glycol lcohol dispersants
alcohol
If injector valve-to-nozzle body clearance in a multi-orifii injector is greater than specification, which of the following values would increase? NOP back leakage residual line pressure peak pressure
back leakage
What is required to test the NOP of a hydraulic injector? bench test fixture OEM software ultrasonic bath pressure pulse, line transducer
bench test fixture
Which of the following terms describes the amount of heat energy in a fuel? calorific value fire point volatility cetane number
calorific value
A substance that enables a chemical reaction without itself undergoing any change is known as a: fraction catalyst polymer reactant
catalyst
Which is the most efficient method of separating the highest fractions found in crude petroleum? thermal cracking catalytic cracking distillation vaporization
catalytic cracking
What two principles are used by most fuel water separators to remove water from fuel? absorption and condensation emulsification and absorption positive filtration and straining centrifugal force and gravity
centrifugal force and gravity
How is an engine that is electronically managed, controlled? computer electrical switches hydraulic governor mechanical governor
computer
Which of the following would indicate the lowest engine rpm? peak torque high idle engine lug droop curve
engine lug
What do most mechanical governors on truck engines use to sense engine speed? fuel pressure thrust collar oil pressure flyweights
flyweights
What pumping principle is used on transfer pumps on a majority of diesel engines today? centrifugal reciprocating plunger swash plate gear
gear
Which of the following terms means the same thing as top engine limit (TEL) in a highway truck engine? high idle peak torque overrun rpm rated speed
high idle
In a fleet operation, when should truck drivers be instructed to refill the fuel tanks? immediately after returning from a trip when the ambient temperature is lowest before beginning their outbound trip never, it should be done by a yard jockey
immediately after returning from a trip
Which of the following sensors would least likely be used in a current fuel subsystem? inductive pulse sensor water-in-fuel sensor fuel pressure sensor charging pressure sensor
inductive pulse sensor
Fuel injected per crank angle degree in a diesel fuel system is known as: injection quantity atomization rate delivery rate injection rate
injection rate
Which of the following tools can be used to pull a flanged hydraulic injector nozzle from a cylinder head? screwdriver injector heel bar injector sleeve broach pry bar
injector heel bar
Which of the following governing classifications would allow the accelerator pedal in a truck diesel engine to respond like that in an automobile? variable speed isochronous limiting speed all-speed governor
limiting speed
What is the main reason VCO nozzle geometry has become common today? easier to recondition lower manufacturing costs lower NOx emissions lower HC emissions
lower HC emissions
What is the main advantage of a low spring design over a high spring type in a typical multi-orifice injector assembly? ease of setting NOP improved emissions mass of moving parts is reduced lower maintenance costs
mass of moving parts is reduced
How much mechanical leverage can result when a piston throw on the crankshaft forms a 90 degree angle to the piston on its downstroke? minimum none maximum 50% of maximum
maximum
Which of the following explains why piezo actuators respond faster to injector driver signals than equivalent solenoid actuators? lighter in weight they use data bus driven signals respond to wireless driver inputs mechanical movement takes place without having to build a magnetic field
mechanical movement takes place without having to build a magnetic field
The precise control of injected fuel quantity in a diesel engine is known as: pressurization measuring atomization metering
metering
When testing for fuel subsystem inlet restriction which of the following is recommended? plumb an air filter restriction gauge into the primary filter pad negative pressure gauge reading in inches of mercury positive pressure gauge reading in inches of water positive pressure gauge reading in inches of mercury
negative pressure gauge reading in inches of mercury
What is the geometric relationship between the sectional area of the nozzle seat, and that of the nozzle pressure chamber known as? NOP to line pressure ratio peak pressure to NOP ratio seat to shank ratio nozzle differential ratio
nozzle differential ratio
When a multi-orifice injector nozzle is closed, what seals the nozzle assembly from the engine cylinder? nozzle line nut nozzle sac nozzle shank nozzle valve seat
nozzle valve seat
When a hydromechanical governor throttle is snapped (to full fuel request) under no-load, engine rpm temporarily exceeds the high idle speed. What is the term used to describe this condition? overrun deadband hunting top end limit
overrun
What is the source of 70% of the energy consumed in North America? coal nuclear fusion petroleum hydro electricity
petroleum
When fuel condenses on the piston crown during injection, which of the following can result? pitting pre-ignition pinging detonation
pitting
What can result from a water-in-fuel condition when the secondary filter is capable of entrapping particulate as small as one micron? water absorption into fuel filtering media failure filter burst plugged filter and shutdown
plugged filter and shutdown
When priming a primary fuel filter during a routine service, which of the following is best practice? pour fuel only into filter outlet port pressurize the fuel tanks with shop air pour fuel only into filter inlet ports crank the engine for 30 seconds
pour fuel only into filter inlet ports
What is the reason for advancing injection timing as engine speed increases? more air in engine cylinder less air in engine cylinder real time available for combustion decreases real time available for combustion increases
real time available for combustion decreases
What pumping principle is used by hand-actuated priming pumps on most current diesel fuel subsystems? centrifugal gear reciprocating plunger vane
reciprocating plunger
Why does retarding injection timing tend to produce higher HC emissions? increases combustion temperatures increases ignition lag increases injection lag reduces time available for combustion
reduces time available for combustion
When a leak is identified in an aluminum fuel tank, what do most manufacturers recommend? repair with silicone fill tank with water and weld replace tank steam tank, fill with nitrogen and weld
replace tank
What pressure is dead volume fuel held at in pump-line-nozzle (PLN) diesel fuel systems? residual line pressure delivery valve opening pressure charging pressure nozzle opening pressure
residual line pressure
Which of the following components would NOT be under suction when the engine is running? secondary filter pickup tube fuel tank primary filter
secondary filter
What is a fuel water separator unable to remove from the fuel routed through it? coalesced water free state water semi-absorbed water emulsified water
semi-absorbed water
Which of the following components is a requirement with a high spring injector design? shims to set NOP spindle to transmit spring force to nozzle valve double pressure chamber an accumulator chamber
spindle to transmit spring force to nozzle valve
In a typical multi-orifice, hydraulic injector, what force holds the nozzle valve on its seat? fuel pressure combustion pressures spring force compression pressures
spring force
What force(s) hold an EHI nozzle needle seated in a standard CR system when the engine is stationary and there is no measurable rail pressure? hydraulic pressure only spring pressure only electrical pressure only combined spring and electrical force
spring pressure only
When you are asked to repair weld an aluminum diesel fuel tank, which of the following is recommended? steam and fill with nitrogen steam and fill with oxygen fill with fuel before welding fill with water before welding
steam and fill with nitrogen
What would double gasketing of a primary fuel filter most likely cause? vapor lock sucking air into fuel fuel leakage no-start condition
sucking air into fuel
When attempting to remove a seized injector spacer washer, which of the following tools would be recommended? hammer and punch heel end of an injector heel bar taper reamer tapered end of an injector heel bar
tapered end of an injector heel bar
Which of the following is NOT generally considered to be a desirable feature specified to a truck fuel tank? temperature insulated aluminum construction cylindrical shape located in airflow
temperature insulated
Technician A says that the best way to prime a diesel fuel system is to charge shop air pressure to the fuel tank and crank the engine unit it fires. Technician B says that when a fuel subsystem is fitted with an ECM-managed priming pump, this should always be used to prime the engine after a service. Who is correct? Technician B only Neither A nor B Both A and B Technician A only
Neither A nor B
Technician A says that EHIs are ECM switched to open and close. Technician B says that EHIs are opened when pressure in the CR rises to the nozzle opening pressure. Who is correct? Both A and B Neither A nor B Technician B only Technician A only
Technician A only
Technician A says that it is common for Caterpillar HEUI fuel systems to use a centrifugal type fuel transfer pump. Technician B says that a double-acting fuel subsystem transfer pump moves fuel on the push and pull strokes. Who is correct? Technician A only Technician B only Neither A nor B Both A and B
Technician B only
What is a typical NOP value of the multi-orifice nozzle used in an EUI (electronic unit injector)? 5000 psi 3000 psi 800 psi 2000 psi
5000 psi
What would the phase angle be on a port-helix metering injection pump fueling a 4-stroke cycle diesel engine? 60 degrees 30 degrees 120 degrees 360 degrees
60 degrees
Which of the following ingredients and conditions are required to produce photochemical smog? HC+NOx+sunlight+time PM and VOCs coal dust and carbon dioxide sulfur, PM and high humidity
HC+NOx+sunlight+time
What electrical principle is used by the injector nozzle valve motion sensors (NVMS) in Bosch VE fuel systems? induction Hall-effect piezoelecticity potentiometer
Hall-effect
What type of high pressure pump do Caterpillar use in their CR fuel systems? Inline piston External gear Radial piston Port-helix
Inline piston
In which of the following applications would a hydromechanical port-helix metering pump be found in an EPA MY 2017 compliant onhighway application? LTL tractor Pick up and delivery van Reefer powerplant Linehaul tractor
Linehaul tractor
Which city in the United States has been noted to have a major problem with photochemical smog? Houston, TX Los Angeles, CA Detroit, MI Chicago, IL
Los Angeles, CA
What is another way of saying popping pressure? line pressure charging pressure NOP peak pressure
NOP
What tailpipe emission from a diesel engine is likely to increase under lean burn operation? CO NOx PM VOCs
NOx
When a reduction catalytic converter is used on a current diesel engine, which of the following emissions would it be attempting to minimize? carbon dioxide NOx CO sulfur dioxide
NOx
Which two compounds are necessary for the formation of photochemical smog? NOx and HC nitrogen and oxygen H2O and SO2 sulfur and carbon dioxide
NOx and HC
Technician A says that desired rail pressure in a CR fuel system is signaled by the rail pressure sensor. Technician B says that actual rail pressure in a CR fuel system is calculated by the ECM. Who is correct? Both A and B Neither A nor B Technician A only Technician B only
Neither A nor B
Technician A says that the ECMs used on commercial truck applications of diesel CR are networked on the CAN-C bus. Technician B says that the diesel engine ECMs used on automobile and light truck applications of diesel CR are networked exclusively by the J1939 bus.Who is correct? Both A and B Neither A nor B Technician B only Technician A only
Neither A nor B
What is the maximum number of engine cylinders that can be fueled using a Bosch VE sleeve metering, rotary distributor pump? Eight Four Six Two
Six
When a Bosch EDC-VE fuel pump is used to fuel a V-configured, 6-cylinder engine, how many high pressure pipes are used to deliver fuel from the injection pump to the engine cylinders? One Six Three Two
Six
What moves the advance piston in electronically-managed versions of inlet metering, opposed plunger, rotary distributor injection pumps? Hall-effect sensor Spring force Fuel pressure Solenoid
Solenoid
What do some current engines use to assist closed crankcase ventilation (CCV) emissions? electrostatic oil separator (EOS) HC reduction catalyst oxidation catalyst gas-sealed crankcase
electrostatic oil separator (EOS)
Technician A says that the fuel shutdown device used on Bosch sleeve metering, rotary distributor pumps is known as ELAB. Technician B says that Bosch fuel shutdown solenoids latch when energized, preventing unwanted shutdown in the event of a loss of electrical power. Who is right? Technician A only Neither A nor B Both A and B Technician B only
Neither A nor B
What type of fuel system is used on EPA MY 2010 and later Cummins ISX engines? XPI HPI-TP CAPS EUI
XPI
When priming a new secondary filter, which method do most OEMs prefer you use? pour fuel only into filter outlet port a hand, electric, or integral primer pump pour fuel only into filter inlet ports pressurize the fuel tanks
a hand, electric, or integral primer pump
In a Bosch type sleeve metering rotary distributor pump what locks the distributor plunger into its position relative to the cam plate? interference fit weld a pin set screws
a pin
Which of the following is the most common method of shutting down an engine fueled by a hydromechanical port helix metering injection pump? energize shutdown solenoid choke off intake air de-energize shutdown solenoid control rack to no fuel
control rack to no fuel
What controls injected fuel quantity in an EDC managed, VE injection pump? NVMS start of injection solenoid cam lift dimension control sleeve solenoid
control sleeve solenoid
When a diesel engine is said to be hydromechanically managed, which of the following components would NOT be used? computer fuel transfer pump mechanical governor fuel injectors
computer
A plunger in a port-helix metering pump with a lower helix would produce which of the following timing characteristics? constant beginning, variable ending constant beginning, constant ending variable beginning, variable ending variable beginning, constant ending
constant beginning, variable ending
What component is responsible for managing plunger effective stroke? control rack camshaft delivery valve tappets
control rack
What component is directly responsible for moving the control rack in a mechanical port helix metering injection pump? governor speed control lever decompression lever camshaft
governor
What is the function of the flutes machined into a delivery valve? define delivery valve opening pressure define dead volume pressure seal the valve before it seats guide the valve in the delivery valve body
guide the valve in the delivery valve body
At what relative speed must a sleeve metering, rotary distributor injection pump be driven when used to fuel a 4-stroke cycle diesel engine, with 6 engine cylinders? engine speed two times engine speed half engine speed six times engine speed
half engine speed
At what relative speed must an inlet metering, opposed plunger injection pump be driven when used to fuel a 4-stroke cycle diesel engine, with 6 engine cylinders? two times engine speed six times engine speed engine speed half engine speed
half engine speed
Which of the following would have the effect of advancing injection timing in an inlet metering, opposed plunger rotary distributor pump engine? low fuel load in pump chamber sticking fuel shutoff solenoid high fuel load in pump chamber high filter inlet restriction
high fuel load in pump chamber
When an inlet metering, opposed plunger rotary distributor pump is adapted for management by computer, which of the following terms best describes the system? high tech partial authority state of the art full authority
partial authority
Which of the following does most to define the residual line pressure value? swept volume of the retraction piston sectional area of the delivery valve length of the flutes peak injection pressure value
peak injection pressure value
Which type of multi-orifice injector nozzle sometimes uses an accumulator in place of a leakoff circuit? pencil injectors valve closes orifice (VCO) high spring injectors low spring injectors
pencil injectors
Which of the following types of injector are most vulnerable to damage when removing them for the engine cylinder head? poppet nozzles pencil nozzles flanged multi-orifii electrohydraulic injectors
pencil nozzles
A chemical process initiated by the absorption of light is known as what type of reaction? oxidation photochemical redux galvanic
photochemical
Which of the following best describes the type of injectors used with EDC-managed VE injection pumps? poppet electrohydraulic multi-orifii pintle
pintle
What is the uppermost part of a plunger used on a port helix metering pump known as? plunger leading edge vertical slot upper helix plunger lugs
plunger leading edge
What event begins the effective stroke in a port helix metering injection pump? port closure port opening delivery valve opening delivery valve closure
port closure
Which of the following terms means the same thing as static timing? ignition timing port closure timing injection timing port opening timing
port closure timing
What event causes pressure collapse to occur in the pump chamber of a port helix metering pump? port opening port closure delivery valve opening delivery valve closure
port opening
What event ends the effective stroke in a port helix metering injection pump? port opening injector closure port closure delivery valve closure
port opening
When a single pick-up tube is used on a pair of cylindrical fuel tanks mounted either side of a truck frame, which of the following is required? crossover pipe two return lines two transfer pumps auxiliary pump
crossover pipe
When water is present in the fuel tanks of a dual tank, single pickup fuel subsystem, where is it likely to settle? crossover pipe emulsify in the fuel in the pick-up tube on top of the tank
crossover pipe
Which of the following compounds is a commonly used diesel fuel ignition accelerator? propane cetane butane cyclohexanol nitrate
cyclohexanol nitrate
As pressure increases in the injection circuit, what happens to the emitted droplet sizing? increases in size becomes less aerated decreases in size becomes more aerated
decreases in size
What should be used to diagnose an air-in-fuel condition in a diesel fuel sub-system? on-board diagnostic software mercury manometer diagnostic sight glass ether
diagnostic sight glass
Which of the following port-helix metering pump, static timing procedures would provide the highest accuracy? high pressure timing pin electronic transducer and timing light
electronic
Convert one bar to an approximate psi value: 120 psi 15 psi 30 psi 60 psi
15 psi
When a port helix metering pump is phased to a 4-stroke cycle engine, how many times does the engine rotate through one complete pump revolution? 2 revolutions 180 degrees 4 revolutions 1 revolution
2 revolutions
Which of the following is another term used to describe the aqueous urea solution known as DEF? AdBlue dosing fuel ammonia urea
AdBlue
Technician A says that DPFs requiring fuel dosing can be managed by a dosing control module. Technician B says that DPF dosing cycles can be managed directly by the ECM. Who is correct? Neither A nor B Technician A only Both A and B Technician B only
Both A and B
Technician A says that an advantage of EHIs over standard hydraulic injectors, is the absence of injection lag. Technician B says that EHIs are capable of multipulse injections within a single cycle. Who is correct? Technician B only Both A and B Technician A only Neither A nor B
Both A and B
Technician A says that most Bosch CR high pressure pumps are lubricated with diesel fuel. Technician B says that Caterpillar CR high pressure pumps are lubricated with engine oil. Who is correct? Technician B only Both A and B Neither A nor B Technician A only
Both A and B
Technician A says that most hydromechanical rotary-distributor diesel injection pumps are used to fuel small bore engines. Technician B says that most hydromechanical rotary-distributor diesel injection pumps are used in older indirect injection (IDI) diesel applications. Who is correct? Technician B only Neither A nor B Technician A only Both A and B
Both A and B
Who regulates and sets emissions certification standards for highway diesel engine emissions in the state of California? California Trucking Association California Consumer Protection Agency California Air Research Board California Better Business Bureau
California Air Research Board
What force is used to hold the nozzle valve seated and closed on a typical CR-EHI when the engine is running? Electrical force only Combined spring and hydraulic force Spring force only Combined spring and electrical force
Combined spring and hydraulic force
What U.S. designed, diesel fuel injection pump outsold all other hydromechanical injection pumps manufactured world wide prior to the electronic age of diesel fuel management systems? M-100 VE DPA DB2
DPA
Identify the partial-authority control system used on inlet metering, opposed plunger, rotary distributor injection pumps that is sometimes found on agricultural and marine applications? V-MAC DPA-EPIC PEEC DDEC
DPA-EPIC
What term is used by Caterpillar on their CR EHIs to code their injection quantity calibration data for programming to the ECM? Cal code E-Trim quick response (QR) code Set point
E-Trim
What controls the metering valve in an electronically controlled version of an inlet metering, opposed plunger, rotary distributor pump? Metered fuel quantity ECM Engine rpm Fuel pressure
ECM
Which of the following will have most influence on the internal pump pressure of a Bosch EDC-VE injection pump? Throttle angle ECM control valve Control sleeve position Engine rpm
Engine rpm
What would happen if an EHI used on a Bosch CR fuel system stuck in an open position? Immediate engine shutdown Flow limiter would limit fueling Cylinder would overfuel Fuel rail pressure would collapse
Flow limiter would limit fueling
What is used to lubricate the high pressure radial piston pumps used on most Bosch CR fuel systems? Fuel Engine lubrication circuit Isolated oil supply Lubriplate
Fuel
What is use to advance the injection timing in a Bosch EDC-VE injection pump? Fuel pressure Centrifugal force Linear proportioning solenoid Latching solenoid
Fuel pressure
What manages control sleeve position in a Bosch EDC-VE fuel pump? ECM Fuel pressure Accelerator position Governor thrust washer
Fuel pressure
How many high pressure pumps are required to fuel a typical inline 6-cylinder, CR-fueled engine? Two Six Three One
One
What is used to switch an electrohydraulic injector (EHI) used in a typical CR fuel system? Fuel volume in accumulator Pulse width modulated signal Analog voltage charge Hydraulic distributor head
Pulse width modulated signal
Which name would be most closely associated with the invention of the inlet metering, opposed plunger rotary distributor pump? Ford General Motors Roosa Bosch
Roosa
Technician A says that CR EHIs with piezo actuators respond faster to energization by the injector drivers than those with solenoid actuators. Technician B says that current CR EHIs using piezo actuators tend to be slimmer and more compact than those with solenoid actuators. Who is correct? Both A and B Neither A nor B Technician B only Technician A only
Technician A only
Technician A says that EHI pressure at the beginning of an injection pulse should be closely equivalent to rail pressure. Technician B says that EHI pressure at the end of an injection pulse will have dropped off significantly. Who is correct? Technician B only Neither A nor B Both A and B Technician A only
Technician A only
Technician A says that a Bosch EDC controlled VE injection pump is a partial authority fuel management system. Technician B says that the EDC version of a Bosch VE pump continues to use a hydromechanical governor. Who is right? Technician B only Both A and B Technician A only Neither A nor B
Technician A only
Technician A says that an EHI with a piezo actuator is capable of breaking up a single injection cycle into up to 7 separate pulses. Technician B says that during a CR EHI multipulse injection cycle, the pressure rises through each successive pulse. Who is correct? Neither A nor B Technician A only Technician B only Both A and B
Technician A only
Technician A says that an inlet metering, opposed plunger rotary distributor pump cannot be used to fuel an engine with more than six cylinders. Technician B says that a Stanadyne opposed plunger, rotary distributor pumps used to be popular on older Ford and GM diesel engines. Who is correct? Both A and B Neither A nor B Technician B only Technician A only
Technician A only
Technician A says that carbon dioxide is classified as a greenhouse gas (GHG). Technician B says that water vapor produced by combusting HC fuel is not classified as a GHG because it is harmless. Who is right? Technician A only Technician B only Neither A nor B Both A and B
Technician A only
Technician A says that high pressure fuel can exit an injector nozzle at faster than the speed of sound. Technician B says that the most OEMs recommend electrohydraulic injectors (EHIs) to be field serviced using standard shop tools. Who is correct? Technician A only Both A and B Technician B only Neither A nor B
Technician A only
Technician A says that most hydromechanical rotary-distributor diesel injection pumps are used in indirect injection (IDI) applications. Technician B says that most hydromechanical rotary-distributor diesel injection pumps are used to fuel off-highway large bore engines. Who is correct? Technician B only Neither A nor B Both A and B Technician A only
Technician A only
Technician A says that most transfer pumps used on diesel CR systems are of the external gear type. Technician B says that most transfer pumps used on diesel CR systems use a non-positive pumping principle. Who is correct? Technician B only Neither nor B Technician A only Both A and B
Technician A only
Technician A says that the actuation voltage used to drive CR electrohydraulic injectors (EHIs) is typically around 100 volts when they use solenoid actuators. Technician B says that actuation voltage for EHIs that use piezo actuators is usually much higher than 100 volts. Who is correct? Both A and B Technician B only Technician A only Neither A nor B.
Technician A only
Technician A says that the outward movement of the opposed plungers in an inlet metering, rotary distributor pump depends on centrifugal force and therefore, pump rotational speed. Technician B says that plunger outboard travel on the same pump is limited by leaf spring stops. Who is right? Both A and B Neither A nor B Technician B only Technician A only
Technician A only
Technician A says that EDC VE distributor pump fuel systems use hydraulically-actuated injector nozzles. Technician B says that EDC VE fuel systems use nozzle valves equipped with nozzle valve motion sensors (NVMS). Who is correct? Technician B only Neither A nor B Technician A only Both A and B
Technician B only
Technician A says that EHIs are ECM-controlled but are limited by hard value NOPs. Technician B says that EHIs are used with current common rail (CR) and electronic unit injector (EUI) diesel fuel injection systems. Who is correct? Technician A only Technician B only Neither A nor B Both A and B
Technician B only
Technician A says that after replacing an injector spring on a hydraulic multi-orifice injector, it is good practice to set NOP 75 psi above specification. Technician B says that any time a hydraulic nozzle assembly is reassembled after bench testing, it is good practice to set NOP 150 psi above specification. Who is right? Both A and B Technician B only Technician A only Neither A nor B
Technician B only
Technician A says that electrohydraulic nozzles are used with late generation electronic unit injectors (EUIs). Technician B says that EHIs are used with diesel common rail (CR) systems. Who is correct? Technician B only Both A and B Technician A only Neither A nor B
Technician B only
Technician A says that fuel delivery timing in diesel CR fuel systems is limited by cam profile. Technician B says that a major advantage of diesel CR systems is their ability to manage fuel injection pressures without regard to engine rpm. Who is correct? Technician B only Both A and B Technician A only Neither A nor B
Technician B only
Technician A says that when an EDC-VE injection pump is used to fuel a four cylinder engine, four pumping plungers are used. Technician B says that EDC-VE pump plungers are actuated mechanically in the same way as the hydromechanical version. Who is right? Both A and B Technician B only Neither A nor B Technician A only
Technician B only
Technician A says that when fuel is being dosed to a DPF, the unit is being passively regenerated. Technician B says that when fuel is being dosed to a DPF, the unit is being actively regenerated. Who is correct? Neither A nor B Technician B only Technician A only Both A and B
Technician B only
While bench testing a multi-orifice injector nozzle, it rapidly pulses (chatter) as NOP is achieved. Technician A says that the nozzle seat is defective and should be replaced. Technician B says that nozzle chatter usually occurs only during bench testing. Who is right? Technician B only Both A and B Neither A nor B Technician A only
Technician B only
When considering EHI operation in a standard CR system while the engine is running but the actuator is not energized which of the following is true? the upper and lower pressure fields are at the same pressure rail pressure is present in the upper pressure field rail pressure is at nozzle needle seat all of the above
all of the above
Which is the stationary member of the pumping element used in a port helix metering pump? tappet barrel delivery valve body plunger
barrel
If an electronically controlled, variable timing device with a 20 degree timing window has to be static timed at 8 degrees BTDC, where can port closure occur? 8 degrees BTDC only 28 degrees BTDC only between 8 degrees BTDC and 12 degrees ATDC between 28 degrees BTDC and 8 degrees BTDC
between 28 degrees BTDC and 8 degrees BTDC
When the plunger on a port helix metering pump is at TDC, what else is true? delivery valve is open the pump chamber is at peak pressure cam is on base circle cam is on outer base circle
cam is on outer base circle
What defines plunger actual stroke in a sleeve metering rotary distributor pump? engine rpm cam plate plunger dimension control sleeve
cam plate
Where is the oil sump located in a port helix metering injection pump? tappet bay cambox flange housing charging gallery
cambox
In a typical port helix metering pump, which of the following components is rotated? tappets control rack pump barrel camshaft
camshaft
Which of the following tailpipe emissions were in 2008 been classified by the Supreme Court as a pollutant? oxides of nitrogen carbon dioxide sulfur dioxide carbon monoxide
carbon dioxide
At what pressure is the fuel gallery in a port helix metering pump charged? charging pressure leakoff circuit pressure nozzle opening pressure residual line pressure
charging pressure
In a running engine with a CR diesel system, what force(s) hold the nozzle needle seated when the actuator is not energized? combined spring and hydraulic force hydraulic force only spring force only electrical force only
combined spring and hydraulic force
What is used to lubricate the cambox components in a typical highway truck, port-helix metering injection pump? engine lubricating oil circuit lithium base, high temperature grease dedicated oil in the cambox sump fuel at charging pressure
engine lubricating oil circuit
Which of the following is going to have the most influence on internal VE pump fuel pressure at any given moment of engine operation? leak-off pressure engine rpm engine load injection pressures
engine rpm
If the fuel quantity actuator fails is a Bosch EDC controlled VE injection pump, which of the following would be the likely result? limp home mode operation engine shutdown engine derate no performance impact
engine shutdown
Which of the following explains the need to bar the engine only in its correct direction of rotation when timing a hydromechanical port-helix metering, injection pump to an engine? engine timing gear backlash factors delivery valve core seating calibration pointer location timing index location
engine timing gear backlash factors calibration pointer location timing index location
What is the advantage of piezo actuators over solenoid actuators? lower cost faster response lighter weight higher peak pressure potential
faster response
Convert 75 psi to bar and round to one of the following values: six bar two bar four bar five bar
five bar
What is used to lubricate the internal components of a Bosch sleeve-metering, rotary injection pump? engine oil from engine lubrication circuit dry sump dedicated supply of engine oil fuel
fuel
What is used to lubricate the internal components of an inlet metering, opposed plunger, rotary injection pump during operation? integral supply of engine oil fuel from the vane pump sealed bearings external supply of engine oil
fuel from the vane pump
If there was a complete electrical failure in an electronically-managed Bosch PE 8500 fuel pump, which of the following would result? shutdown strategy is initiated no engine restart after driver shuts down fuel rack defaults to no-fuel followed by immediate shutdown check engine light is illuminated
fuel rack defaults to no-fuel followed by immediate shutdown
In an operating port-helix metering injection pump, the term dead volume fuel refers to: fuel in the fuel pump chamber when the plunger is at the top of its stroke fuel held in the leak-off circuit fuel retained in the high pressure line between injection pulses fuel held in the fuel tank
fuel retained in the high pressure line between injection pulses
What happens to fuel in the pump chamber of a port-helix metering pump at port opening? fuel spills to the charging gallery fuel is re-routed to the transfer pump fuel is forced through the delivery valve fuel exits the fuel injector
fuel spills to the charging gallery
When the plunger metering recesses have minimum exposure to the spill port(s) through plunger stroke, how is the engine being fueled? half fuel no fuel idle fuel full fuel
full fuel
What is the function of the admission valve used in some diesel CR fuel systems? prevents fuel siphon from the rail on shutdown restricts flow area of the rail inlet holds rail pressure fuel away from nozzle seat until energized monitors fuel quantity entering the CR pump
holds rail pressure fuel away from nozzle seat until energized
What is the reason for using helices milled diametrically opposite on a plunger? increase fuel quantity hydraulic balance decrease fuel quantity improve lubrication
hydraulic balance
What force is used to move the advance piston in an inlet metering, opposed plunger rotary distributor pump that uses no computer controls? mechanical force centrifugal force hydraulic force spring force
hydraulic force
What does a variable timing device such as Econovance allow an ECM managing a Bosch 8500 injection pump to control? engine cylinder pressure exact moment of ignition injection timing advance centrifugal timing advance
injection timing advance
Which component(s) in an inlet metering, opposed plunger rotary distributor pump is moved by the advance piston? hydraulic head internal cam ring opposed plungers metering valve
internal cam ring
Which of the following is true about actual plunger stroke in a port helix metering injection pump? varies with fuel requirement varies with engine speed varies with manifold boost it is constant
it is constant
When an altitude compensator is used on the governor of a hydromechanical port-helix metering injection pump, what does it do? limits fueling (derates) at high altitudes uprates engine power on hills compensates for high oxygen density provides excess fuel at high altitudes
limits fueling (derates) at high altitudes
What is another way describing the linear magnet used as a rack position sensor in a Bosch 8500 fuel injection pump with an RE30 rack actuator? potentiometer latching solenoid linear proportioning solenoid Hall effect switch
linear proportioning solenoid
When adjusting static timing on a hydromechanical, port-helix metering injection pump to the engine, which of the following steps in the procedure should be performed last? remove the high pressure line remove the delivery valve core loosen pump drive plate to drive gear fasteners locate injection pump port closure
loosen pump drive plate to drive gear fasteners
Which of the following is true of a cooled exhaust gas recirculation (C-EGR) system on a truck diesel engine? lowers HC emissions improves engine efficiency lowers NOx emissions lowers both HC and NOx emissions
lowers NOx emissions
What is the function of an aneroid used in the governor of a port-helix metering injection pump? measures cylinder pressure meters fuel to the engine measure fuel injection pressure measures manifold boost
measures manifold boost
How is the engine being fueled when the vertical slot aligns with the spill port throughout plunger stroke? full fuel high idle fuel no fuel peak torque fuel
no fuel
In the Bosch PE 7100/8500 rack position sensor assembly, what is the difference between the measuring and reference coil windings? none, they are identically wound reference coil uses heavier gauge wire measuring coil uses larger number of windings reference coil has moving short circuit window
none, they are identically wound
Which of the following is NOT true of carbon monoxide? poisonous not classified as a pollutant combustible odorless
not classified as a pollutant
An inlet metering, opposed plunger rotary distributor pump is used to fuel an automotive V-8 diesel engine. How many delivery valves are used? four two eight one
one
How many high pressure pumping chambers are used in a typical inlet metering, opposed plunger rotary distributor injection pump? one two six four
one
How many high pressure pumping plungers are used in a Bosch type, sleeve metering, rotary distributor pump used to fuel a six cylinder engine? one six two four
one
Which of the following best describes the operating principle of the vane type transfer pumps used on Bosch rotary distributor pumps? variable cycle centrifugal constant velocity positive displacement
positive displacement
Which of the following best describes the operating principle of the vane type transfer pumps used on typical inlet metering, opposed plunger, rotary distributor pump? positive displacement constant velocity variable cycle centrifugal
positive displacement
A Bosch sleeve metering, rotary distributor pump fueled engine performs well at rated speed and load, but smokes under load at peak torque rpms. Which of the following might help correct this problem? negative torque control use fuel with higher CN derate high idle speed positive torque control
positive torque control
When considering standard EHI operation in a typical CR diesel fuel system, what happens the instant the actuator is energized? pressure builds in the lower pressure field pressure collapses in the lower pressure field pressure collapses in the upper (control) pressure field pressure builds in the upper (control) pressure field
pressure collapses in the upper (control) pressure field
When a typical CR-EHI is energized by the injector driver, which of the following occurs first? an injection pulse begins pressure in the valve control chamber collapses pressure in the valve control chamber rises an injection pulse
pressure in the valve control chamber collapses
What is used to move the fuel rack in an electronically-controlled, Bosch 8500 injection pump? rack actuator rack position sensor governor assembly hydraulic servo
rack actuator
What replaces the governor housing in an electronically controlled, port-helix metering injection pump? computer module rack actuator housing sensor housing transducer module
rack actuator housing
What component is used to control the actual rail pressure of a CR diesel fuel system? EHI solenoid accumulator rail pressure sensor rail pressure control valve
rail pressure control valve
Which of the following is the ECM output used to manage rail pressure at any given moment of operation in a diesel CR fuel system? rail pressure control valve rail pressure sensor EHI actuators rail flow limiter valve
rail pressure control valve
If actual rail pressure falls below desired rail pressure in a diesel CR system, which of the following should occur? rail pressure control valve directs more flow to the rail rail pressure control valve options more fuel to the return circuit rail flow limiter temporarily cuts flow to the EHIs rail flow limiter reduces flow to the EHIs
rail pressure control valve directs more flow to the rail
If the rail pressure limiter valve trips open in a typical CR fuel system, which of the following should be true? an EHI has stuck in the open position an EHI injection pulse is taking place actual rail pressure has fallen below desired rail pressure rail pressure has exceeded the highest specified system pressure
rail pressure has exceeded the highest specified system pressure
Which of the following correctly describes atomization? change of state from gas to liquid reduction of a liquid to minute droplets condensation of a gas to a liquid change of state from liquid to gas
reduction of a liquid to minute droplets
When a CR high pressure line is removed for any reason, which of the following steps is required practice by many engine OEMs? replace the high pressure line torque the line nuts to spec dress the sealing nipples on a grinder remove and replace the line nuts
replace the high pressure line
What is the function of the delivery valve used on an inlet metering, opposed plunger, type of rotary distributor pump? limits peak line pressure retains residual line pressure raises the nozzle opening pressure prevents high pressure spikes
retains residual line pressure
What is the function of an injector leak-off line? returns fuel to fuel tank vents fuel to atmosphere prevents fuel leakage into oil routes fuel to injector pressure chamber
returns fuel to fuel tank
Which of the following procedures would be the correct method of recalibrating fuel output from one pump element on a port-helix metering injection pump? advancing port closure timing increasing the charging pressure shimming the barrel flange rotating the barrel
rotating the barrel
Which of the following exhaust aftertreatment devices have been proven to significantly lower NOx emissions in highway diesel engines? selective catalytic reduction (SCR) particulate traps oxidation catalysts diesel particulate filters (DPFs)
selective catalytic reduction (SCR)
Which of the following procedures would adjust the phase angle of one pump element in a port-helix metering injection pump? shimming the barrel flange repositioning the control rack rotating the barrel shimming the fuel pump drive gear
shimming the barrel flange
What are the root words of smog? smile and ogle sulfur and ozone smoke and fog smolder and ogre
smoke and fog
What accounts for the response-delay of EHI nozzles using solenoid actuators compared with those using piezo actuators? solenoids require higher voltage solenoids must build and collapse magnetic fields before mechanical movement occurs piezo stacks draw more current piezo actuators open nozzles without having to move themselves
solenoids must build and collapse magnetic fields before mechanical movement occurs
Which of the following is another way of saying base timing when referring to multipulse capable, CR fuel systems? start of dosing pulse start of first injection pulse end of dosing pulse end of final injection pulse
start of first injection pulse
What type of smog is created primarily by the burning of heavy fossil fuels such as coal and heavy oils? particulate matter sulfur dioxide ozone photosynthetic
sulfur dioxide
Which of the following best explains why some OEMs state that the high pressure pipes used on CR systems should not be re-used? the seats deform to seal when initially torqued the engine warranty will voided the line nut hex is easily rounded out it is more profitable to the OEM to sell as many parts as possible
the seats deform to seal when initially torqued
What is used to signal engine position in a Bosch PE8500 pump with an RE30 rack actuator such as that used in a Mack Trucks V-MAC II managed engine? camshaft position sensor (CPS) crankshaft speed sensor (CSS) timing event marker (TEM) synchronous reference sensor (SRS)
timing event marker (TEM)
Which sensor must be removed from a V-MAC II, Bosch PE8500 fuel injection pump, to perform electronic static timing? transducer module rpm sensor timing event marker (TEM) camshaft position sensor (CPS)
timing event marker (TEM)
What is used to time a Caterpillar CR fuel system high pressure pump to the engine? timing pin spill timing high pressure phasing electronic timing
timing pin
Which of the following port-helix metering pump, static timing procedures would provide the least accuracy? electronic high pressure transducer and timing light timing pin
timing pin
When adjusting a high spring type injector nozzle NOP, what should be done to decrease opening pressure? turn adjusting screw CW add shims subtract shims turn adjusting screw CCW
turn adjusting screw CCW
How many pumping plungers are used in the high pressure pump element used in an inlet metering, opposed plunger, rotary distributor pump used to fuel a six cylinder engine? one four six two
two
Who many pump cylinders are used in a Caterpillar CR system high pressure pump? three one for each engine cylinder one two
two
Plunger to barrel clearances are lapped in manufacture in port-helix metering injection pumps to tolerances between: six and eight microns ten and twelve microns two and four microns one half and one micron
two and four microns
Which of the following is true regarding plunger effective stroke: varies with manifold boost varies with engine rpm it is constant varies with fuel requirement
varies with fuel requirement
What is used to seal fuel in the plunger/pump chamber from the cambox in a typical port-helix metering pump? viscous seal anaerobic seal neoprene seal rubber seal
viscous seal
If theoretically perfect combustion takes place in an engine cylinder using a diesel fuel, what should result from the reaction out the tailpipe? nitrogen and oxygen particulate matter (PM) and carbon hydrocarbons and NOx water and carbon dioxide
water and carbon dioxide
When nozzle back leakage is higher than specification, this is usually an indication of: nozzle seat erosion nozzle valve cavitation wear injector spring fatigue
wear
At what point during effective stroke does the slug of fuel in the pump chamber unite with fuel in the high pressure line? when delivery valve is fully open when retraction piston rises above seat when delivery valve unseats when injector opens
when retraction piston rises above seat
What is a seventh injector used for? Injecting diesel fuel for DPF regeneration Injecting H2O for DPF cooling Injecting diesel fuel for SCR operation Injecting DEF for DPF regeneration
Injecting diesel fuel for DPF regeneration
Which of the following engine OEMs uses a Delphi CR fuel system? Paccar Hino Caterpillar Navistar
Paccar
Technician A says that MY 2013 and later Paccar MX engines use a pair of EUPs to supply the common rail with high pressure fuel. Technician B says that Paccar PX engines use a Bosch CR fuel system. Who is correct? Neither A nor B Technician B only Technician A only Both A and B
Technician A only
Technician A says that a diesel fuel subsystem secondary filter can plug on water causing an engine shutdown. Technician B says that when secondary fuel filter causes an engine shutdown due to fuel starvation, pouring two cans of methyl hydrate into the fuel tank should cure the problem. Who is correct? Technician B only Technician A only Neither A nor B Both A and B
Technician A only
Technician A says that SCR systems use DEF which results in toxic levels of ammonia being emitted from the tailpipe. Technician B says that Navistar engines certified for EPA MY 2013 and later use SCR systems. Who is correct? Technician A only Neither A nor B Technician B only Both A and B
Technician B only
Which of the following would be a typical specific gravity rating of a #2D diesel fuel? 0.825 1.225 0.675 0.557
0.825
What is the specific gravity at 15 degrees Celsius of a diesel fuel with an API gravity of 37 degrees? 0.8137 0.7988 0.7890 0.8398
0.8398
Which of the following acronyms is commonly used to describe the actual ratio of fuel and air in a combustion reaction? RON ASTM SSU AFR
AFR
Which organization is responsible for classifying diesel fuel to a standard? API ATA ASTM SAE
ASTM
Which of the following values is used to measure the heat energy (calorific value) in a fuel? BTU CNG BHP RON
BTU
Technician A says that biodiesel has a short shelf life compared with petroleum sourced diesel fuel. Technician B says that degraded biodiesel can result in costly fuel problems. Who is correct? Technician B only Technician A only Both A and B Neither A nor B
Both A and B
Technician A says that diesel fuel is potentially explosive and should be handled with great care during refilling operations especially in the heat of summer. Technician B says that refueling diesel fuel tanks while smoking a cigarette is not advisable. Who is correct? Technician B only Neither A nor B Technician A only Both A and B
Both A and B
Technician A says that electrohydraulic injectors (EHIs) may use a solenoid actuator. Technician B says that EHIs may use a piezo actuator. Who is correct? Technician B only Technician A only Neither A nor B Both A and B
Both A and B
Technician A says that multi-orifice hydraulic injectors have hard value NOPs. Technician B says that NOPs in electrohydraulic injectors (EHIs) have variable NOPs that are controlled by the ECM. Who is correct? Technician A only Technician B only Both A and B Neither A nor B
Both A and B
Technician A says that multipulse injection can result in smoother engine operation. Technician B says that multipulse injection today can mean breaking up fuel injection into up to 7 events per cycle. Who is correct? Neither A nor B Technician A only Technician B only Both A and B
Both A and B
Technician A says that some diesel post-2007 diesel engines fitted with DPFs use a dosing injector. Technician B says that diesel fuel subsystem charging pressure values can be much higher in engines that use dosing injectors. Who is correct? Neither A nor B Both A and B Technician A only Technician B only
Both A and B
Technician A says that when a diesel fuel tank is vented to atmosphere, more than half the dirt trapped by the fuel filters enters the tank through the breather. Technician B says that a fuel tank breather filter can extend the life of fuel filters. Who is correct? Technician B only Neither A nor B Technician A only Both A and B
Both A and B
Technician A says that diesel fuel in a vehicle tank can degrade when exposed to high temperatures. Technician B says that the most volatile fractions in a diesel fuel are the ones that define the CN of the fuel. Who is correct? Technician B only Both A and B Technician A only Neither A nor B
Both A and B Technician
Which diesel engine manufacturer is noted for the fact that some of their fuel subsystems are entirely under suction? Cummins Mack Trucks Caterpillar Detroit Diesel
Cummins
What should be used to verify the operation of a fuel tank sending unit when it is electrically disconnected? DMM ohmmeter DMM ammeter master gauge dash display diagnostics
DMM ohmmeter
Which of the following is a common toggle option in the software of an electronically managed diesel engine? min-max governing LS or VS governing mechanical or hydraulic governing VS or isochronous governing
LS or VS governing
Technician A says that by delaying refueling of truck diesel fuel tanks until the moment of departure, engine fuel problems can be minimized by ensuring that engines are always using freshest fuel. Technician B says that refueling truck diesel tanks on return from a journey is wasteful as some fuel will boil off from tanks left overnight. Who is correct? Technician A only Neither A nor B Technician B only Both A and B
Neither A nor B
What is used to sense control sleeve position in an EDC managed, VE injection pump? Rheostat Potentiometer Hall effect sensor Engine rpm
Potentiometer
Technician A says that fuel costs are second only to tires when reviewing the operating expenses of trucks on our highways. Technician B says that as fuel costs rise, this provides a competitive advantage to large fleets over individual-owner operators. Who is correct? Technician A only Neither A nor B Both A and B Technician B only
Technician B only
Technician A says that limiting speed (LS) governing is not an option in most electronically controlled engines. Technician B tells a truck driver that he can program his truck to operate in variable speed (VS) governing mode. Who is correct? Technician A only Technician B only Neither A nor B Both A and B
Technician B only
An engine with a reported lack of power (LOP) condition evidently caused by fuel starvation is being diagnosed. The specified maximum inlet restriction on the primary side of the fuel transfer pump is 7-inches HG and the circuit tests at exactly this value. Technician A says that the LOP condition is almost certainly caused by a plugged primary filter and the first step should be to change it. Technician B says that the primary side of the fuel subsystem is not responsible because it still tests within specification. Who is correct? Both A and B Neither A nor B Technician B only Technician A only
Technician A only
Technician A says that a diesel fuel tank plays a role as a heat exchanger in many modern diesel fuel systems. Technician B says that rectangular shaped fuel tanks can provide the same strength using thinner wall thickness than that required for cylindrical tanks. Who is correct? Neither A nor B Technician B only Technician A only Both A and B
Technician A only
Technician A says that secondary fuel filters can entrap particles smaller than the eye can see. Technician B says that primary filters cannot entrap particles smaller than a section of a human hair. Who is correct? Technician A only Technician B only Neither A nor B Both A and B
Technician A only
Technician A says that the pressure in a diesel common rail is equal to that the same as that in an EHI when it is closed in a typical CR fuel system. Technician B says that pressures in a diesel CR fuel system are similar to those in a typical gasoline fuel system. Who is correct? Neither A nor B Both A and B Technician A only Technician B only
Technician A only
When fuel exits a gear pump discharge port while an engine is run, what force moves more fuel into the gear pump inlet in a typical diesel fuel subsystem? atmospheric pressure injection pressure charging pressure gravity
atmospheric pressure
A driver complains that when his truck engine is under load, whenever he removes his foot from the accelerator pedal, engine rpm drops below specified idle speed and occasionally stalls. Which of the following terms is used to describe this condition? underrun droop overrun wide open throttle
underrun
If a truck diesel engine is said to be operating in isochronous mode, which of the following is it most likely doing? running in toque rise using the PTO to pump load running a long downhill gradient climbing uphill
using the PTO to pump load
A hydraulic injector nozzle that uses a sacless design is known as: pencil injector high spring injector low spring injector valve closes orifice (VCO) injector
valve closes orifice (VCO) injector
In conditions of extreme heat in most diesel fuel systems, what happens to diesel fuel vapors boiled off from the fuel in the fuel tanks? charged to a carbon canister exit pick-up tube causing vapor lock create high tank pressures vented to atmosphere
vented to atmosphere
Which of the following terms describes the tendency of a liquid to vaporize? condensivity combustibility viscosity volatility
volatility
When troubleshooting the root cause of a diesel injector in which the tip has been blown off, which of the following should be checked first? API gravity of fuel water-in-fuel condition methyl hydrate in fuel condition lubricity of diesel fuel
water-in-fuel condition
When testing forward leakage on a multi-orifice hydraulic injector nozzle, which of the following is an indication of a good nozzle? minimal leakage at nozzle body drop off leakage is less than 150 psi drop off leakage is less than half NOP zero leakage at nozzle orifices
zero leakage at nozzle orifices
