Engine test 4
What could cause white smoke to come out of the exhaust on a diesel engine on start up and while cranking?
Low compression
Fuel pressure too high
Boost pressure too high
Boost pressure too low
What type of code would be generated if an oil pressure sensor was disconnected with engine running?
Active
Inactive
Logged
Shutdown
How is an active code cleared
Clearing all codes with the diagnostic reader
Moving it to the inactive code list with a laptop computer then clearing it
Disconnecting the Electronic Control Module (ECM) power source
Repairing the cause of the code then clearing it
What is the problem if the needle on an electric temperature gauge will only move when the wire to the sender is grounded?
The sender is faulty
The wire has an open
The gauge is faulty
There is no power to the gauge
In vehicle electronic control module (ECM) which type of the memory can be reprogrammed electronically by a laptop
Random access memory (RAM)
Electrically erasable programmable read only memory (EEPROM)
Non-Volatile random access memory (NV-RAM)
Programmable read only memory (PROM)
Which of the following statements is true
Random access memory (RAM) is volatile
Read only memory (ROM) is reprogrammable
Programmable read only memory (PROM) data is rewritable
Erasable programmable read only memory (EPROM) is reprogrammable while in the vehicle
Which type of memory would be retained when the ignition key is turned off, but is lost when the battery is disconnected
Read only memory (ROM)
Non-volatile random-access memory (NV-RAM)
Random access memory (RAM)
Electrically erasable programmable read only memory (EEPROM)
What is the definition of a "Full Authority" electronic diesel engine
Electronically controlled mechanical unit injector
Electronic governing with hydraulically controlled timing advance
Electronically controlled fuel metering with mechanical governor
Electronically controlled fuel metering and injection timing
What is the reference voltage sent to most sensors?
0.25 to 4.75 volts
4.5 to 5.5 Volts
8 + 0.5 volts
System Voltage
What is the term used to describe the amount of time an electronically controlled injector solenoid is energized
Duty control
Pulse width
Timing reference
Applied duration
Which of the following best describes the characteristics of an NTC type thermistor sensor
Resistance decreases as temperature increases
Voltage drop over the sensor is constant at all temperatures
Resistance increases as temperature increases
Sensor opens when a specific temperature is reached
Which of the following devices does not require a reference voltage input
Induction pulse generator
Potentiometer
Variable capacitance sensor
Thermistor
With the exception of caterpillar, which of the following is not true of the signal voltage value returning to the electronic control module (ECM) from a properly functioning throttle position sensor (TPS)
Varies proportionally with pedal travel
Zero volts when the pedal released
Converted to digital signal at the ECM
Must be less than reference voltage
If a large number of fault codes reappear after they have been cleared and the engine has run only a short time, what could be the cause
Shorts in the sensor wiring
Poor electronic control module (ECM) ground
Faulty throttle position sensor (TPS)
A diagnostic reader malfunction
What would happen to the signal voltage sent to the electronic control module (ECM) if an open occured in a two-wire speed sensor
Drops to a value above 0.0 volts but below 0.25 volts
Higher voltage between 4.75 volts and 4.99 volts
Full reference voltage returned
No voltage signal
What is the first thing that a technician should do before welding on an electronically equipped engine
Disconnect the battery and unplug all electronic control module (ECM) harnesses
Attach the welding ground clamp as close to the work as possible
Disconnect the electronic control module (ECM) power input
Unplug all harnesses
What voltage does the electronic control module (ECM) read when a three-wire sensor has an open in the ground wire
Low voltage
High Voltage
No voltage
No change in voltage
Why should caution be exercised when working around a running electronic unit injector (EUI) engine
Hydraulic injector drive trains move with great force
Solenoid voltage can be 100 volts or more
Engine oil is thrown around by the valve train components
Fuel at injection pressures can penetrate through clothing
What type of code would be generated if a sensor was disconnected with the engine running
Logged
Active
Inactive
Shutdown
What should be done before removing an electronic unit pump (EUP) from an engine cylinder block
Drain the fuel manifold
Drain the engine oil
Remove the camshaft
Cage the EUP retraction spring
What happens when the injector solenoid on a detroit diesel electronic control (DDEC) electronic unit injector engine is energized
Injector plunger starts to travel downward
Poppet valve opens the spill passage
Poppet valve closes the spill passage
Pressurized fuel lifts the nozzle valve
What force is used to develop injection pressures in the detroit diesel electronic control (DDEC) electronic unit injector (EUI)
Hydraulic from the high pressure oil pump
Mechanical from injector cam profile
Electrical from the injector solenoids
Electronic from control cartidges
When performing a cylinder cut-out test on a detroit diesel electronic control (DDEC) electronic unit injector (EUI) fuel system, what result would indicate the faulty cylinder is being cancelled?
Average pulse width of the other injectors does not change
Average pulse width of the other injectors increases
Average pulse width of the other injectors decreases
Engine speed drops
What will happen if the synchronous reference sensor (SRS) fails on a detroit diesel electronic control (DDEC) engine while it is running
The check engine light (CEL) will illuminate then the engine will ramp down
The engine will stop immediately due to loss of the timing signal
The stop engine light (SEL) will illuminate then the engine will shut down
The engine will continue to run normally but will not start again
What happens to a shutdown a caterpillar electronic unit injector (EUI) engine
Fuel flow to the injectors is stopped
Injector solenoids are not energized
Throttle position sensor (TPS) moves to a no fuel position
Signal from the speed/timing sensor is interrupted
Which of the following determines the effective stroke of the plunger in the caterpillar electronic unit injector (EUI)
Fuel volume entering the plunger chamber
Time the EUI solenoid is energized
Initial height setting of the EUI
Cam lift
A six-cylinder caterpillar engine with an electronic unit injector (EUI) fuel system is being checked for a faulty cylinder. How many cylinders are firing during the testing phase using the preferred method
1
2
4
5
After replacing an injector on a caterpillar electronic unit injector (EUI) fuel system what procedure must be done before starting the engine
Clear all fault codes from the ECM
Adjust the intake and exhaust valves
Disconnect then reconnect the ECM power harness
Log the new injector code in the ECM
What is the fuel pump outlet pressure for a cumming N14 Celect engine
5 to 150 psi
60 to 80 PSI
145 to 155 psi
depends on engine speed
What happens in the cummins celect injector to end injection
The injector solenoid is de-energized
The timing spill port is uncovered
The metering spill port is uncovered
The injector plunger starts to move upward in its bore
Which of the following describes the role of fuel that enters the timing chamber in a cummins celect injector
Keeps the spill passages sealed
Provides a hydraulic link between the timing and metering plungers
Keeps the metering check ball seated
Prevents further metering of fuel into the pumping chamber
Where is the engine position sensor located on a cummins n14 celect engine
In the bell housing close to the (NOT THIS ANSWER
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What is the procedure to install the actuators on a high-pressure injection time pressure (HPI-TP) integrated fuel systems module (IFSM)
Scrape off the old gasket clean the surface and install the new actuator
Always replace the IFSM as a unit
clean the mating surfaces install new o-rings seals, lubricate, and install the new actuator
Apply gasket eliminator to the sealing surfaces and install the new actuator
What controls pressure available at the timing and metering actuators on the high-pressure injection-time pressure (HPI-TP) fuel system
The system relief passage, internal drilling
The high pressure relief valve
The timing/ metering pressure relief orifice
The regulator valve
What could happen with the high-pressure injection-time pressure (HPI-TP) fuel system if the electronic control module (ECM) fuel cooling plate develops a leak from corrosion
The ECM will over heat causing extensive electrical damage to the electronic control module
Suction at the pump inlet could allow air into the fuel system
The ECM mounting plate will leak fuel into the ECM causing electrical malfunction
The regulator will allow the fuel to bypass the ECM cooler
How is injection timing accomplished with the high-pressure injection-time pressure (HPI-TP) fuel injection system
The metering actuator will fill the injector cup, which will determine the injection timing
The electronic control module (ECM) will close the poppet valve at the precise moment to being injection
The metering actuator determines the quantity and timing of fuel injection
Fuel from the timing actuator is used as a hydraulic link in the injector to control injection timing
What causes the timing plunger to separate from the upper plunger in the high-pressure injection-time pressure (HPI-TP) fuel system
Fuel pressure from the metering actuator
Upward momentum of the rocker shaft
The timing spring in the timing chamber of the HPI-TP injector
Fuel pressure from the timing actuator
What would cause incorrect actuation oil pressure with the hydraulic electronic unit injector (HEUI) fuel system
High operating temperatures above +40 C
Low fuel level
Cold operating temperatures below -20 C
Shorted injector pressure regualtor solenoid
What type of pump is used in the hydraulic electronic unit injector (HEUI) fuel system to raise the engine oil pressure to actuation pressures
External gear
Vane
Plunger
Piston
In the hydraulic electronic unit injector (HEUI) fuel system what does the injection pressure regulator (IPR) valve control
Length of the injector plunger effective stroke
Actuation oil pressure
Fuel injection pressure
Duty cycle of the injector solenoid
When actuation oil enters the hydraulic electronic unit injector (HEUI) which of the following components does it act directly on
Fuel pressure regulator
Pumping Plunger
Amplifier Piston
Nozzle Valve
What event ends the effective pumping stroke of the hydraulic electronic unit injector (HEUI)
Energizing the HEUI solenoid
Metering piston spill port exposed
Injection nozzle closing
De-energizing the HEUI solenoid
What determines how fast the hydraulic electronic unit injector (HEUI) amplifier piston is driven through its stroke
Actuation oil pressure
Length of time the HEUI solenoid is energized
Engine RPM
Poppet spill flow area
Which of the following conditions would have the greatest influence on the performance of the hydraulic electronic unit injector (HEUI) fuel system
Extending the service intervals for fuel filter change
Aerated engine oil
Incorrectly adjusted injector static timing
Using winter fuel in summer months
What would cause over-fueling of injectors in a high pressure common rail (HPCR) fuel system
Incorrect injector height adjustment
Rai pressure regulator malfunction
Contaminated fuel supply to the injectors
Rail pressure too high
What is used to trigger the injection nozzle used in common rail injection (CRI) fuel systems
Electrical pulse
Mechanically actuated lever
Engine oil pressure
Pressure spikes from the accumulator
What is used to generate fuel injection pressures in common rail injection (CRI) fuel systems
Engine gear train driven piston pumps
High pressure oil amplification pumps
Valve camshaft lobe driven piston pumps
Electronically controlled solenoid pumps
In most common rail injection (CRI) fuel systems what would happen if an injection nozzle stuck open
Fuel rail pressure would collapse
Cylinder would fill with fuel
Immediate engine shutdown
Damage to that cylinder and piston
If theoretically perfect combustion takes place using diesel fuel, what would be the resulting emissions
Water and oxygen
Nitrogen and oxygen
Hydrocarbons and NOx
Water and carbon dioxide
What emission increases when ignition timing is retarded in a diesel engine
Carbon dioxide
Particulate matter
Oxides of sulphur
Oxides of nitrogen
What is the first step to take when troubleshooting diesel particulate filter (DPF) problems
Check engine performance with the DPF bypassed
Take temperature readings during active regeneration
Hook up the service tool and check for fault codes
Inspect the condition of the filtering element
Which of the following devices or systems has been proven to lower NOx emissions in the exhaust of highway diesel engines
Particulate trap
Exhaust gas recirculation
Diesel particulate filter
DPF
If a diesel engine is run without a thermostat which emission would increase
Sulphur dioxide
oxides of nitrogen
Carbon dioxide
Hydrocarbons
What exhuast emissions would increase if an air-to-air cooler was externally onbstructed
Carbon monoxide
Sulphur dioxide
Carbon dioxide
Oxides of nitrogen
Which emission increases when ignition timing is advanced in a diesel engine
Particulate matter
Carbon dioxide
Oxides of sulphur
Oxides of nitrogen
What is the purpose of urea in the selective catalyic reduction (SCR) system
To convert NOx into NH3 and diesel exhaust fuel (DEF) which is sprayed into the exhaust stream
To reduce NOx in to N2 and H20
To reduce NOx to N2 and O2
To give the exhuast an ammonia smell
What is the primary function of the diesel oxidation catalyst (DOC)
Convert fuel to heat and N2 to NO2
Convert fuel to heat and HC to n2
Convert fuel to heat and soot to ash
Convert fuel to heat and NO TO NO2
Over time ash gets collected in the diesel particulate filter (DPF) Where does this ash come from
Coolant additives
Oil additives
Fuel additives
The regeneration process
What would cause melting of the diesel particulate filter (DPF)
Faulty after-treatment hydrocarbon injector
Face plugging of the diesel oxidation catalyst (DOC)
Sustained high temperatures above 1200 F (650 C)
Excessive engine coolant in the exhaust stream
What will signal the operator of the need for a stationary regeneration
Red engine lamp on
Red engine lamp flashing
Diesel particulate filter (DPF) lamp flashing amber then red
Amber light flashing
What will cause a diesel particulate filter (DPF) missing related fault code
Resistance is below a threshold for a calibrated period of time
If the calculated exhaust flow is greater with more engine load
if the calculated exhaust flow is lower with less engine load
if the differential pressure sensor reads a difference in pressures
What sensor input is used by the electronic control module (ECM) to determine the amount of particulates in the diesel particulate filter (DPF)
Exhaust gas recirculation (EGR) differential pressure sensor
Exhaust back pressure sensor
DPF back pressure sensor
DPF differential pressure sensor
What is injected into the exhaust of a selective catalyic reduction (SCR) equipped engine during the reduction stage and what is the result
Urea is injected and broken down to ammonia to reduce the NOx to N2 and H2O
diesel exhaust fuel (DEF) is injected into the exhaust to clean the filters
Ammonia is injected into the exhaust stream
Diesel fuel is injected to reduce the oxides of nitrogen NOx
What is the function of the intake throttle on some of the newer diesel engines
Assisting exhaust gas circulation (EGR) flow when boost pressure is higher than exhaust pressure
Operating the pneumatic governor
Extra air when the power demand is high
Introducing more fuel when the power demand is high
What is the primary function of a crankcase breather filter
To collect all the particulates from the blow-by gases
To enhance the performance of the engine
To purify and recycle the engine oil
It is just another added cost to the costumer
Why is it important to remove all trapped air from the cooling system
To prevent exhaust gas recirculation (EGR) mixer failure
To prevent damage to the coolant temperature sensor
To prevent engine overheating and high particulates
To prevent exhaust gas recirculation (EGR) cooler failure
What is the primary function of the diesel particulate filter (DPF)
Collect particulate matter
Convert soot from fuel to CO2 and n2
Convert soot from oil to C02 and N2
reduce fuel consumption
What sensor is used to measure the flow of exhaust gases into the air intake of a diesel engine
Exhaust gas recirculation (EGR) differential pressure sensor
Exhaust gas recirculation (EGR) temperature sensor
Turbo nozzle position sensor
Exhaust pressure sensor
How should compressed natural gas (CNG) always be stored
In a liquid state to reduce harmful emissions
Properly to prevent the release of high pressure posionous gas
Compressed and odorized to the appropriate level
In a suitable cryogenic fuel tank
What is the octane rating of liquid petroleum gas (LPG)
The same as diesel fuel
LPG does not have an octane rating
115
The same as the cetane rating
What is the octane rating of compressed natural gas (CNG)
The same as diesel fuel (WRONG)
CNG does not have an octane rating (WRONG)
Could possibly be right
Could possibly be right
Not on quiz
ANSWER
ANSWER
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What usually causes freeze-up of the propane converter during normal operation
Lack of coolant circulation
Strainer restriction
Too much coolant circulation
Incorrectly set withdrawl valve
In what state is the fuel stored in a compressed natural gas (CNG) system
Gas
Liquid
Solid
Gas and liquid
To be effective the engine compression brake must do what near the top dead centre (TDC) compression stroke
Open the exhaust valve
Open both valves
Open the intake valve
Inject fuel
What is the braking effectiveness of an engine brake at its highest
At idle rpm
At peak engine RPM
At maximum wheel speed
Anywhere during the torque rise
When is a compression engine brake usually adjusted
With the engine stopped and in the correct position
At idle speed with the brake on
With the engine stopped and in any position
At idle speed with the brake off
On a class 8 highway truck which switch does not have to be closed in order for a typical engine compression brake to operate
Clutch engaged switch
Fuel pedal switch
Service brake pressure switch
Driver control switch
What would cause a compression brake to continue to operate on only one cylinder after the master switch is turned off
A broken or collapsed control valve spring
Wrong clearance setting at the exhaust valves
Solenoid is still energized
A ball check valve is leaking
What would be checked first if the engine hydraulic retarder worked normally but the engine overheated soon after engaging it
Temperature of the coolant in and out of the engine oil cooler
Retarder control valve operation
Engine radiator for external restriction
Operating temperature of the transmission
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