Deck 12: Heui Injection Systems

Question 1

Pilot injection, also called split-shot injection, in HEUI B injectors is accomplished _______.

A)electronically
B)with a fast-acting single injector solenoid coil
C)with a low-inertia fast-acting dual injector solenoid
D)by mechanically spilling fuel

Answer 1

D

Question 2

Technician A says the measuring unit for the electrical signal to the injection control pressure regulator of a HEUI fuel system is reported as a percentage of duty cycle (%) on a scanner display of engine parameters. Technician B says the PWM signal is reported as time (in milliseconds). Who is correct?

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

Answer 2

A

Question 3

Which of the following components multiplies oil pressure inside a HEUI injector?

A)Injector plunger.
B)Intensifier piston.
C)Poppet valve.
D)PRIME amplifier valve.

Answer 3

B

Question 4

Which of the following conditions is indicated when engine oil contaminates the fuel tank of a vehicle with a HEUI engine?

A)A leaking amplifier piston O-ring.
B)A leaking cylinder head gasket.
C)A defective injection pressure regulator.
D)A leaking injector external O-ring.

Question 5

The maximum potential voltage supplied to a HEUI A or B injector is __________.

A)closest to 12 volts AC
B)closest to 70 volts AC
C)closest to 110 volts DC
D)closest to 70 volts DC

Question 6

While diagnosing the cause of a rough-running 2005 Ford Power Stroke engine, Technician A says that an incorrect injector calibration code will produce uneven cylinder contribution at idle. Technician B says that Gen II HEUI injectors do not use calibration codes. 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 it is important to remove and drain the oil reservoir for a HEUI high-pressure pump when changing engine oil so that the oil does not contaminate the clean engine oil. Technician B says that it is not required or practical to drain the oil reservoir or accumulator when changing oil. Who is correct?

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

Question 8

While discussing the purpose of pilot injection, also known as split-shot injection, Technician A says HEUI injectors use it to reduce NOx emissions. Technician B says PRIME metering can reduce combustion noise. Who is correct?

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

Question 9

Which of the following forces do Gen II HEUI injectors use to physically move the spool valve in the injector control valve mechanism when it opens or closes?

A)Residual magnetism.
B)Oil pressure.
C)Fuel pressure.
D)A PWM signal.

Question 10

Technician A says acoustic wave attenuation (AWA) fittings in the oil manifold of some Gen II HEUI engines reduce irregular combustion noise. Technician B says split-shot injection reduces combustion noise. Who is correct?

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

Question 11

Consider a HEUI fuel system. When the injector pulse width remains constant and the injection control pressure increases, which of the following changes will take place?

A)Injection quantity will be reduced.
B)Injection quantity will be increased.
C)Injection timing will be retarded.
D)Injection timing will be advanced.

Question 12

What change generally takes place when the length of the pulse width to an injection control pressure regulator (ICPR) is increased?

A)Injection pressure increases.
B)Injection pressure decreases.
C)Injection rate is ramped.
D)Injection rate shape becomes squared.

Question 13

What does an above-normal increase in the duty cycle of the PWM signal applied to the HEUI ICPR indicate?

A)Worn-out HEUI injector nozzles.
B)Soot-thickened engine oil.
C)A worn-out high-pressure oil pump.
D)A broken amplifier piston return spring.

Question 14

Technician A says an above-normal increase in the duty cycle of the PWM signal applied to the HEUI ICPR of a Cat C-7 engine indicates that the engine oil has thickened due to excessive soot loading. Technician B says a jumper plug in the wiring harness indicates to the engine's ECM that 10W-30 engine oil rather than 15W-40 oil is being used in the crankcase. Who is correct?

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

Question 15

While considering ways to increase engine power output, Technician A says that using a special injection control pressure (ICP) sensor, which reports oil pressure as lower than the actual pressure, is an effective shortcut. Technician B says that using the modified ICP sensor signal will result in less fuel being injected. Who is correct?

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

Question 16

Consider an engine with a HEUI fuel system. Which of the following problems will most likely cause a hard start/prolonged cranking condition only when the engine is hot?

A)Increased engine oil viscosity.
B)An unusually long PWM signal to the injection pressure regulator.
C)Leaking injector O-rings.
D)The use of antifoaming oil conditioner.

Question 17

What is the measuring unit for the electrical signal to the ICPR of a HEUI fuel system?

A)Percentage of duty cycle (%).
B)Time (msec).
C)Frequency (Hz).
D)Voltage (volts).

Question 18

Technician A says that higher levels of detergents and antifriction additives are needed by HEUI engines to maintain stable injection control oil pressure. Technician B says that antifoaming agents are more important than additional antifriction and detergent additive for a smooth and efficient engine operation. Who is correct?

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

Question 19

While diagnosing the cause of a hard start/prolonged cranking complaint, Technician A says that the high-pressure oil between the high-pressure pump and the injectors should stay pressurized for days. Technician B says the oil pressure to the injectors should quickly drop to zero when the engine is shut off. Who is correct?

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

Question 20

When investigating the cause of frequent injector failures on a HEUI B engine, Technician A says a likely cause could be engine oil contaminated with dirt entering the engine through a leaking air filter. Technician B says that condition will not cause injector failure, because the oil is filtered before supplying the injectors. Who is correct?

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

Question 21

Which diesel injection system is capable of pressurizing fuel independent of engine speed?

A)HEUI (hydraulically actuated electronic unit injection)"
B)Pump-Line-Nozzle rotary injection pump"
C)EUI (Electronic Unit Injection) system
D)MUI (Mechanical Unit Injection) system"

Question 22

Fuel supply pressure is regulated to:

A)10-30 psi"
B)20-50 psi"
C)30-80 psi
D)80-90 psi"

Question 23

The concept of eliminating the camshaft is simple: you use _____ to open and close the valve.

A)hydraulic pressure"
B)mechanical pressure"
C)electronic solenoid
D)spring force"

Question 24

What area of the fueling profiles represent(s) a sharp beginning of injection with a maximum quantity of fuel injected throughout the injection?

A)Square edges"
B)Upward loop"
C)Round edges
D)Downward loop"

Question 25

What injection strategy delivers fuel in two distinct events during one combustion cycle?

A)Pre-injection"
B)Pilot injection"
C)Split-shot injection
D)Main injection"

Question 26

This modular construction feature of HEUI (hydraulically actuated electronic unit injection) system components permits HEUI adaption to a specific engine application by simply changing the:

A)software programming"
B)injection pumps"
C)injectors
D)ECM (engine Control Module)"

Question 27

Which of the following is NOT a variation of the HEUI (hydraulically actuated electronic unit injection) injector?

A)HEUI A"
B)HEUI B"
C)HEUI Gen I
D)HEUI Gen II"

Question 28

Which of the following HEUI (hydraulically actuated electronic unit injection) injectors does not use split-shot- or pilot-injection capabilities?

A)HEUI A"
B)HEUI B"
C)HEUI Gen I
D)HEUI Gen II"

Question 29

What part of the HEUI (hydraulically actuated electronic unit injection) A and B split-shot injector atomizes and distributes fuel into the combustion chamber?

A)High-voltage electric solenoid"
B)Poppet valve"
C)Intensifier piston and plunger
D)Nozzle assembly"

Question 30

During which part of the HEUI (hydraulically actuated electronic unit injection) injector injection cycle does the lower seat of the poppet valve block high-pressure oil from entering the injector?

A)Fill"
B)Injection"
C)End of injection
D)Metering"

Question 31

Which of the following is the ability of the fuel system to adjust the quantity of fuel injected during the injection sequence?

A)Rate control"
B)Ignition delay"
C)Injection delay
D)Pressurization"

Question 32

Which of the following conditions is indicated when engine oil contaminates the fuel tank of a vehicle with a HEUI engine?

A)A leaking amplifier piston O-ring."
B)A leaking cylinder head gasket."
C)A defective injection pressure regulator.
D)A leaking injector external O-ring."

Question 33

What is unique about the digital valve in the Gen II injector is its dependence on _____ to move the control valve.

A)magnetic induction"
B)the spinning generator"
C)PWM (Pulse Width Modulation)
D)residual magnetism"

Question 34

Which part of the Gen II injector event begins with the spool valve in the closed position, preventing oil from entering the injector?

A)Pre-fill"
B)Fill"
C)Main injection
D)End of injection"

Question 35

Which part of the Gen II injector event energizes the open coil, moving the spool valve to the open position?

A)Pre-fill"
B)Fill"
C)Main injection
D)End of injection"

Question 36

Which of the following minimizes a rhythmic cackling noise at idle caused by pressure waves from the high-pressure pump synchronizing with injection events?

A)Dampener"
B)Pressure control valve"
C)Acoustic Wave Attenuation (AWA)
D)Snubber valve"

Question 37

Technician B says that Gen II injection timing can be varied by changing the specific time during crankshaft rotation to cycle the open and close coils. Technician B says to change the rate of fuel delivery, the oil pressure to the injector is electronically varied by a variable resistor. Who is right?

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

Question 38

Technician A says acoustic wave attenuation (AWA) fittings in the oil manifold of some Gen II HEUI engines reduce irregular combustion noise. Technician B says split-shot injection reduces combustion noise. Who is correct?

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

Question 39

Which of the following is a unique feature of the HEUI HIB-300 injector?

A)Electronically balanced poppet valve"
B)Hydraulically balanced nozzle valve."
C)Low-mass poppet valve
D)High-mass poppet valve"

Question 40

What is used in the wiring harness to indicate to the ECM the viscosity of oil used?

A)Removable plug"
B)Removable resister"
C)Variable resistor
D)Capacitor circuit"

Question 41

Pilot, main, and post-combustion injection events in the HEUI HIB-300 injector are controlled by the electrical signals to the:

A)spool valve"
B)poppet valve"
C)solenoid
D)intensifier"

Question 42

When the spool valve opens, high-pressure oil is directed to the top of the _____ and then injection begins.

A)amplifier piston"
B)solenoid"
C)intensifier
D)poppet valve"

Question 43

Two technicians are describing HEUI HIB-300 injector operation. Technician A says that lifting the poppet valve opens a passageway, allowing pressurized oil above the nozzle valve to drain to a low-pressure oil return. Technician B says that a spool valve moves from side to side controlled only by magnetic forces. Who is right?

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

Question 44

Two technicians are describing HEUI HIB-300 injector operation. Technician A says that fuel travels to the cavity above the amplifier piston while pressurized oil is applied to two sides of the poppet valve and to the top of the nozzle valve, holding it closed. Technician B says that when the poppet valve is energized, the valve lifts, closing off the high-pressure oil passageway and applying pressure to the nozzle valve. Who is right?

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

Question 45

Which HEUI oil circuit does not pass through a filter, but instead connects the engine's main oil gallery to the reservoir?

A)High pressure supply"
B)Low pressure supply"
C)Short-circuit supply
D)Oil reservoir"

Question 46

What prevents oil from draining back to the crankcase when the engine is not operated?

A)Oil filter"
B)Injectors"
C)Spool valve
D)One-way check ball"

Question 47

Later designs of HEUI (hydraulically actuated electronic unit injection) systems corrected the problem of short-circuit oil supply by using oil filtered by the engine to supply the:

A)high-pressure circuit"
B)low-pressure circuit"
C)oil pan
D)oil pump"

Question 48

Reservoirs with a capacity of approximately ________ are incorporated into high-pressure pumps or cavities in the engine.

A)0.26 gallon"
B)0.50 gallon"
C)1 gallon
D)2 gallons"

Question 49

Technician A says that during an oil change, oil can be drained from the accumulator or reservoir of a HEUI (hydraulically actuated electronic unit injection) system. Technician B says that reservoirs with a capacity of approximately 0.26 gallon (1 liter) are incorporated into high-pressure pumps or cavities in the HEUI engine. Who is right?

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

Question 50

Which device uses an electrically operated spool valve that moves in response to the strength of a magnetic field to control injector oil pressure?

A)High-efficiency pump (HEP)"
B)Injection control pressure regulator (ICPR)"
C)Injection control pressure (ICP) sensor
D)Oil pressure regulator"

Question 51

What level of voltage do Gen II injectors require?

A)148 volts and 20 amps"
B)75 volts and 30 amps"
C)48 volts and 20 amps
D)115 volts and 8 amps"

Question 52

What level of voltage do HEUI (hydraulically actuated electronic unit injection) A and B injectors require?

A)115 volts and 8 amps"
B)148 volts and 20 amps"
C)75 volts and 30 amps
D)48 volts and 20 amps"

Question 53

Current used to energize the injectors is stored in:

A)TRC circuits"
B)RC circuits"
C)ECM (Electronic Control Module)
D)capacitors"

Question 54

Which module stores information such as engine firing order and operating and diagnostic software instructions?

A)ECM (Electronic Control Module)"
B)CCM (Computer Control Module)"
C)FICM (Fuel Injection Control Module)
D)ICM (Injection Control Module)"

Question 55

Two control signals from the ECM are supplied to the FICM (fuel injection control module): the fuel-delivery control signal (FDCS) and the:

A)cylinder identification (CID) signal"
B)engine position (CKP) signal"
C)camshaft position (CMP) signal
D)engine coolant temperature (ECT) signal"

Question 56

While diagnosing the cause of a hard start/prolonged cranking complaint, Technician A says that the high-pressure oil between the high-pressure pump and the injectors should stay pressurized for days. Technician B says the oil pressure to the injectors should quickly drop to zero when the engine is shut off. Who is correct?

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

Question 57

When replacing a HEUI (hydraulically actuated electronically controlled unit injector) injector, you inspect the condition of the inlet injector O-rings and find it nicked. Which of the following actions do you take?

A)Replace the O-ring"
B)Rebuild the injector"
C)Replace the injector
D)Replace all injectors"

Question 58

Caterpillar uses a removable electrical jumper plug on C-7 and C-9 engines to correct actuation system variables when using either:

A)15W-40 or 10W-40 engine oil"
B)5W-40 or 10W-40 engine oil"
C)15W or 40W engine oil
D)10W-40 or 20W-40 engine oil"

Question 59

Oil thickened by excessive soot loading will interfere with injector control valves operating properly, particularly in:

A)hot weather"
B)idle when hot"
C)cold weather
D)part-throttle"

Question 60

If Gen II injectors misfire, fail to deliver the correct quantity of fuel, are worn out or contaminated, or have sticking control valves, then they may need to be:

A)replaced"
B)rebuilt"
C)sent to a fuel shop
D)adjusted"