Deck 29: Cummins Hpi-Tp

Question 1

What does the T represent in the Cummins acronym HPI-TP?

A) tolerance
B) time
C) test
D) transfer

Answer 1

time

Question 2

Which of the following is true of the camshafts used in a pre-2010 Cummins ISX engine?

A) twin overhead with identical functions
B) twin overhead with separate functions
C) double block-mounted
D) chain driven

Answer 2

twin overhead with separate functions

Question 3

Technician A says that Cummins ISX, HPI-TP injectors are mechanically actuated with no integrated electronic components. Technician B says that injection timing in an HPI-TP injector is variable and managed by the engine ECM. Who is correct?

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

Answer 3

Both A and B

Question 4

Which of the following specifications describes the peak injection pressure capability of an HPI-TP injector?

A) less than 15,000 psi (1000 bar)
B) 21,000 psi (1450 bar)
C) 25,000 psi (1700 bar)
D) more than 30,000 psi (2000 bar)

Question 5

How many ECM actuators are located on the rail of a Cummins ISX engine using HPI-TP fuel management?

A) two
B) three
C) four
D) six

Question 6

Technician A says that in an ISX engine using HPI-TP injectors, one metering actuator is responsible for fueling the front three cylinders and another for the rear three. Technician B says that on the same engine, one timing actuator manages timing on cylinders #2 and #5. Who is correct?

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

Question 7

Where would you find a GoreTex seal on a Cummins ISX engine?

A) rail
B) HPI-TP injector
C) timing actuator
D) ECM

Question 8

Technician A says that a pre-2010 ISX engine uses concept gears in the timing gear train. Technician B says that the ISX engine uses a single slab cylinder head. Who is correct?

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

Question 9

Technician A says that the HPI-TP injector uses open-nozzle technology. Technician B says that an HPI-TP injector will have a variable beginning and hard value, constant ending to its injection cycle. Who is correct?

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

Question 10

What is the approximate rail pressure used in a Cummins HPI-TP fuel management system?

A) over 30,000 psi (2000 bar)
B) around 25,000 psi (1700 bar)
C) 5,000 psi (345 bar)
D) 285 psi (19.7 bar)

Question 11

At the completion of the Cummins HPI-TP injector pumping stroke, where is the fuel in the timing chamber routed?

A) engine cylinder
B) drain circuit to IFSM
C) directly to fuel tank
D) spilled to rocker housing

Question 12

When comparing the operation of HPI-TP injectors with electronic unit injectors (EUIs) using hydraulic injector nozzles, which of the following is a major advantage of the HPI-TP injector in dealing with emissions?

A) higher peak pressures
B) no integral electronic components
C) elimination of end of injection collapse phase
D) lower nozzle opening pressure

Question 13

Which of the following will determine how much fuel is injected by a Cummins HPI-TP injector in any given cycle?

A) duration (time) the metering actuator is energized
B) fuel quantity in the timing chamber
C) length of the metering plunger stroke
D) common rail pressure

Question 14

When does Cummins the HPI-TP injector mechanical stroke that results in injecting fuel take place?

A) only when fuel is in the timing chamber
B) cam ramp-down from OBC to IBC
C) cam ramp-up from IBC to OBC
D) only when fuel is in the metering chamber

Question 15

How much fuel should remain in the HPI-TP injector timing chamber at the completion of an injection cycle?

A) none
B) minimal quantity
C) enough to provide hydraulic lock
D) full charge

Question 16

What must be used to time the camshafts in a Cummins ISX engine?

A) dial indicator
B) thickness gauges
C) OEM calibration indices
D) OEM timing wedges

Question 17

Where does the post-2007 ISX hydrocarbon injector used to dose the DPF receive its fuel from?

A) IFSM rail
B) fuel charging circuit
C) secondary filter
D) directly from fuel tank

Question 18

Where are the electronics that manage the timing and metering actuators housed?

A) IFSM
B) ECM
C) InSite module
D) vehicle bulkhead

Question 19

Cummins Intebrake operation is being discussed. Technician A says that three solenoids are used to manage six progressive levels of braking. Technician B says that when solenoid #1 is energized, engine braking is effected on #1 engine cylinder only. Who is correct?

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

Question 20

What must be used to troubleshoot the Cummins ISX, HPI-TP fuel system?

A) OEM service literature
B) INSITE software
C) CELECT Plus software
D) a digital multimeter (DMM)

Question 21

In the Cummins HPI-TP fuel system, what is the control variable in the hydraulic equation used to determine injected fuel quantity?

A) time
B) pressure
C) flow area
D) accelerator angle

Question 22

Technician A says that the fuel filter used in the Cummins HPI-TP fuel system can either be under pressure or suction, depending on when the engine was manufactured. Technician B says that fuel movement through the fuel subsystem in an ISX engine is created by a gear type fuel transfer pump. Who is correct?

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

Question 23

Where is the fuel transfer gear pump located in a Cummins HPI-TP fuel sub-system?

A) engine accessory drive
B) integrated fuel system module (IFSM)
C) ECM housing
D) fuel tank

Question 24

Which pair of actuators are located outboard on the IFSM on an HPI-TP fuel system?

A) one metering, one timing
B) the timing actuators
C) the metering actuators
D) the injector actuators

Question 25

What is the specified rail pressure in an HPI-TP fuel system?

A) 150 psi (10.4 bar)
B) 285 psi (19.7 bar)
C) 320 psi (22 bar)
D) over 30,000 psi (2000 bar)

Question 26

What type of signal is used to control Cummins HPI-TP timing and fueling actuators?

A) pulse width modulated (PWM)
B) spiked DC
C) data bus
D) AC

Question 27

Technician A says that all fuel injected into the engine cylinders in an HPI-TP fuel system must first pass through one of two timing actuators. Technician B says that there are a total of four rail actuators on an HPI-TP fuel system. Who is correct?

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

Question 28

Technician A says that both the timing and metering actuators are exposed to identical rail fuel pressure at any given moment of operation. Technician B says that one timing actuator manages fuel delivered to the injector timing chambers in the injectors fueling cylinders 1, 5 and 3. Who is correct?

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

Question 29

Which of the following correctly describes the cylinder head(s) used on a pre-2010 ISX HPI-TP fueled engine?

A) single slab
B) one per cylinder
C) two over 6 cylinders
D) three over 6 cylinders

Question 30

Which of the following correctly describes the role of the fuel delivered to the HPI-TP injector by the timing actuator?

A) fuels engine
B) partially fuels engine
C) forms a hydraulic lock to actuate pumping plunger
D) gets returned to the rail after effective stroke

Question 31

Technician A says that the amount of fuel metered to the HPI-TP metering chamber depends on ECM managed rail pressure at any given moment of operation. Technician B says that all of the fuel injected into the engine cylinder by an HPI-TP injector must pass through the metering actuator. Who is correct?

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

Question 32

What is used on an HPI-TP injector to prevent back-pressurizing of the fuel rail by the metering chamber when the injector is first actuated (pre-injection) by the camshaft?

A) fueling check valve
B) timing check valve
C) fueling orifice
D) timing orifice

Question 33

When the HPI-TP timing chamber has the most amount of fuel charged to it, which of the following should be true?

A) the least amount of fuel is injected
B) the most amount of fuel is injected
C) injection timing is at its most advanced
D) injection timing is at its most retarded

Question 34

At the end of an HPI-TP injection cycle, which of the following is true?

A) nozzle spring closes fueling plunger
B) HPI-TP tappet spring closes cup orifice
C) moving components of the injector are loaded into the cup with mechanical crush
D) the cup orifice remain "open" and exposed to cylinder gas pressure

Question 35

Which of the following features gave the HPI-TP injected engine a major advantage in controlling emissions when compared to an engine fueled by EUIs equipped with hydraulic nozzles?

A) cooler engine operation
B) collapse phase at end of injection is eliminated
C) fueling is not limited by a hard cam lift window
D) integral control solenoid is eliminated