CM850 Electronic Control System – 019-396   Fuel Lift Pump

Initial Check

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With EGR


NOTE: This test only applies to engines equipped with EGR. Engines not equipped with EGR do not have a lift pump.

NOTE: High fuel inlet restriction can result in lift pump damage. Before replacing the lift pump, measure the fuel inlet restriction. Refer to Procedure 006-020, in the Troubleshooting and Repair Manual, ISBe, ISB and QSB5.9 (Common Rail Fuel System) Series Engines, Bulletin 4021271.

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If service tool, Part Number 316461, lift pump performance test orifice, is not available, the following instructions can be followed to assemble the tool.

Tap a female quick connect, Part Number 3376859.

Tap size: 8-36 national fine (U.S.)

 
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 WARNING 

Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

Clean the female quick connect, Part Number 3376859, with compressed air to remove debris.

Assemble a 1.09-mm [0.043-in] injector orifice, Part Number 3045018, with washer, to the female quick connect, Part Number 3376859.

NOTE: To obtain correct flow, use a 1.09-mm [0.043-in] injector orifice, Part Number 3045018.

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Attach to an appropriate length (it must reach from the lift pump to the measurement device) of 1/4-inch, or larger, tubing.

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Install an M10 male Compuchek™ fitting, Part Number 3824842, on the diagnostic port on the inlet side of the fuel filter. Connect the service tool containing a 1.09-mm [0.043-inch] orifice, Part Number 3164621, to the diagnostic port.

Allow the other end of the hose to drain into a 500-ml graduated beaker, Part Number 3823705.

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NOTE: This test is performed with the engine not running.

Start the lift pump by using the INSITE™ electronic service tool, lift pump override test. Refer to INSITE™ electronic service tool. Alternatively, the lift pump can be temporarily activated by “bumping” the starter without starting the engine or by turning the keyswitch on.

Measure the amount of fuel flowed by the lift pump in a 60-second interval:

  • Fuel flow rate for lift pump (engine not running) –
    greater than 600 ml in 60 seconds or filling a 12-ounce can in 36 seconds or less.

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NOTE: Voltage will only be present when the lift pump is commanded ON. This can be accomplished by either using the INSITE™ electronic service tool lift pump override test or by “bumping” the starter.

If the lift pump is not functioning properly, check the voltage and resistance at the lift pump.

If the voltage does not meet the specifications, check the power supply.

System Voltage Resistance
12 VDC 9 VDC (minimum) 5 ohms (maximum)
24 VDC 21 VDC (minimum) 5 ohms (maximum)

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Clean

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With EGR


Thoroughly clean the fittings and components before removal. Make sure that debris, water, steam, or cleaning solution does not reach inside the fuel system.

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Remove

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With EGR


 WARNING 

Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

Disconnect the battery.

 
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Remove the fuel lift pump inlet and outlet fuel lines.

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Remove the fastener holding the lift pump to the back of the ECM cooler plate.

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Install

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With EGR


NOTE: Make sure the inlet and outlet are properly oriented. Check the lift pump for labeling of inlet and outlet ports. Verify that the correct pump
(12 VDC or 24 VDC) is installed.

Install the lift pump on the mounting bracket behind the ECM cooling plate.

Torque Value:  7  n.m  [62 in-lb]

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Install the fuel lift pump inlet and outlet fuel lines.

Torque Value:  24  n.m  [212 in-lb]

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 WARNING 

Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

Connect the battery.

 
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Prime

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 WARNING 

The fuel pump high-pressure fuel lines and fuel rail contain very high-pressure fuel. Never loosen any fittings while the engine is running. Personal injury and property damage can result.

It is not necessary to vent air from the high-pressure fuel system before starting the engine. Cranking the engine will prime the fuel system.

For engines with EGR, allow the lift pump to run by turning the keyswitch ON and waiting 30 seconds before starting.

 
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Last Modified:  17-Mar-2005