Home » ISX11.9 CM2250 - Service Manual » Cummins ISX11.9 CM2250 – Service Manual 005-234   Fuel System Priming

Cummins ISX11.9 CM2250 – Service Manual 005-234   Fuel System Priming

General Information

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If the engine has been allowed to run out of fuel or the fuel system has been serviced or repaired, it will be necessary to prime the fuel system.

Use the appropriate section below.

 
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Prime

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With Fuel Lift Pump


NOTE: Engines equipped with priming pumps do not require the fuel filter to be filled prior to installation, if the following filling procedure is followed.

 
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 WARNING 

When servicing the engine do not rotate the crankshaft with a high-pressure fuel system joint open. Rotating the crankshaft can create highly pressurized fuel in the fuel system.  High-pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

NOTE: The engine can possibly run rough for several minutes until the air is out of the system.

Do not vent the fuel system from a high-pressure fuel system joint.

To assist in fuel system priming and removing air from the fuel system, an orificed diagnostic fuel line, Part Number 3164621, may be used to bleed air from the low-pressure fuel system.

Install the orificed diagnostic fuel line to the Compuchek™ fitting at the inlet to the pressure side fuel filter (outlet to the fuel pump gear pump). Turn the key to the ON position. Do NOT start the engine. Allow the priming pump to run and observe the orificed diagnostic fuel line. When a solid stream of fuel exits the line the initial priming process is complete. It may be necessary to repeat this process two or three times.

Remove the diagnostic fuel line

 
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 WARNING 

When servicing the engine do not rotate the crankshaft with a high-pressure fuel system joint open. Rotating the crankshaft can create highly pressurized fuel in the fuel system.  High-pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

NOTE: The engine can possibly run rough for several minutes until the air is out of the system.

Start the engine and allow it to stabilize. Attach the diagnostic fuel line to the Compuchek™ fitting at the inlet to the pressure side fuel filter (outlet to the fuel pump gear pump). Shut off the engine and observe the orificed diagnostic fuel line. Allow the entrapped air to expand and exit through the diagnostic fuel line.

Repeat this process up to four times or until air no longer exits the diagnostic fuel line. If air continues to exit the diagnostic fuel line after four or more repetitions, check the suction side of the fuel system for leaks. Refer to Procedure 006-003 in Section 6.

Remove the diagnostic fuel line

 
SMALL | MEDIUM | LARGE
   


 WARNING 

When servicing the engine do not rotate the crankshaft with a high-pressure fuel system joint open. Rotating the crankshaft can create highly pressurized fuel in the fuel system.  High-pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

NOTE: The engine can possibly run rough for several minutes until the air is out of the system.

If the engine will not start, begin cranking the engine. Attach the diagnostic fuel line to the Compuchek™ fitting at the inlet to the pressure side fuel filter (outlet to the fuel pump gear pump). Continue cranking the engine for 5 more seconds.

Stop cranking the engine and observe the orificed diagnostic fuel line. Allow the entrapped air to expand and exit through the diagnostic fuel line. Do not crank the engine longer than 30 seconds.

Repeat this process up to four times or until the engine starts. If air continues to exit the diagnostic fuel line after four or more repetitions, check the suction side of the fuel system for leaks. Refer to Procedure 006-003 in Section 6.

Remove the diagnostic fuel line

 
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Without Fuel Lift Pump


 CAUTION 

Use a clean side block-off plug to prevent fuel from entering the clean side (center) of the filter. Do not over fill the filter. Dirt or contaminants can damage the fuel system.

The fuel system should be primed after replacing the fuel filter or running the engine out of fuel.

To prime the fuel system, fill the suction-side and pressure-side fuel filters with clean diesel fuel.

Use a clean side block-off plug, if available, to prevent fuel from entering the clean side of the filter. Pour clean diesel fuel into the outer openings (dirty side) of the filter.

Use caution not to overfill the filter. Dirty fuel could enter the clean side (center cavity) of the filter when the clean side block-off plug is removed from the filter for installation.

Install the suction-side fuel filter. Refer to Procedure 006-066 in Section 6.

Install the pressure-side fuel filter. Refer to Procedure 006-065 in Section 6.

 
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 WARNING 

When servicing the engine do not rotate the crankshaft with a high pressure fuel system joint open. Rotating the crankshaft can create highly pressurized fuel in the fuel system.  High-pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

NOTE: The engine can possibly run rough for several minutes until the air is out of the system.

To assist in fuel system priming and removing air from the fuel system, an orificed diagnostic fuel line, Part Number 3164621, may be used to bleed air from the low-pressure fuel system.

Start the engine and allow it to stabilize. Attach the diagnostic fuel line to the Compuchek™ fitting at the inlet to the pressure-side fuel filter. Shut off the engine and observe the orificed diagnostic fuel line. Allow the entrapped air to expand and exit through the diagnostic fuel line.

Repeat this process up to four times or until air no longer exits the diagnostic fuel line. If air continues to exit the diagnostic fuel line after four or more repetitions, check the suction side of the fuel system for leaks. Refer to Procedure 006-003 in Section 6.

 
SMALL | MEDIUM | LARGE
   


 WARNING 

When servicing the engine do not rotate the crankshaft with a high pressure fuel system joint open. Rotating the crankshaft can create highly pressurized fuel in the fuel system.  High-pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

NOTE: The engine can possibly run rough for several minutes until the air is out of the system.

If the engine will not start, begin cranking the engine. Attach the diagnostic fuel line to the Compuchek™ fitting at the inlet to the pressure-side fuel filter. Continue cranking the engine for 5 more seconds.

Stop cranking the engine and observe the orificed diagnostic fuel line. Allow the entrapped air to expand and exit through the diagnostic fuel line. Do not crank the engine longer than 30 seconds.

Repeat this process up to four times or until the engine starts. If air continues to exit the diagnostic fuel line after four or more repetitions, check the suction side of the fuel system for leaks. Refer to Procedure 006-003 in Section 6.

 
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Last Modified:  28-Jun-2010