DD15 Troubleshooting

Section 16.5 Monitoring Low Fuel System Pressure

Section 16.5
Monitoring Low Fuel System Pressure

This procedure will allow the low pressure fuel system to be monitored using pressure gauges.‪

  1. Place a towel or container under the fitting for the low pressure pump out to catch any draining fuel.
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  2. Remove four 8mm plug fitting in each of the four lines: low pressure pump inlet (1), low pressure pump outlet (2), high pressure pump inlet (3), and high pressure pump outlet (4). Store fittings to be reinstalled when testing is complete.
  3. Insert four quick disconnect fittings into each of the four fuel line test ports.
  4. Torque each fitting to 8 Nm (6 ft/lb).
  5. Install priming port gauge J-48876.
  6. Prime the fuel system. Refer to "2.5 Engine Will Only Start Using An External Priming Source" .
  7. Start the engine; refer to "16.5.1 Fuel System Pressures" and compare the pressures to the tables found there.
  8. Remove test equipment

Section 16.5.1
Fuel System Pressures

Normal and abnormal fuel system pressure are listed in the following tables.‪

Normal System Pressures‪

Cold Engine 600 RPM‪

Cold Engine 1800 RPM‪

Warm Engine 600 RPM‪

Warm Engine 1800 RPM‪

LPP Inlet (in Hg‪

-8 to-9‪

-14‪

-7.5‪

-13.5‪

LPP Outlet (PSI)‪

78-80‪

104‪

73-74‪

97‪

HPP Inlet (PSI)‪

74-76‪

87‪

70-71‪

83‪

HPP Outlet (PSI)‪

2.5‪

4.5‪

2-2.5‪

4‪

Priming Port (PSI)‪

78-80‪

101‪

72-73‪

94-95‪

Table 1. Normal Fuel System Pressures

Abnormal Fuel System Pressures‪

Coalescer (at or past its useful life)‪

Final Filter (at or past its useful life)‪

Warm Engine 600 RPM‪

Warm Engine 1800 RPM‪

Warm Engine 600 RPM‪

Warm Engine 1800 RPM‪

LPP Inlet (in Hg)‪

-8.5‪

-13.5‪

-5.5‪

-6‪

LPP Outlet (PSI)‪

82‪

122‪

160+‪

160+‪

HPP Inlet (PSI)‪

72‪

90‪

65‪

66‪

HPP Outlet (PSI)‪

3‪

4‪

1-2‪

2‪

Priming Port (PSI)‪

75‪

105‪

160+‪

160+‪

Restricted Fuel Feed Line to Module

Restricted Fuel Return Line From Module

Warm Engine

600 RPM

Warm Engine

1000 RPM

Warm Engine

600 RPM

Warm Engine

1000 RPM

LPP Inlet (in Hg)‪

-12‪

-14.5‪

-4.5‪

-6.5‪

LPP Outlet (PSI)‪

69‪

80‪

75‪

91‪

HPP Inlet (PSI)‪

67‪

75‪

72‪

84‪

HPP Outlet (PSI)‪

1-2‪

1-2‪

4.5‪

5.5‪

Priming Port (PSI)‪

70‪

80‪

75‪

90‪

Air in System (connector at line to MCM)

Warm Engine

600 RPM

LPP Inlet (in Hg)‪

-1 to -5 (oscillating)‪

—‪

—‪

—‪

LPP Outlet (PSI)‪

14‪

—‪

—‪

—‪

HPP Inlet (PSI)‪

14‪

—‪

—‪

—‪

HPP Outlet (PSI)‪

1-2‪

—‪

—‪

—‪

Priming Port (PSI)‪

14‪

—‪

—‪

—‪

Table 2. Abnormal System Pressures


EPA07 DD15 Troubleshooting Guide - DDC-SVC-MAN-0029
Generated on 10-13-2008

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