MBE 900 – Section 15.13 Lack of Power

Section 15.13
Lack of Power

There are several causes for lack of power. These probable causes are:‪

• Aerated Fuel
• High Fuel Pressure
• High Fuel Temperature Return
• Faulty Overflow Valve
• Restricted Air Cleaner Element
• Restricted or Cracked Charge Air Cooler or Leaking Intake Manifold
• Faulty Exhaust System
• High Inlet Air Temperature
• Incorrect Camshaft Timing

Section 15.13.1
Troubleshooting Procedure for Aerated Fuel

To determine if aerated fuel is causing lack of power, perform the following steps:‪

1. Test for aerated fuel.
2. Disconnect the fuel line return hose from the fitting located at the fuel tank; refer to OEM guidelines.
3. Place the open end of the fuel line into a suitable container.

   PERSONAL INJURY ‪
   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

4. Start and run the engine.
5. Operate the engine at 1000 rpm.
6. Visually check to see if air bubbles are rising to the surface of the fuel that collects within the container.
   1. If air bubbles are not present, shut down the engine, check for high fuel pressure; refer to "15.13.3 Troubleshooting Procedure for High Fuel Pressure" .
   2. If air bubbles are present, shut down the engine; refer to "15.13.2 Aerated Fuel Resolution" .

Section 15.13.2
Aerated Fuel Resolution

Perform the following steps to resolve aerated fuel condition:‪

1. Tighten all fuel line connections between fuel tank and fuel pump; refer to OEM guidelines.
2. Visually inspect all fuel lines between fuel tank and fuel pump for leaks.
3. Repair damaged components as required; refer to OEM guidelines.
4. Verify aerated fuel resolution; refer to "15.13.2.1 Test the Engine with Aerated Fuel Resolution" .

Section 15.13.2.1
Test the Engine with Aerated Fuel Resolution

Perform the following steps to determine if aerated fuel resolution has resolved lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Run the engine at idle with a no-load condition for approximately five minutes, allowing the engine coolant to reach normal operating range.
3. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check for high fuel pressure; refer to "15.13.3 Troubleshooting Procedure for High Fuel Pressure" .

Section 15.13.3
Troubleshooting Procedure for High Fuel Pressure

To determine if high fuel pressure is causing a lack of power, perform the following steps:‪

1. Remove the fuel temperature sensor. See Figure "Disconnecting the Sensor" .
   

   1. Fuel Temperature Sensor‪

   2. Engine Wiring Harness‪

   Figure 1. Disconnecting the Sensor

2. Install the adaptor and banjo fitting, part of kit (J-46377) , and high pressure line (J-46372) . See Figure "Connecting the Adaptor" .
   

   1. Banjo Fitting‪	3. Adaptor from kit J-46377‪
   2. Solenoid Unit Pump‪

   Figure 2. Connecting the Adaptor

3. Attach a calibrated gauge (J-46378) capable of reading 0-100 psi, to the high-pressure fuel line (J-46372) , leading to the tee-fitting. See Figure "Attaching the Calibrated Gauge" .
   

   1. Engine Trim Panel‪	3. Fuel Temperature Sensor‪
   2. Engine Wiring Harness‪

   Figure 3. Attaching the Calibrated Gauge

   PERSONAL INJURY ‪
   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

4. Start and run the engine to the speeds listed in Table "Fuel Pressure at Various Speeds" and record the fuel pressure.

   Engine Speed, rpm‪	Fuel Pressure, kPa (psi)‪
   600-650‪	430 (62)‪
   2500‪	400-650 (58-94)‪

   Table 7. Fuel Pressure at Various Speeds
5. Shut down the engine.
6. Remove the adaptor, banjo fitting, high pressure line, and high pressure gauge.
7. Reinstall the fuel temperature sensor.
8. Analyze the measure fuel pressure readings.
   1. If the fuel pressure is within specifications listed in Table "Fuel Pressure at Various Speeds" , check for high fuel temperature return; refer to "15.13.6 Troubleshooting Procedure for High Fuel Temperature Return" .
   2. If the fuel pressure is greater than specifications listed in Table "Fuel Pressure at Various Speeds" , refer to "15.13.5 Overflow Valve Replacement" .

Section 15.13.4
Troubleshooting Procedure for Faulty Overflow Valve

To determine if a faulty overflow valve is causing a lack of power, perform the following steps:‪

1. Run Fuel system Test #1: Downstream Pressure Test. Refer to "15.3.2 Test #1: Downstream Pressure Test" .
2. If Test #1 indicates faulty overflow valve, proceed to step 3.
3. Run fuel system Test #3: Flow Test – At Fuel Filter. Refer to "15.3.4 Test #3: Flow Test — At Fuel Filter" .
4. If the overflow valve is found to be faulty, replace the overflow valve. Refer to "15.13.5 Overflow Valve Replacement" .

Section 15.13.5
Overflow Valve Replacement

Perform the following steps to replace the overflow valve.‪

1. Remove the overflow valve from the fuel return line.
2. Install a new overflow valve. Tighten the valve to 48-52 N·m (35-38 lb·ft). See Figure "Overflow Valve Location" .
   

   1. Unit Pump‪	4. Overflow Valve‪
   2. Bypass to Fuel Return Port‪	5. Constant Ventilation (overflow)‪
   3. Nozzle Holder‪

   Figure 4. Overflow Valve Location

3. Verify overflow valve replacement; refer to "15.13.5.1 Test the Engine with Replaced Overflow Valve" .

Section 15.13.5.1
Test the Engine with Replaced Overflow Valve

Perform the following steps to determine if the replaced overflow valve has resolved lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Run the engine at idle with a no-load condition for approximately five minutes, allowing the engine coolant to reach normal operating range.
3. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check for high fuel temperature return; refer to "15.13.6 Troubleshooting Procedure for High Fuel Temperature Return" .

Section 15.13.6
Troubleshooting Procedure for High Fuel Temperature Return

To determine if high fuel temperature return is causing lack of power, perform the following steps:‪

1. Test for high fuel temperature return.
2. Analyze the high fuel temperature test results.
   1. If the return fuel temperature is less than or equal to 60°C (140°F), check for air cleaner restriction; refer to "15.13.8 Troubleshooting Procedure for Restricted Air Cleaner Element" .
   2. If the return fuel temperature is greater than 60°C (140°F), resolve the high fuel temperature return condition; refer to "15.13.7 High Fuel Temperature Resolution" .

Section 15.13.7
High Fuel Temperature Resolution

Perform the following steps to resolve high fuel temperature return:‪

1. Remove and replace fuel filter(s); refer to "2.14.1 Fuel Filter Housing Removal" .
2. Verify high fuel temperature repair; refer to "15.13.7.1 Test the Engine with Resolved High Fuel Temperature" .

Section 15.13.7.1
Test the Engine with Resolved High Fuel Temperature

Perform the following steps to determine if high fuel temperature repairs have resolved lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If lack of power did not occur during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of occurred during the test drive, shut down the engine. Check for a restricted air cleaner element; refer to "15.13.8 Troubleshooting Procedure for Restricted Air Cleaner Element" .

Section 15.13.8
Troubleshooting Procedure for Restricted Air Cleaner Element

To determine if a restricted air cleaner element is causing lack of power, perform the following steps:‪

1. Remove the air filter element from the air cleaner container; refer to OEM guidelines.
2. Visually inspect the air cleaner element for damage or clogging.
   1. If no damage or clogging is found, check the charge air cooler; refer to "15.13.10 Troubleshooting Procedure for Restricted or Cracked Charge Air Cooler" .
   2. If damage or clogging is found, refer to "15.13.9 Air Filter Element Replacement" .

Section 15.13.9
Air Filter Element Replacement

Perform the following steps to replace the air filter element:‪

1. Remove and replace the damaged or clogged air filter element; refer to OEM guidelines.
2. Verify air filter element replacement; refer to "15.13.9.1 Test the Engine with Replaced Air Filter Element" .

Section 15.13.9.1
Test the Engine with Replaced Air Filter Element

Perform the following steps to determine if the new air filter element has resolved lack of power:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If lack of power did not occur during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check the charge air cooler; refer to "15.13.10 Troubleshooting Procedure for Restricted or Cracked Charge Air Cooler" .

Section 15.13.10
Troubleshooting Procedure for Restricted or Cracked Charge Air Cooler

To determine if a restricted or cracked charge air cooler is causing lack of power, perform the following steps:‪

NOTICE:
To avoid engine damage, follow the installation instructions provided with the air-to-air charge air cooler test kit.‪

1. Visually inspect the core, tanks, and welds for cracks and holes. If cooler fails visual inspection replace the charge air cooler; refer to "15.13.11 Charge Air Cooler Replacement" .
2. Pressure test the charge air cooler;refer to "15.9.3.1 Pressure Testing the Charge Air Cooler" .
3. Evaluate the results from pressure testing the charge air cooler.
   1. If the pressure drop is 34 kPa (5 psi) or less in 15 seconds, the cooler is good. Check for faulty air intake manifold; refer to "15.13.12 Troubleshooting Procedure for a Faulty Air Intake Manifold Gasket" .
   2. If the pressure drop is greater than 34 kPa (5 psi) in 15 seconds, replace the charge air cooler; refer to "15.13.11 Charge Air Cooler Replacement" .

Section 15.13.11
Charge Air Cooler Replacement

Perform the following steps to replace the charge air cooler:‪

1. Remove and replace the charge air cooler; refer to OEM guidelines.
2. Verify replacement of the charge air cooler; refer to "15.13.12.1 Test the Engine with Replaced Charge Air Cooler or Air Intake Manifold Gasket" .

Section 15.13.12
Troubleshooting Procedure for a Faulty Air Intake Manifold Gasket

Perform the following steps to troubleshoot a faulty air intake manifold gasket:‪

1. Remove the air intake manifold; refer to "6.2.1 Intake Manifold Removal" .
2. Inspect the air intake manifold and gaskets.
3. Install the air intake manifold with new gaskets; refer to "6.2.2 Intake Manifold Installation" .
4. Verify repair of the intake manifold; refer to "15.13.12.1 Test the Engine with Replaced Charge Air Cooler or Air Intake Manifold Gasket" .

Section 15.13.12.1
Test the Engine with Replaced Charge Air Cooler or Air Intake Manifold Gasket

To determine if the repairs resolved the lack of power condition, perform the following steps:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check the exhaust system; refer to "15.13.13 Troubleshooting Procedure for a Faulty Exhaust System" .

Section 15.13.13
Troubleshooting Procedure for a Faulty Exhaust System

To determine if a faulty exhaust system is causing lack of power, perform the following steps:‪

1. Drill an 11/32 in. hole in the exhaust pipe, 125-305 mm (5-12 in.) from the turbocharger exhaust outlet.

   Note: The tapped hole must be in a comparatively straight area of the turbocharger exhaust outlet.

2. Tap the hole to accommodate a 1/8 in. pipe plug.
3. Connect a manometer calibrated to read pressure in kPa or inches of Hg.

   PERSONAL INJURY ‪
   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

4. Start and run the engine.
5. Run the engine at idle with a no-load condition for approximately five minutes, allowing the engine coolant to reach normal operating range, approximately 88-96°C (190-205°F).
6. Run the engine speed to full load.
   1. If the exhaust back pressure at full load is less than 12 kPa (3.5 in. Hg), check for high inlet air temperature; refer to "15.13.15 Troubleshooting Procedure for High Inlet Air Temperature" .
   2. If the exhaust back pressure at full load is 12 kPa (3.5 in. Hg) or greater, refer to "15.13.14 Engine Exhaust System Resolution" .

Section 15.13.14
Engine Exhaust System Resolution

Perform the following steps to resolve the engine exhaust system concern:‪

1. Visually inspect the engine exhaust system; refer to OEM guidelines.
2. Repair or replace defective exhaust system components; refer to OEM guidelines.
3. Verify exhaust system resolution; refer to "15.13.14.1 Test the Engine with Replaced Exhaust System" .

Section 15.13.14.1
Test the Engine with Replaced Exhaust System

Perform the following steps to determine if replaced engine exhaust system components have resolved the lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check for high inlet air temperature; refer to "15.13.15 Troubleshooting Procedure for High Inlet Air Temperature" .

Section 15.13.15
Troubleshooting Procedure for High Inlet Air Temperature

To determine if high inlet air temperature is causing lack of power, test/check the radiator fan, fan drive, or fan shroud for proper operation or configuration. Refer to OEM guidelines.‪

1. If the radiator fan, fan drive, or fan shroud pass the OEM test, check camshaft timing; refer to "15.13.17 Troubleshooting Procedure for Incorrect Camshaft Timing" .
2. If the radiator fan, drive or shroud did not operate correctly, refer to "15.13.16 Radiator Fan, Drive and Shroud Replacement" .

Section 15.13.16
Radiator Fan, Drive and Shroud Replacement

Perform the following steps to replace the radiator fan, drive, and or shroud:‪

1. Remove and replace the radiator fan, drive, and/or shroud; refer to OEM guidelines.
2. Verify replacement; refer to "15.13.16.1 Test the Engine with Radiator Fan, Fan Drive, or Fan Shroud Replacement" .

Section 15.13.16.1
Test the Engine with Radiator Fan, Fan Drive, or Fan Shroud Replacement

Perform the following steps to determine if replaced radiator fan, fan drive, or fan shroud resolved lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check camshaft timing; refer to "15.13.17 Troubleshooting Procedure for Incorrect Camshaft Timing" .

Section 15.13.17
Troubleshooting Procedure for Incorrect Camshaft Timing

To determine if incorrect camshaft timing is causing lack of power, check the camshaft timing; refer to "1.20.1.1 Camshaft Inspection" .‪

1. If the dial indicator reading on the unit pump lobe is 13.8 mm (0.54 in.) or above, no further troubleshooting in required.
2. If the dial indicator reading is not above 13.8 mm (0.54 in.), check engine timing; refer to "15.13.18 Engine Timing Resolution" .

Section 15.13.18
Engine Timing Resolution

Perform the following steps to resolve incorrect engine timing:‪

1. Perform an engine gear train timing check; refer to "1.7.2 Crankshaft Gear Installation" .
2. Verify engine timing resolution; refer to "15.13.18.1 Test Engine with Correct Timing" .

Section 15.13.18.1
Test Engine with Correct Timing

Perform the following steps to determine if corrected engine timing has resolved lack of power condition:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked. ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Call Detroit Diesel Customer Support Center at 313-592-5800.