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MBE 900 – Section 15.5 Starting Difficulty (Engine Rotates)

Section 15.5
Starting Difficulty (Engine Rotates)

There are several causes for the engine to have starting difficulty. These probable causes are:‪

  • DDEC-ECU Wiring Harness Damage
  • Empty Fuel Tank
  • Low Battery Voltage
  • Corroded or Damaged Battery Terminals
  • Defective Magnetic Switch
  • Defective Starter
  • Low Cranking Speed
  • Faulty Fuel Supply Valve
  • Plugged Fuel Filter(s)
  • Faulty Fuel Pump
  • Aerated Fuel
  • Restrictive Air Filter
  • Low Compression

Section 15.5.1
Troubleshooting Procedure for DDEC-ECU Wiring Harness

To determine if the DDEC-ECU wire harness is causing starting difficulty, perform the following steps:‪

  1. Turn the ignition switch to the ON position.
  2. Install the Diagnostic Data Link (DDL) adaptor to the data cable and plug the adaptor into the DDL connector in the vehicle.
  3. Determine if DDEC-ECU data is being received by the DDR. If no data is being received by the DDR, check for intermittent code or a fault and no codes by doing the following:
    1. Check for poor mating of the connector halves or terminals not fully seated in the connector body (backed-out terminals).
    2. Look for improperly formed or damaged terminals. All connector terminals in the problem circuit should be carefully inspected to determine proper contact tension. Use a mating terminal to test the contact tension.
    3. Electrical system interference may be caused by a defective relay, or a switch causing an electrical surge. Look for problems with the charging system (alternator, etc.). In certain cases, the problem can be made to occur when the faulty component is operated as in the case of a relay.
    4. Verify alternator grounds are clean and making good contact. Disconnect the alternator belt to test.
    5. Wiggle wires and harnesses to try to make the problem active or to occur again.
  4. If data is being received by the DDR, check the vehicle circuit breakers or fuses; refer to "15.5.2 Vehicle Circuit Breakers or Fuses Check" .

Section 15.5.2
Vehicle Circuit Breakers or Fuses Check

To determine if the vehicle circuit breakers are causing starting difficulty, visually check DDEC-ECU circuit breakers or fuses to determine if circuit breaker(s) or fuse(s) are tripped or blown.‪

  1. If circuit breakers are tripped, determine cause and repair or replace as necessary; refer to OEM guidelines. Perform validation; refer to "15.5.4.1 Test Engine with Repaired Power Harness" .
  2. If circuit breakers are not tripped, measure the voltage at the DDEC-ECU power harness. An Electronic Control Troubleshooting Guide is currently under development for this procedure. Contact DDC Customer Support Center at 313-592-5800 in the interim.

Section 15.5.3
DDEC-ECU Power Harness Voltage Test

An Electronic Control Troubleshooting Guide is currently under development. Contact DDC Customer Support Center at 313-592-5800 in the interim.‪

Section 15.5.4
Power Harness Repair

Perform the following steps to repair the power harness:‪

  1. Repair the damage to the power harness.
  2. Verify repair of the power harness; refer to "15.5.4.1 Test Engine with Repaired Power Harness" .
Section 15.5.4.1
Test Engine with Repaired Power Harness

To determine if the repair resolved the starter difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check for an empty fuel tank; refer to "15.5.5 Troubleshooting Procedure for an Empty Fuel Tank" .

Section 15.5.5
Troubleshooting Procedure for an Empty Fuel Tank

To determine if an empty fuel tank is causing starting difficulty, check the amount of fuel in fuel tank; refer to OEM guidelines.‪

    ‪

  1. If fuel is at recommended level, check for a weak battery; refer to "15.5.7 Troubleshooting Procedure for Low Battery Voltage" .
  2. If fuel is below recommended level, refer to "15.5.6 Low Fuel Level Resolution" .

Section 15.5.6
Low Fuel Level Resolution

Perform the following steps in order to resolve low fuel level:‪

  1. Fill fuel tank to full; refer to OEM guidelines.
  2. Verify fuel tank refill; refer to "15.5.6.1 Test Engine with Filled Tank" .
Section 15.5.6.1
Test Engine with Filled Tank

To determine if a filled fuel tank resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the battery; refer to "15.5.7 Troubleshooting Procedure for Low Battery Voltage" .

Section 15.5.7
Troubleshooting Procedure for Low Battery Voltage

To determine if a weak battery is causing starting difficulty, measure the battery voltage; refer to OEM guidelines.‪

  1. If voltage is between 10.5 - 14 volts (21 - 26 volts for a 24-volt system), check the terminals for corrosion or damage; refer to "15.5.9 Troubleshooting Procedure for Corroded or Damaged Battery Terminals" .
  2. If voltage is less than 10.5 volts (21 volts for a 24-volt system), battery replacement is necessary; refer to "15.5.8 Battery Replacement" .

Section 15.5.8
Battery Replacement

Perform the following steps for battery repair:‪

  1. Remove and replace the battery; refer to OEM guidelines.
  2. Verify battery replacement; refer to "15.5.8.1 Test Engine with Replaced Battery" .
Section 15.5.8.1
Test Engine with Replaced Battery

To determine if the battery replacement resolved starting difficulty, attempt to start and run the engine.‪

warning

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. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the terminals; refer to "15.5.9 Troubleshooting Procedure for Corroded or Damaged Battery Terminals"

Section 15.5.9
Troubleshooting Procedure for Corroded or Damaged Battery Terminals

To determine if corroded or damaged terminals are causing starting difficulty, visually inspect terminals for corrosion or damage.‪

  1. If corrosion or damage are not found, check the magnetic switch; refer to "15.5.11 Troubleshooting Procedure for Defective Magnetic Switch" .
  2. If corrosion or damage are found, repair is necessary; refer to "15.5.10 Corroded or Damaged Battery Terminal Repair" .

Section 15.5.10
Corroded or Damaged Battery Terminal Repair

Perform the following steps to repair corroded or damaged battery terminals:‪

  1. Repair or replace any corroded or damaged terminals; refer to OEM guidelines.
  2. Verify repair of corroded or damaged terminals; refer to "15.5.10.1 Test with Repaired Battery Terminals" .
Section 15.5.10.1
Test with Repaired Battery Terminals

To determine if the repair resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the magnetic switch; refer to "15.5.11 Troubleshooting Procedure for Defective Magnetic Switch" .

Section 15.5.11
Troubleshooting Procedure for Defective Magnetic Switch

To determine if a defective magnetic switch is causing starting difficulty:‪

warning

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 the engine.
  2. Clamp a heavy gauge battery jumper cable between the two large studs of the magnetic switch. See Figure "Basic Cranking Circuit" .
    Click to see this graphic in a separate window

    Figure 1. Basic Cranking Circuit

    1. If the engine cranked with the jumper cable in place, the magnetic switch must be replaced; refer to "15.5.12 Magnetic Switch Replacement" .
    2. If the engine did not crank with the jumper cable in place, check the starter; refer to "15.5.13 Troubleshooting Procedure for a Defective Starter" .

Section 15.5.12
Magnetic Switch Replacement

Perform the following steps for magnetic switch replacement:‪

  1. Replace the magnetic switch; refer to OEM guidelines.
  2. Verify magnetic switch replacement; refer to "15.5.12.1 Test Engine with Replaced Magnetic Switch" .
Section 15.5.12.1
Test Engine with Replaced Magnetic Switch

To determine if the magnetic switch replacement resolved the starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the starter; refer to "15.5.13 Troubleshooting Procedure for a Defective Starter" .

Section 15.5.13
Troubleshooting Procedure for a Defective Starter

To determine if a defective starter is causing starting difficulty, perform the following steps:‪

  1. Place the red lead of a voltmeter to the solenoid “BAT” terminal; see Figure "Starting Motor Available Voltage Test" .
    Click to see this graphic in a separate window

     1. Black Voltmeter Lead‪

     4. Harness Tube‪

     2. Starter Ground Terminal Lug‪

     5. Volt Ohm Meter‪

     3. Red Voltmeter Lead‪

    Figure 2. Starting Motor Available Voltage Test

  2. Place the black voltmeter lead to the starter ground terminal; see Figure "Basic Cranking Circuit" .
  3. Engage the starter switch.
  4. View the voltage reading on the meter.
    1. If the voltage is less than specification while cranking the engine, replacement is necessary; refer to "15.5.14 Starter Replacement" .
    2. If the voltage is to specification while cranking the engine, check the cranking speed; refer to "15.5.15 Troubleshooting Procedure for Low Cranking Speed" .

Section 15.5.14
Starter Replacement

Perform the following steps for starter replacement:‪

  1. Replace the starter. Refer to "8.1 Starter" .
  2. Verify replacement of starter; refer to "15.5.14.1 Test Engine with Replaced Starter" .
Section 15.5.14.1
Test Engine with Replaced Starter

To determine if the replaced starter resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the cranking speed; refer to "15.5.15 Troubleshooting Procedure for Low Cranking Speed" .

Section 15.5.15
Troubleshooting Procedure for Low Cranking Speed

To determine if low cranking speed is causing starting difficulty, install a tachometer to the engine and record engine revolution while cranking the engine. Refer to OEM guidelines.‪

Section 15.5.16
Low Cranking Speed Repair

Perform the following steps for low cranking speed repair:‪

  1. Drain the engine oil. Refer to "13.1.4 Engine Oil and Filter Changing" .
  2. Remove the oil filter(s).
  3. Install new oil filter(s). Refer to "13.1.4 Engine Oil and Filter Changing" .
  4. Refill the lubrication system with new oil.
  5. Verify low cranking speed repair; refer to "15.5.16.1 Test Engine with Replaced Oil" .
Section 15.5.16.1
Test Engine with Replaced Oil

To determine if the replaced oil resolved starting difficulty, perform the following steps:‪

warning

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. ‪

Section 15.5.17
Troubleshooting Procedure for the Fuel Supply Valve

To determine if the fuel supply valve is causing starting difficulty, check that the fuel supply valve is open; refer to OEM guidelines.‪

  1. If the fuel supply valve is open, check the fuel filters; refer to "15.5.19 Troubleshooting Procedure for Plugged Fuel Filter(s)" .
  2. If the fuel supply valve is closed, repair is necessary; refer to "15.5.18 Fuel Supply Valve Repair" .

Section 15.5.18
Fuel Supply Valve Repair

Perform the following steps for fuel supply valve repair:‪

  1. Correct valve operation or replace valve.
  2. Prime the fuel system; refer to "11.1.5 Priming the Fuel System" .
  3. Verify fuel supply valve repair; refer to "15.5.18.1 Test Engine with Fuel Supply Valve Open" .
Section 15.5.18.1
Test Engine with Fuel Supply Valve Open

To determine if opening the fuel supply valve resolved starting difficulty, perform the following steps :‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the fuel filters; refer to "15.5.19 Troubleshooting Procedure for Plugged Fuel Filter(s)" .

Section 15.5.19
Troubleshooting Procedure for Plugged Fuel Filter(s)

To determine if a plugged fuel filter(s) is causing starting difficulty, perform the following steps:‪

  1. Disconnect the fuel line return hose from the fitting located at the fuel tank.
  2. Place the opened end of the fuel line into a five gallon container.
    warning

    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. ‪
  3. Start the engine.
  4. Run the engine at 1000 rpm.
  5. Clock fuel rate for one minute.
  6. Measure the amount of fuel delivered into the container.
    1. If the fuel flow is greater than 1.7 L/min. (0.5 gal/min.) and aerated (small bubbles), check for air in fuel; refer to "15.5.23 Troubleshooting Procedure for Aerated Fuel" .
    2. If the fuel flow is less than 1.7 L/min. (0.5 gal/min.), replace the fuel filters; refer to "15.5.20 Plugged Fuel Filter(s) Replacement" .

Section 15.5.20
Plugged Fuel Filter(s) Replacement

Perform the following steps to replace the fuel filter(s):‪

  1. Replace the fuel filter; refer to "13.1.3 Main Fuel Filter Element Changing" .
  2. Test the engine to determine if starting has been improved; refer to "15.5.20.1 Test Engine with Replaced Fuel Filters" .
Section 15.5.20.1
Test Engine with Replaced Fuel Filters

To determine if the replaced fuel filters resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check the fuel pump; refer to "15.5.21 Troubleshooting Procedure for Fuel Pump" .

Section 15.5.21
Troubleshooting Procedure for Fuel Pump

To determine if the fuel pump is causing starting difficulty, perform the following:‪

warning

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. If pressure at idle speed (600–650 rpm) is -0.09 to -0.12 bar (-1.3 to -1.7), check for aerated fuel. Refer to "15.5.23 Troubleshooting Procedure for Aerated Fuel" .
  2. If pressure at idle speed (600–650 rpm) is less than -0.09 to -0.12 bar (-1.3 to -1.7), refer to Table .
  3. If pressure at idle speed (600–650 rpm) is greater than -0.09 to -0.12 bar (-1.3 to -1.7), refer to Table .
  4. If a no pressure reading is observed, replace the fuel pump, refer to "2.15.1 Fuel Pump Removal" .

    5. Check fuel intake pressure upstream of fuel pump.‪

Section 15.5.22
Fuel Pump Replacement

Perform the following steps for fuel pump replacement:‪

  1. Replace the fuel pump: refer to "2.15.1 Fuel Pump Removal" .
    warning

    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. ‪
  2. Test the engine to determine if starting has been improved; refer to "15.5.22.1 Engine Test with Replaced Fuel Pump" .
Section 15.5.22.1
Engine Test with Replaced Fuel Pump

To determine if the replaced fuel pump resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check for aerated fuel; refer to "15.5.23 Troubleshooting Procedure for Aerated Fuel" .

Section 15.5.23
Troubleshooting Procedure for Aerated Fuel

To determine if aerated fuel is causing starting difficulty, perform the following steps:‪

  1. Disconnect the fuel line return hose from the fitting located at the fuel tank; refer to OEM guidelines.
  2. Place the opened end of the fuel line into a suitable container.
    warning

    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. ‪
  3. Start the engine.
  4. Run the engine at 1000 rpm.
  5. Visually check to see if air bubbles are rising to the surface of the fuel within the container.
    1. If air bubbles are present, repair is necessary; refer to "15.5.24 Aerated Fuel Resolution" .
    2. If air bubbles are not present, check for a restrictive air filter. Shut down the engine; refer to "15.5.25 Troubleshooting Procedure for Restrictive Air Filter" .

Section 15.5.24
Aerated Fuel Resolution

Perform the following steps for aerated fuel resolution:‪

  1. Shut down the engine.
  2. Tighten all fuel line connections between fuel tank and fuel pump; refer to OEM guidelines.
  3. Visually inspect all fuel lines between fuel tank and fuel pump for leaks.
  4. Replace damaged components as required; refer to OEM guidelines.
  5. Verify aerated fuel resolution; refer to "15.5.24.1 Test Engine with Aerated Fuel Resolution" .
Section 15.5.24.1
Test Engine with Aerated Fuel Resolution

To determine if aerated fuel resolution resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check for a restrictive air filter; refer to "15.5.25 Troubleshooting Procedure for Restrictive Air Filter" .

Section 15.5.25
Troubleshooting Procedure for Restrictive Air Filter

To determine if a restrictive air filter is causing starting difficulty, perform the following steps:‪

  1. Remove the air filter element; refer to OEM guidelines.
    warning

    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. ‪
  2. Attempt to start and run the engine.
    1. If the engine starts and runs, no further engine troubleshooting is required. Shut down the engine.
    2. If the engine fails to start and run, refer to "15.5.26 Air Filter Replacement" .

Section 15.5.26
Air Filter Replacement

Perform the following steps for air filter replacement:‪

  1. Visually inspect the air filter for clogging and replace as necessary; refer to OEM guidelines.
  2. Visually inspect gaskets for deterioration and replace as necessary; refer to OEM guidelines.
  3. Visually inspect air inlets for restrictions and clean as necessary; refer to OEM guidelines.
  4. Verify air filter replacement; refer to "15.5.26.1 Test Engine with Replaced Air Filter" .
Section 15.5.26.1
Test Engine with Replaced Air Filter

To determine if the replaced air filter resolved starting difficult, perform the following steps:‪

warning

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. Attempt to start the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, check compression; refer to "15.5.27 Troubleshooting Procedure for Low Compression" .

Section 15.5.27
Troubleshooting Procedure for Low Compression

To determine if low compression is causing starting difficulty, perform the following steps:‪

  1. Perform a cylinder compression test. Refer to "1.2.2.2 Compression Testing" .
  2. Compare cylinder compression test results to specifications as listed in Table "Compression Testing Specifications" .

    Description‪

    Pressure in kPa (psi)‪

    Compression Pressure at Starter Speed‪

    2800 (406)‪

    Permissible Difference between Individual Cylinders‪

    400 (58)‪
    Table 20. Compression Testing Specifications
    1. If cylinder pressure is below specifications, refer to "15.5.28 Low Compression Repair" .
    2. If cylinder pressure is within specifications, call Detroit Diesel Customer Support Center at 313-592-5800.

Section 15.5.28
Low Compression Repair

Perform the following steps for low compression repair:‪

  1. Remove cylinder head; refer to "1.2.1 Cylinder Head Removal" .
  2. Inspect the cylinder head for worn or damaged valves; refer to "1.17 Valves" .
  3. Replace damaged valves; refer to "1.17 Valves" .
  4. Inspect the cylinder kit components for worn or damaged liners; pistons or piston rings.
  5. Verify repairs made to cylinder head valve(s) or cylinder kit components; refer to "15.5.28.1 Test Engine with Repaired Cylinder Head Valve(s), and Cylinder Kit" .
Section 15.5.28.1
Test Engine with Repaired Cylinder Head Valve(s), and Cylinder Kit

To determine if the cylinder head valve and cylinder kit repair resolved starting difficulty, perform the following steps:‪

warning

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. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
  2. If the engine fails to start and run, call the Detroit Diesel Customer Support Center at 313-592-5800.

MBE 900 Service Manual - 6SE414
Generated on 10-13-2008

Troubleshooting List of Contents

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