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MBE 900 NO START (ENGINE WILL NOT ROTATE)

There are several causes for the engine to not start. These probable causes are: ‪

  • Discharged Battery
  • Defective Magnetic Switch
  • Defective Starter
  • Internal Engine Damage

Troubleshooting Procedure for Discharged Battery

To determine if a discharged battery is causing the engine not to start, perform the following steps: ‪

  1. Measure and record the voltage at the battery terminals; refer to OEMguidelines.
    1. If, after charging, the voltage recorded is below OEMspecifications , voltage is between 10.5 - 14 volts (21 - 26 volts for a 24-volt system), and the engine failed to start, replacement is necessary; refer to section .
    2. If the voltage recorded is at recommended OEMspecifications and the engine failed to start, check the magnetic switch; refer to section .

Discharged Battery Resolution

Perform the following steps for battery replacement: ‪

  1. Replace the battery; refer to OEMguidelines.
  2. Verify replacement of the battery; refer to section .
Test Engine with New Battery

Perform the following steps to determine if the new battery resolved the no start condition: ‪

  1. Attempt to start and run the engine.
    1. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
    2. If the engine fails to start or run, check the magnetic switch; refer to section .

Troubleshooting Procedure for a Defective Magnetic Switch

To determine if a defective magnetic switch is causing no start: ‪

  1. Start engine.
  2. Clamp a heavy gage battery cable between the two large studs of the magnetic switch. See Figure 20538 .

    Basic Cranking Circuit

    1. If the engine cranked with the jumper cable in place, the magnetic switch must be replaced; refer to section .
    2. If the engine did not crank with the jumper cable in place, check the starter; refer to section .

Magnetic Switch Replacement

Perform the following steps for magnetic switch replacement: ‪

  1. Replace the magnetic switch; refer to OEMguidelines.
  2. Perform verification of magnetic switch replacement; refer to section .
Test Engine with New Magnetic Switch

Perform the following steps to determine if the magnetic switch replacement resolved the no start condition: ‪

  1. Attempt to start and run the engine.
    1. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
    2. If the engine fails to start or run, check the starter; refer to section .

Troubleshooting for a Defective Starter

To determine if a defective starter is causing no start, perform the following steps: ‪

  1. Place the red lead of a voltmeter to the solenoid BAT terminal. See Figure 20539 .

    1. Black Lead ‪

    4. Red Lead ‪

    2. Starter Ground ‪

    5. Voltmeter ‪

    3. Solenoid Terminal ‪

    Cranking Motor Available Voltage Test

  2. Place the black voltmeter lead to the starter ground terminal. See Figure 20539 .
  3. Engage the starter switch.
  4. View the voltage reading on the meter.
    1. If the voltage is less than specification (refer to OEMguidelines) while cranking the engine, starter replacement is necessary; refer to section .
    2. If the voltage is to specification (refer to OEMguidelines)while attempting to crank the engine, check for internal engine damage; refer to section .

Starter Replacement

Perform the following steps for starter replacement: ‪

  1. Replace the starter; refer to section .
  2. Verify replacement of starter; refer to section .
Test Engine with New Starter

Perform the following steps to determine if the new starter resolved no start conditions: ‪

  1. Attempt to start and run the engine.
    1. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
    2. If the engine fails to start or run, check for internal engine damage. Refer to section .

Troubleshooting Procedure for Internal Engine Damage

To determine if internal engine damage is causing no start condition, perform the following steps: ‪

  1. Install a 3/4 in. breaker bar or ratchet and attempt to bar the engine over by hand.
  2. Determine the severity of internal engine damage.
    1. If the engine rotates freely, check the DDEC-ECU Control Unit wiring harness; refer to section .
    2. If the engine binds and will not rotate freely, replace crankshaft bearings; refer to section and cylinder liners.

Internal Engine Damage Replacement

Perform the following steps for crankshaft bearings, and cylinder liner replacement: ‪

  1. Replace the crankshaft bearings; refer to section .
  2. Replace the cylinder liners.
  3. Verify replacement of components; refer to section .
Test Engine with Replaced Components

Perform the following steps to determine if the new components resolved no start condition: ‪

  1. Attempt to start and run the engine.
    1. If the engine starts and runs, no further troubleshooting is required. Shut down the engine.
    2. If the engine fails to start or run, call Detroit Diesel Technical Service.