MBE 900 – Section 15.6 No Start (Engine Will Not Rotate)

Section 15.6
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

Section 15.6.1
Troubleshooting Procedure for Discharged Battery

To determine if a discharged battery is causing the engine not to start, measure and record the voltage at the battery terminals; refer to OEM guidelines.‪

1. If, after charging, the voltage recorded is below OEM specifications, 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 "15.6.2 Discharged Battery Resolution" .
2. If the voltage recorded is at recommended OEM specifications and the engine failed to start, check the magnetic switch; refer to "15.6.3 Troubleshooting Procedure for a Defective Magnetic Switch" .

Section 15.6.2
Discharged Battery Resolution

Perform the following steps for battery replacement:‪

1. Replace the battery; refer to OEM guidelines.
2. Verify replacement of the battery; refer to "15.6.2.1 Test Engine with New Battery" .

Section 15.6.2.1
Test Engine with New Battery

To determine if the new battery resolved the no start 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. 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 or run, check the magnetic switch; refer to "15.6.3 Troubleshooting Procedure for a Defective Magnetic Switch" .

Section 15.6.3
Troubleshooting Procedure for a Defective Magnetic Switch

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

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 engine.
2. Clamp a heavy gage battery cable between the two large studs of the magnetic switch. See Figure "Basic Cranking Circuit" .
   

   Figure 1. Basic Cranking Circuit

   1. If the engine cranked with the jumper cable in place, the magnetic switch must be replaced; refer to "15.6.4 Magnetic Switch Replacement" .
   2. If the engine did not crank with the jumper cable in place, check the starter; refer to "15.6.5 Troubleshooting for a Defective Starter" .

Section 15.6.4
Magnetic Switch Replacement

Perform the following steps for magnetic switch replacement:‪

1. Replace the magnetic switch; refer to OEM guidelines.
2. Perform verification of magnetic switch replacement; refer to "15.6.4.1 Test Engine with New Magnetic Switch" .

Section 15.6.4.1
Test Engine with New Magnetic Switch

To determine if the magnetic switch replacement resolved the no start 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. 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 or run, check the starter; refer to "15.6.5 Troubleshooting for a Defective Starter" .

Section 15.6.5
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 "Cranking Motor Available Voltage Test" .
   

   1. Black Lead‪	4. Red Lead‪
   2. Starter Ground‪	5. Voltmeter‪
   3. Solenoid Terminal‪

   Figure 2. Cranking Motor Available Voltage Test

2. Place the black voltmeter lead to the starter ground terminal. See Figure "Cranking Motor Available Voltage Test" .
3. Engage the starter switch.
4. View the voltage reading on the meter.
   1. If the voltage is less than specification (refer to OEM guidelines) while cranking the engine, replace starter; refer to "15.6.6 Starter Replacement" .
   2. If the voltage is to specification (refer to OEM guidelines) while attempting to crank the engine, check for internal engine damage; refer to "15.6.7 Troubleshooting Procedure for Internal Engine Damage" .

Section 15.6.6
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 "15.6.6.1 Test Engine with New Starter" .

Section 15.6.6.1
Test Engine with New Starter

To determine if the new starter resolved no-start conditions, 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. ‪

• Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
• If the engine fails to start or run, check for internal engine damage. Refer to "15.6.7 Troubleshooting Procedure for Internal Engine Damage" .

Section 15.6.7
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 wiring harness; refer to "15.5.1 Troubleshooting Procedure for DDEC-ECU Wiring Harness" .
   2. If the engine binds and will not rotate freely, replace crankshaft bearings; refer to "1.6 Crankshaft" and cylinder liners.

Section 15.6.8
Internal Engine Damage Replacement

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

1. Replace the crankshaft bearings; refer to "1.6 Crankshaft" .
2. Replace the cylinder liners.
3. Verify replacement of components; refer to "15.6.8.1 Test Engine with Replaced Components" .

Section 15.6.8.1
Test Engine with Replaced Components

To determine if the new components resolved no start 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. 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 or run, call Detroit Diesel Customer Support Center at 313-592-5800.