MBE 4000 DDEC VI Troubleshooting – Section 4.1 Poor Vehicle Ground

Section 4.1
Poor Vehicle Ground

Check for poor vehicle ground as follows:‪

1. Remove the alternator drive belt.

   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. Start the engine.
3. Run the engine through operating range.
4. Listen for engine misfiring.
   1. If the engine is not misfiring, refer to "4.1.1 Negative Lead Repair" . Shut down the engine.
   2. If the engine is still misfiring, check for aerated fuel. Refer to "4.2 Aerated Fuel" .

Section 4.1.1
Negative Lead Repair

Repair the negative lead as follows:‪

1. Shut down the engine.
2. Remove negative lead(s) at frame ground stud near battery box.
3. Clean ground stud; refer to OEM guidelines.
4. Clean negative lead(s) terminal lugs with low grit sandpaper.
5. Repair any loose or damaged lead(s), using the splice method or rosin core solder.
6. Install negative lead(s) to frame ground stud; refer to OEM guidelines.
7. Install alternator drive belt.

   Note: Drive belts (Vee and poly–vee) should be replaced every 2,000 hours or 160,000 km (100,000 miles).

8. Verify negative lead repair; refer to "4.1.1.1 Verify Repairs" .

Section 4.1.1.1
Verify Repairs

Verify as follows:‪

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. Run engine speed up to the occurrence of the misfiring.
3. Listen for misfiring cylinder.
   1. If the engine is not misfiring, no further troubleshooting is required. Shut down the engine.
   2. If the engine is misfiring, check for aerated fuel. Shut down the engine; refer to "4.2 Aerated Fuel" .