MBE 4000 DDEC VI Troubleshooting – Section 4.4 Faulty Fuel Injector or Unit Pump

Section 4.4
Faulty Fuel Injector or Unit Pump

To determine if a faulty fuel injector or unit pump is causing the cylinder to misfire, check for the following items: ‪

1. Use the DDDL® version 7.0 or later to detect any fault codes.
2. Make sure that the transfer tube thrust bolt is installed at the proper torque of 40 Nm (30 lb ft). A leaking transfer tube may be identified by cylinder cut out evaluation.

Section 4.4.1
Faulty Fuel Injector or Unit Pump Repair

Replace the unit pump or fuel injector. Refer to the MBE 4000 Service Manual (6SE420), Chapter 2, “Fuel System”, for unit pump or fuel injector replacement.‪

Section 4.4.1.1
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 the engine speed up to the occurrence of the misfiring.
3. Listen for misfiring cylinder.
   1. If the engine is not misfiring, shut down the engine. No further troubleshooting is required.
   2. If the engine is misfiring, shut down the engine and check for a faulty MCM; refer to "4.5 Faulty MCM" .