MBE 900 DDEC VI Troubleshooting – Section 9.12 Faulty Exhaust Brake Cylinder

Section 9.12
Faulty Exhaust Brake Cylinder

To determine if a faulty exhaust brake cylinder is causing excessive black or gray smoke, check exhaust brake cylinder for full movement of travel by applying regulated air to cylinder.‪

1. If movement of travel is not full, replace the exhaust brake cylinder; refer to "9.12.1 Test Engine for Replaced Exhaust Brake Cylinder" . Verify replacement of exhaust brake cylinder corrected the excessive exhaust smoke concern; refer to "9.12.1 Test Engine for Replaced Exhaust Brake Cylinder" .
2. If full movement of travel is obtained, refer to "9.13 Faulty Constant Throttle Valve Solenoid" .

Section 9.12.1
Test Engine for Replaced Exhaust Brake Cylinder

Perform the following steps to determine if the replaced engine brake cylinder resolved the excessive exhaust smoke condition:‪

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.
2. Run the engine at idle under no-load conditions for approximately five minutes, allowing the engine coolant to reach normal operating range, approximately 88-96°C (190-205°F).
3. Visually inspect exhaust for excessive smoke.
   1. If the engine smoke emission appears normal, no further troubleshooting is required. Shut down the engine.
   2. If the engine exhaust smoke is excessively black or gray, shut down the engine. Check the constant throttle valve; refer to "9.13 Faulty Constant Throttle Valve Solenoid" .