Series 50 – Section 21.4 Faulty Exhaust System

Section 21.4
Faulty Exhaust System

To determine if a faulty exhaust system is causing excessive exhaust smoke, perform the following: ‪

1. Drill an 11/32 in. hole in the exhaust pipe, 5 to 12 in. (approximately 127 to 305 mm) from the turbocharger exhaust outlet.

   Note: The tapped hole must be in a comparatively straight area of the turbocharger exhaust outlet.

2. Tap the hole to accommodate an 1/8 in. pipe plug.
3. Connect a manometer to the tapped hole; refer to "29.1 Proper Use of Manometer" .
4. Start and run the engine.
5. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
6. Run the engine speed to full load.
   1. If the exhaust back pressure at full load is less than 3.0 in. Hg (10.1 kPa), check the fuel injectors; refer to "21.5 Faulty Fuel Injector" . Shut the engine down.
   2. If the exhaust back pressure at full load is 3.0 in. Hg (10.1 kPa) or greater, refer to "21.4.1 Engine Exhaust System Resolution" . Shut the engine down.

Section 21.4.1
Engine Exhaust System Resolution

Perform the following steps to resolve the engine exhaust system: ‪

1. Visually inspect the engine exhaust system; refer to OEM guidelines.
2. Repair and replace defective exhaust system components; refer to OEM guidelines.
3. Verify exhaust system resolution; refer to "21.4.1.1 Test the Engine with Replaced Exhaust System" .

Section 21.4.1.1
Test the Engine with Replaced Exhaust System

Perform the following steps to determine if replaced engine exhaust system components resolved excessive exhaust smoke condition: ‪

1. Start and run the engine.
2. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
3. Visually inspect exhaust for excessive smoke.
   1. If the engine exhaust emission appears normal, no further troubleshooting is required. Shut the engine down.
   2. If the engine exhaust emission is excessively black or gray, shut the engine down. Check the fuel injectors; refer to "21.5 Faulty Fuel Injector" .