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. (127 – 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. Connect a manometer to the tapped hole.
3. Start and run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
4. Run the engine speed to full load.
[a] If the exhaust back pressure at full load is less than 10.1 kPa (3.0 in. Hg), check the
fuel injectors, refer to section 8.5. Shut down the engine.
[b] If the exhaust back pressure at full load is 10.1 kPa (3.0 in. Hg) or greater,
refer to section 8.4.1. Shut down the engine.
8.4.1
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 section 8.4.1.1.
8.4.1.1
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. Refer to section 8.4 for exhaust caution before proceeding. 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.
[a] If the engine exhaust emission appears normal, no further troubleshooting is required. Shut down the engine.
[b] If the engine exhaust emission is excessively black or gray, shut down the engine. Check the fuel injectors; refer to section 8.5.
