C175 Tier 4 Final Engines for Off-Highway Trucks Caterpillar

Exhaust Has Excessive Black Smoke

Usage:

793F D3T

Use this procedure to troubleshoot exhaust with excessive black smoke.

Probable Causes

Software
Inlet air restriction
Exhaust restriction
Sensor
Cylinder Cutout Test
Gear train
Fuel injector

Recommended Actions

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Table 1
Troubleshooting Test Steps	Values	Results
1. Ensure that the latest Flash File Software is Installed in the ECM A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Use Cat ET to verify that the correct flash file is being used.	Flash File	Result: The latest flash file is installed. Proceed to Test Step 2. Result: The latest flash file is not installed. Repair: Perform the following procedure: 1. Download the latest flash file from SIS web. 2. Install the software into the ECM. Refer to Troubleshooting, "ECM Software - Install" for additional information. If the problem is not resolved, proceed to Test Step 2.
2. Check for a Restriction in the Inlet Air System A. Check the air filter restriction indicator, if equipped. Refer to the Operation and Maintenance Manual. B. Measure the inlet air restriction for each turbocharger. Refer to Troubleshooting, "Inlet Air Is Restricted" for additional information.	Restriction	Result: The inlet air restriction is OK. Proceed to Test Step 3. Result: The inlet air restriction is NOT OK. An imbalance in the system is discovered. Repair: Repair or replace damaged inlet air system components. Equalize the inlet air restriction for each of the turbochargers. If the problem is not resolved, proceed to Test Step 3.
3. Check for a Restriction in the Exhaust System A. Visually inspect the exhaust for signs of restrictions. Visually inspect the catalyst for restrictions.	Restriction	Result: There are no exhaust restrictions. Proceed to Test Step 4. Result: There are exhaust restrictions. Repair: Repair or replace damaged exhaust system components. Proceed to Test Step 5.
4. Check for Proper Operation of the Intake Manifold Pressure Sensor A. Connect Cat ET. B. Use Cat ET to monitor following pressure: - "Boost Pressure" C. Ensure that the reading is steady and varies with engine speed and load. D. Verify that the status of the "Intake Manifold Pressure" is 0 kPa (0 psi) when the engine is not running.	Sensor	Result: The intake manifold pressure sensor appears to be operating correctly. Proceed to Test Step 5. Result: There appears to be a problem with the intake manifold pressure sensor. Repair: Replace the intake manifold pressure sensor. If the problem is not resolved, proceed to Test Step 5.
5. Perform a Cylinder Cutout Test A. Connect to Cat ET. B. Perform a cylinder cutout test to determine which cylinder is causing the black smoke complaint.	Cylinder Cutout Test	Result: The black smoke could not be isolated to a single cylinder. Proceed to Test Step 6. Result: The black smoke was isolated to a single cylinder. Repair: A failed fuel injector has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last two fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (0 ± 1160 psi) prior to servicing the fuel system. Repair: Replace the suspect injector. Refer to the Disassembly and Assembly for the appropriate procedure. Verify that the repair resolved the complaint. Return to service.
6. Check the Valve Lash A. Refer to Testing and Adjusting, "Valve Lash - Adjust" for additional information.	Valve Lash	Result: The hydraulic lash adjustments are OK. Proceed to Test Step 7. Result: The hydraulic lash adjustments are NOT OK. Repair: Refer to Testing and Adjusting, "Valve Lash - Adjust (Hydraulic Lash Adjusters)" for additional information. If the problem is not resolved, proceed to Test Step 7.
7. Inspect the Gear Train A. Check the following gear train for damage: - Crankshaft gear - Camshaft drive gear B. Verify that the crankshaft and the camshaft drive gears are set with the proper orientation for engine timing. Refer to Testing and Adjusting, Camshaft Timing and Crankshaft Position for Valve Lash Setting.	Gear Train	Result: The gear train has excessive wear. Repair: Repair or replace damaged gear train components. Refer to the Disassembly and Assembly manual and the Reuse and Salvage Guidelines manual for additional information. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).