C7.1 Engines and Generator Sets Caterpillar

Exhaust Has Excessive Black Smoke

Usage:

C7.1 770

If excessive black smoke is caused by an engine fault, the smoke will only be visible when the Diesel Particulate Filter (DPF) has also failed. Perform the following procedure to diagnose the cause of the black smoke and then investigate the failure of the DPF.

Note: A faulty DPF will allow some smoke to be visible. In this situation, there may not be a fault in the engine.

Probable Causes

Diagnostic codes
Parameters in the Electronic Control Module (ECM)
Air intake system or exhaust system
Valve lash
Turbochargers
Low compression (cylinder pressure)
Electronic unit injectors
Individual malfunctioning cylinder

Recommended Actions

Note: Complete the procedure in the order in which the steps are listed.

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Table 1
Troubleshooting Test Steps	Values	Results
1. Diagnostic Codes A. Download the Warranty Report and the Product Status Report with Histograms before performing any troubleshooting or clearing any diagnostic codes. Note: The downloaded information will be required by the Dealer Solutions Network (DSN) if troubleshooting assistance is needed. B. Use the electronic service tool to check for active or logged codes.	Diagnostic codes	Result: A diagnostic code is present. Repair: Troubleshoot the code. Result: A diagnostic code is not present. Proceed to Test Step 2.
2. Parameters in the Electronic Control Module (ECM) A. Use the electronic service tool to verify that the correct parameters are being used. Refer to Troubleshooting, "Configuration Parameters" for additional information.	Parameters	Result: The parameters are not correct. Repair: Input the correct parameters. Refer to Troubleshooting, "Configuration Parameters" for additional information. Result: The parameters are correct. Proceed to Test Step 3.
3. Air Intake and Exhaust System A. Observe the check engine lamp. Check for an air filter restriction indicator, if equipped. Replace a plugged air filters. Refer to the Operation and Maintenance Manual. B. Check the air inlet and exhaust system for restrictions and/or leaks.	Restrictions	Result: There are restrictions in the air inlet or exhaust system. Repair: Make the necessary repairs, Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System - Inspect" for additional information. Result: There are no restrictions in the air inlet or exhaust system. Proceed to Test Step 4.
4. Valve Lash A. Check the valve lash.	Valve lash	Result: The valve lash is incorrect. Repair: Check the valve lash. Refer to Systems Operation, Testing, and Adjusting, "Engine Valve Lash - Inspect" for the correct procedure. Result: The valve lash is correct. Proceed to Test Step 5.
5. Turbochargers Note: The turbochargers that are installed on the engine are non-serviceable items. If any mechanical fault exists, then the faulty turbocharger must be replaced. A. Ensure that the mounting bolts for the turbochargers are tight. B. Check that the oil drains for the turbochargers are not blocked or restricted. C. Check that the compressor housings for the turbochargers are free of dirt and debris. Make sure that the housings are not damaged. D. Check that the turbine housings for the turbochargers are free of dirt and debris. Make sure that the housings are not damaged. E. Check that the turbine blades rotate freely in the turbochargers. F. Ensure that the wastegate on the high-pressure turbocharger is adjusted correctly. Refer to Systems Operation, Testing, and Adjusting, "Turbocharger - Inspect". If the wastegate actuator is faulty, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".	Turbocharger	Result: There is a fault in one of the turbochargers. Repair: Repair the turbocharger or replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install". Result: The turbochargers are OK. Proceed to Test Step 6.
6. Low Compression (Cylinder Pressure) A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test".	Cylinder compression	Result: The results of the compression test are outside the specifications. Repair: Investigate the cause and rectify any faults. Note: Possible causes of low compression are shown in the following list: · Loose glow plugs · Faulty piston · Faulty piston rings · Worn cylinder bores · Worn valves · Faulty cylinder head gasket · Damaged cylinder head Result: The results of the compression test are OK. Proceed to Test Step 7.

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Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.

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NOTICE

Contact with high-pressure fuel may cause personal injury or death. Wait 10 minutes after the engine has stopped to allow fuel pressure to purge before any service or repair is performed on the engine fuel lines.

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Table 2
Troubleshooting Test Steps	Values	Results
7. Electronic Unit Injectors A. Use the electronic service tool to perform the automatic "Cylinder Cut Out Test". Note: If the compression test that was performed in Test Step 6 was satisfactory, the "Cylinder Cut Out Test" will identify any faulty injectors.	Electronic Unit Injectors	Result: A faulty injector is indicated. Repair: Remove any faulty electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove". Install new electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Install". Repeat the automatic "Cylinder Cut Out Test". If the fault is still apparent, remove the replacement electronic unit injector and install the original electronic unit injector. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove" and Disassembly and Assembly, "Electronic Unit Injector - Install". Result: All injectors are OK. Proceed to Test Step 8.
8. Individual Malfunctioning Cylinders A. With the engine speed at a fast idle, use the electronic service tool to perform the manual "Cylinder Cut Out Test". As each cylinder is cut out, listen for a change in the sound from the engine. When a cylinder is cut out, there should be a noticeable change in the sound of the engine. If a change in the sound of the engine is not noted, the isolated cylinder is not operating under normal conditions. If the isolation of a cylinder results in a change in the sound that is less noticeable, the cylinder may be operating below normal performance.	Cylinders	Result: The test indicates a faulty cylinder. Repair: Investigate the cause of the fault on any cylinder that is not operating. Investigate the cause of the fault on any cylinder that is operating below normal performance. Result: The test indicates that all cylinders are OK. Contact the Dealer Solutions Network (DSN).