C7.1 Engines For Caterpillar Built Machines Caterpillar

If excessive black smoke is caused by a fault in the engine, 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

• Software 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

Diagnostic Codes

Use one of the following methods to check for active diagnostic codes:

• The electronic service tool

• The display on the control panel

Electronic Service Tool

1. Connect the electronic service tool to the diagnostic connector.

2. Check for active diagnostic codes on the electronic service tool.

3. Investigate any active codes before continuing with this procedure. Refer to Troubleshooting, "Troubleshooting with a Diagnostic Code".

Display on the Control Panel

1. Check the display on the control panel for active diagnostic codes.

2. Troubleshoot any active codes before continuing with this procedure. Refer to Troubleshooting, "Troubleshooting with a Diagnostic Code".

Use the electronic service tool to check the setup of the throttle.

ECM Software

1. Connect the electronic service tool to the diagnostic connector and check for the following conditions:
   • Check for the correct engine serial number

   • Check for the correct arrangement number

   • Check for the correct software

2. Use the electronic service tool to verify any active diagnostic codes.

3. If diagnostic codes are present, the ECM must be programmed with the correct information.

4. If the repairs have not eliminated the fault, proceed to "Air Intake System or Exhaust System".

Air Intake System or Exhaust System

1. Ensure that the air filter is clean and serviceable.

2. Check the air intake and the exhaust system for the following defects:
   • Blockages

   • Restrictions

   • Damage to the air intake and exhaust lines and hoses

3. Make all necessary repairs to the engine.

4. If the fault has not been eliminated, proceed to "Valve Lash".

Valve Lash

Ensure that the valve lash is correct. Refer to Systems Operation, Testing, and Adjusting, "Engine Valve Lash - Inspect".

If the fault is not eliminated, proceed to "Turbochargers".

Turbochargers

Note: The turbochargers that are installed on this engine are nonserviceable items. If any mechanical fault exists, then the faulty turbocharger must be replaced.

1. Ensure that the mounting bolts for the turbochargers are tight.

2. Check that the oil drains for the turbochargers are not blocked or restricted.

3. Check that the compressor housings for the turbochargers are free of oil, dirt, debris, and damage.

4. Check that the turbine housings for the turbochargers are free of oil, dirt, debris, and damage.

5. Check that the turbine blades rotate freely in the turbochargers.

6. 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".

7. If necessary, replace the high-pressure turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".

8. Check that the repairs have eliminated the faults.

9. If the repairs have not eliminated the fault, proceed to "Low Compression (Cylinder Pressure)".

Low Compression (Cylinder Pressure)

1. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test ".

2. If low compression is noted on any cylinders, investigate the cause and rectify the cause.

   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

3. Perform all necessary repairs.

4. Ensure that the repairs have eliminated the faults.

5. If the repair does not eliminate the fault, refer to "Electronic Unit Injectors".

Electronic Unit Injectors

1. Use the electronic service tool to perform the automatic "Cylinder Cut Out Test". If the compression test that was performed in "Low Compression (Cylinder Pressure)" was satisfactory, the "Cylinder Cut Out Test" will identify any faulty injectors.

2. Remove any faulty electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove".

3. Install new electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Install".

4. Repeat the test in 1. 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".

5. If the fault is not eliminated, proceed to "Individual Malfunctioning Cylinder".

Individual Malfunctioning Cylinder

1. 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 causes a change in the sound that is less noticeable, the cylinder may be operating below normal performance. 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.

2. If all cylinders have been checked and no faults are detected, refer to the Troubleshooting Guide for the application.