941534 Volvo.Penta Elbow nipple, angle nipple

Probable Causes
Starting aids
Fuel supply
Unit injectors
Cooling system
Component wearRecommended Actions
Table 1
Troubleshooting Test Steps Values Results
1. Check for Active Diagnostic Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the Electronic Control Module (ECM). Refer to Troubleshooting, Electronic Service Tools if necessary.
B. Download the "Product Status Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
Troubleshoot any active codes before continuing with this procedure.
Active Codes
Result: Active codes are present.
Troubleshoot the active code.
Result: No active codes are present.
Proceed to Test Step 2.
2. Starting Aid
A. Check for proper operation of the jacket water heater circuit.
B. Verify that the glow plugs and coolant temperature sensor are operating correctly.
Refer to the machine System Operation manual.
Starting Aid
Result: The starting aids are operation properly.
Proceed to Test Step 3.
Result: The starting aids are not operating properly.
Make the necessary repairs.
3. Cooling System
A. Check for an internal coolant leak into the cylinder and/or exhaust.
Refer to Systems Operation/Testing and Adjusting for information on inspecting the cooling system.
Cooling System
Result: An internal leak is present.
Make the necessary repairs.
Result: An internal leak is not present.
Proceed to Test Step 4.
4. Check the Engine Oil Level and Obtain an Oil Sample
Check the oil level and obtain an oil sample. If the oil level is high, take an oil sample to check for fuel dilution. Refer to Troubleshooting, Oil Contains Fuel if fuel is present.
Oil
Result: The engine oil sample shows moitor or action required.
Make necessary repairs.
Result: The engine oil sample and oil level are OK.
Proceed to Test Step 5.
Result: The engine oil level is not at the correct level.
Determine root cause of why the oil level was high or low.
5. Check the Fuel System
Refer to Systems Operation/Testing and Adjusting, Fuel System for additional information.
A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only.
B. Ensure that the vent in the fuel cap is not filled with debris.
C. Inspect the fuel system for external leaks.
D. Check that there is no air in the clear primary fuel filter. Refer to Systems Operation/Testing and Adjusting, Low Fuel Pressure System-Test.
E. Change the primary fuel filter and the in-line filter for the fuel transfer pump.
F. Check fuel quality. Refer to Systems Operation/Testing and Adjusting, Fuel Quality - Test for the proper procedure. Check the fuel tank for debris or foreign objects which may block the fuel supply.
G. Check for the proper operation of the fuel transfer pump. Replace the pre-filter if excessive contamination or if the maintenance interval is exceeded. Refer to Systems Operation/Testing and Adjusting, Low Fuel Pressure System-Test for test information.
Fuel System
Result: The fuel system is OK.
Proceed to Test Step 6.
Result: The fuel system is not OK.
Make the necessary repairs.
6. Fuel Injectors
A. If service has been performed on the engine fuel system recently, verify that the injector trim codes in the Engine ECM match the injector for each cylinder. If injectors were moved between cylinders or if an injector was replaced and the injector trim codes were not updated in the Engine ECM, this can cause an engine miss.
B. Access the "Cylinder Cutout Test" in the "Diagnostic Tests" under the "Diagnostics" menu. Cut out each cylinder one at a time to listen for improvements in the engine. If engine sound improves while cutting out a specific cylinder or cylinders, then check that the injector(s) are working properly by using 440-6907 Injector Kit.
Note: The injector deliver quantity is not a reliable indicator of a failed injector. It is not recommended to use that test in determining if an injector is failed.
Fuel Injectors
Result: If injector(s) trim codes for each cylinder do not match what is in the Engine ECM, then refer to the Special Instruction, REHS9707for the procedure to install the new injector QR codes within the Engine ECM and on-line. Confirm that this resolves the issue.
Result: If injector(s) are found to be defective, then replace the injector(s). Refer to Disassembly and Assembly, Electronic Unit Injector - Remove and Install. Refer to the Special Instruction, REHS9707for the procedure to install the new injector QR codes within the Engine ECM and on-line.
Confirm that this resolves the issue.
Note: If two or more injectors are not working properly, this is likely a result of water in the fuel, bad fuel, or contaminated fuel. Contaminated fuel can occur by pre-filling the fuel filter or contamination during a previous repair of the fuel system. The root cause needsto be determinedto prevent a repeat occurrence.
Result: There are no previous known services on fuel system and there was no noticeable improvement during the cylinder cut out test. The customer could have ordered injectors through parts and did not change the injector trim codes in the Engine ECM. Visually confirm that the injector trim code for each cylinder matches what is in the Engine ECM. Refer to the Special Instruction, REHS9707 for the procedure to install the new injector QR codes within the Engine ECM and on-line.
Proceed to Test Step 7.
7. Valve Lash Setting
A. Check the valve lash. Adjust the valve lash, if necessary.
Refer to Systems Operation/Testing and Adjusting, Engine Valve Lash - Inspect/Adjust.
Valve Lash
Result: The valve lash is set to the proper specification.
Proceed to Test Step 8.
Result: The valve lash is not set to the proper specification.
Set the valve lash to the proper specification.
8. Component Wear
A. Check for low compression.
Wear or damage to the following components can cause low compression:
• Piston
• Piston rings
• Cylinder bore
• Valves
• Cylinder Head Gasket
• Cylinder Head
Mechanical Components
Result: Low compression is present.
Make the necessary repairs.
Result: Low compression is not present.
Complete the procedure in the order in which the steps are listed.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).