Masas de agua superficial naturales

Probable Cause

Table 24

Troubleshooting Test Steps Values Results

1. Measure the Fuel Pressure

A. Make sure that sufficient fuel is in the fuel tank. Remove any air in the fuel system.

B. Look for leaks or suspect bends in the fuel line between the fuel tank and the fuel transfer pump. C. Check the outlet pressure of the fuel transfer pump.

Fuel Pressure

Result: The fuel pressure is

low.

Make the necessary repairs. Verify that the problem is resolved.

Result: The fuel pressure is

not low.

Proceed to Test Step 2.

2. Check for Air in the Fuel System

A. Inspect the fuel system for air leaks in the system.

Air in the fuel system

Result: Air is in the fuel

system.

Find the air leak in the fuel system. Repair the fuel system. Verify that the problem is resolved.

Result: Air is not in the fuel

system.

Proceed to Test Step 3.

3. Check the Valve Lash

A. Check the engine valve lash. Valve lash

Result: The valve lash is not

correct.

Adjust the valve lash. Verify that the problem is resolved.

Result: The valve lash is

correct.

Proceed to Test Step 4.

4. Check the Timing for the Fuel Injection Pump

A. Check the timing of the fuel injection pump. Adjust the timing or replace the fuel injection pump. Refer to the Specifications Module, "Fuel Injection Pump" topic for additional information.

B. Check the operation of the fuel rack linkage. C. Make sure that the high-pressure fuel lines are connected to the fuel injection nozzles in the correct order.

D. Make sure that the mounting bolts of the fuel injection pump are tightened to the correct torque. Inspect the fuel lines for leaks or for restrictions. The damaged fuel lines or fittings must be repaired or replaced.

Fuel injection pump timing

Result: The operation of the

fuel injection pump is not correct.

The fuel injection pump must be repaired or replaced. Verify that the problem is resolved.

Result: The operation of the

fuel injection pump is correct. Proceed to Test Step 5.

5. Inspect the Fuel Injection Nozzles

A. Run the engine at the rpm that gives maximum misfiring or rough running. Then, loosen a fuel line nut on the injection line for each cylinder. Loosen one nut

Fuel Injection Nozzles

Result: A fuel injection nozzle

is not operating correctly. Replace the suspect fuel injection nozzle.

at a time. Then, tighten that nut before the next fuel line nut is loosened. If loosening the fuel line nut does not affect the operation of the engine, the fuel injection nozzle is probably suspect. Test the fuel injection nozzle for that cylinder.

B. Make sure that the fuel injection nozzles are properly sealed in the threaded ports. Make sure that the fuel injection nozzles are correctly aligned in the threaded ports. Make sure that the fuel injection nozzles are tightened to the correct torque. Ensure that the gaskets and the seat washers are installed on the fuel injection nozzles correctly. Make sure that the bottom of the threaded ports are clean and free of debris. Make sure that the bottom of the threaded ports do not contain extra gaskets.

Make sure that all of the fuel injection nozzles are the correct type for the engine. Test the pressure setting of the fuel injection nozzles. Refer to the Specifications Module, "Fuel Injection Nozzles" topic for additional information. Verify that the problem is resolved.

Result: The fuel injection

nozzles are operating correctly. Proceed to Test Step 6.

6. Check the Engine Mounts

A. Check the engine mounts for proper installation. B. Check the engine mounts for correct positioning. C. Check the bolts of the engine mounts for correct tightening.

These conditions will cause a vibration.

Engine mounts

Result: The engine mounts are

not correctly tightened or the engine mounts are not mounted correctly.

Repair or replace the suspect components.

Verify that the problem is resolved.

Result: The engine mounts are

correctly tightened and the engine mounts are mounted correctly.

Proceed to Test Step 7.

7. Check the Fuel Quality

A. Check the fuel for contamination. Contamination

Result: The fuel contains

water, dirt, ice, or wax. Replace the fuel filters. Replace the fuel in the fuel tank with clean fuel. Verify that the problem is resolved.

Result: The fuel does not

contain water, dirt, ice, or wax. Proceed to Test Step 8.

8. Check the Cylinder Compression

A. Starting the engine may be difficult in warm

weather. The engine may not start in cold weather. Low compression is most frequently caused by the

following conditions:

· Piston rings are worn or broken. · The piston height is incorrect. · The piston is damaged.

· The fuel injection nozzles are not seated correctly. · The valve lash requires adjustment.

· The fuel injection pump timing is incorrect. · The engine timing is incorrect.

· When an inlet valve or an exhaust valve is fully

seated, gases leak past the valve head.

Cylinder compression

Result: The cylinders have

low compression.

Make the necessary repairs. Verify that the problem is resolved.