Service Manual Table of Contents & Testing Guide

Table of Contents

1. General
2. Engines
3. Fuel System
4. Hydraulics
5. Steering
6. Power Train
7. Brakes
8. Electrical

Manual Extract: Testing for Leakage and Correct Opening Pressure

This section provides detailed instructions for testing the leakage and verifying the correct opening pressure of a nozzle valve.

Testing Instructions

• Partially Open the Gauge Valve: Turn the valve approximately one full turn. It is not required to fully open the gauge valve.
• Operate the Hand Lever: Slowly operate the hand lever to increase the pressure until the nozzle valve opens and fuel is sprayed. Note the opening pressure displayed on the pressure gauge.
• Verify Opening Pressure: If the observed opening pressure is correct, resetting is not required.
• Check Initial Pressure Drop: Increase the pressure again until the nozzle valve opens. At the moment of opening, observe the sharp pressure drop, which should not exceed 300 pounds. If excessive, the nozzle valve might be sticking; clean the nozzle assembly.
• Observe Pressure Stabilization: Allow pressure to decrease, and then slowly increase it again to hold between 1850 to 1900 pounds. Inspect the nozzle; it should remain dry at about 100 pounds below the recommended opening pressure.
• Check for Leaks: If fuel drops appear at the nozzle valve projection, the valve is leaking.
• Monitor Leak-Off Connection: While checking pressure and leakage, note the fuel amount exiting from the leak-off connection. Only a minimal amount is needed for lubrication. Excessive overflow indicates the injector requires servicing.

Note: To assess what qualifies as excess flow from the leak-off connection, compare with a new injector assembly using a test stand.