FUEL INJECTION PUMP GROUP 4N2637 - Caterpillar

Blocked Cylinder Tests (Chart C)
If the System Tests and Pump Test give an indication of leakage in the control valves and/or cylinders that is not acceptable, do the Blocked Cylinder Tests.Blocking Plate Assemblies or Caps and Plugs can be put in each of the cylinder lines. For best accuracy, do these tests with the oil temperature approximately 150° F (near the oil temperature for the System Tests and Pump Test).
Install the safety link. Lower all implements to the ground. Move the steering wheel from RIGHT TURN to LEFT TURN several times to release any pressure oil in the cylinder lines. All pressure in the lines must be released or injury to personnel and damage to equipment can result while loosening the lines to install or remove the plate assemblies.
All Cylinders Blocked
1. Put control levers in HOLD position.2. Open the manual load valve fully.3. Start the diesel engine. Test 26: System Oil Temperature1. Turn the steering wheel to the RIGHT TURN position.2. Run the engine at any rpm with the system pressure at 0 to 100 psi.3. Write down the oil temperature. Test 27 and 28: Leakage RatesThese two tests are similar. Do the tests as follows: 1. With the manual load valve fully open, turn the steering wheel to the RIGHT TURN position.2. Run the engine at test rpm.3. Slowly close the manual load valve to get 1000 psi pressure.4. Write down the flow rate (gpm).5. Do this procedure again in the LEFT TURN position. Test 33: System Oil Temperature1. Turn the steering wheel to the RIGHT TURN position.2. Run the engine at any rpm with the system pressure at 0 to 100 psi.3. Write down the oil temperature.Find the leakage rate of the cylinders and the leakage rate of the control valves. Use the test information from the System Tests, Pump Test and Blocked Cylinder Tests.Example: Find the leakage rates in the RIGHT TURN position.Test 15: flow rate of the pump only.Test 27: flow rate of pump and control valve.Test 4: flow rate of pump, control valve and cylinders.The system components tested in Tests 15 and 27 are the same except for the control valve. Then the difference in flow rates must be the leakage in the control valve (take the test information for Test 27 away from the test information for Test 15).The system components tested in Tests 27 and 4 are the same except for the cylinders. Then the difference in flow rates must be the leakage in the cylinders (take the test information for Test 4 away from the test information for Test 27).Make a comparison of the test data with the data on Chart C for the specific machine under test. The information on Chart C is the maximum for best performance.Troubleshooting
PROBLEM: Tests 27 and 28 give an indication of leakage in one or more of the cylinders. PROBABLE REASON:A. Leakage in only one of the cylinders.B. Leakage in both cylinders. RECOMMENDATION FOR ACTION:Do the Blocked Cylinder Test for cylinders on the right