Introduction There have been isolated occurrences of excessive fuel leakage past the electronic unit injectors on some engines. Accelerated wear on the delivery valve results in an increased leak rate. For six cylinder engines, the fuel injection pump cannot generate enough fuel flow or volume in order to compensate for the leakoff rates above a critical value of 38 ml (1.3 oz) per 30 seconds of cranking at a speed of 150 rpm. For four cylinder engines, the critical value is 25 ml (0.85 oz) per 30 seconds of cranking at a speed of 150 rpm. If the engine turns over but the engine does not start, refer to Troubleshooting, "Engine Cranks but Will Not Start". Perform the following procedure when directed by Troubleshooting, "Engine Cranks but Will Not Start". The procedure will help to assess the amount of fuel pressure leakoff within the high-pressure fuel system. Note: The engine may start, but you may still have high leakoff within the high-pressure fuel system. NOTICE Do not perform any procedure in this Special Instruction until you read this information and you understand this information.
Note: If the electronic unit injectors are replaced, ensure that the valve bridge is seated in the correct position. Failure to carry out this procedure correctly may result in engine failure. For further information, refer to Engine News, SEBD9574, "Improved Valve Bridges" and Service Magazine, SEPD0975, "Improved Valve Bridges". Note: If applicable, a completed service report (form number 089479-00) must be included with the returned parts. ECM warranty report downloads, datalogs, and any special test results as directed by repair procedures are to be uploaded to SIMS. Checklists that are packaged with replacement parts are to be completed and packaged with parts being returned. Refer to Special Instruction, REHS7790, "Improved Fuel System Diagnostic Test Documentation for Certain C4.4 and C6.6 Engines" for additional diagnostic test documentation. Test Procedure for Measuring High Leakoff for the Electronic Unit Injectors NOTICE Before beginning any work on the fuel system, refer to Operation and Maintenance Manual, "General Hazard Information and High Pressure Fuel Lines" for safety information. Refer to Systems Operation, Testing and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of cleanliness that must be observed during ALL work on the fuel system. NOTICE After 30 seconds of cranking the engine, release the starter switch or button and wait 2 minutes to allow the starting motor to cool before attempting to start the engine again. Note: Caterpillar recommends that the procedure should be carried out without starting the engine. Table 1 Required Tools Tool Part Number Part Description Qty A 300-4988 Fuel Leakoff Kit 1 1. Ensure that the engine is shut down. Remove the banjo bolt that is located on the bottom of the fuel transfer pump. Retain the sealing washers for use in step 10.b.
Illustration 1 Typical example 2. Install Tooling (A) to the fuel transfer pump. Note: Tooling (A) will replace the banjo bolt that was removed in step 1. Do not substitute Tooling (A). Tooling (A) is specially designed for the test. 3. Install a clear plastic hose (1). Place the opposite end of the plastic hose into a suitable container that is clean. 4. Connect the electronic service tool to the diagnostic connector. 5. Disconnect the three harness connectors for the electronic unit injectors at the valve mechanism cover base to prevent starting the engine. 6. Perform a data log of the following parameters at a sample rate of 240 samples per minute. ECM Parameters Active Diagnostic Codes that are present Atmospheric Pressure Battery Voltage Delivered Fuel Volume Desired Engine Speed Desired Fuel Rail Pressure Diagnostic Clock Engine Coolant Temperature Engine Oil Pressure Derate of Engine Power
Engine Speed Fuel Rail Pressure Inlet Air Temperature Intake Manifold Pressure Requested Desired Engine Speed Fuel Volume for the Smoke Limit Fuel Volume for the Torque Limit Engine Load Factor 7. Start the data log. Crank the engine for 30 seconds. 8. End the data log. 9. Record the amount of fuel that has been collected in the container from the leakoff connector on the cylinder head. Conduct the test three times. Calculate the average of the three values. 10. Refer to step 10.a or step 10.b for the relevant values for your engine. a. For six cylinder engines, if more than 38 ml (1.3 oz) of fuel has been collected during the 30 second crank test, then there is high leakoff of the electronic unit injectors. For six cylinder engines, if less than 38 ml (1.3 oz) of fuel has been collected for the 30 second crank test, then there is not high leakoff of the electronic unit injectors. Refer to Troubleshooting, "Engine Cranks but Will Not Start" in order to diagnose the problem. b. For four cylinder engines, if more than 25 ml (0.85 oz) of fuel has been collected during the 30 second crank test, then there is high leakoff of the electronic unit injectors. For four cylinder engines, if less than 25 ml (0.85 oz) of fuel has been collected for the 30 second crank test, then there is not high leakoff of the electronic unit injectors. Refer to Troubleshooting, "Engine Cranks but Will Not Start" in order to diagnose the problem. 11. Remove Tooling (A). Install the banjo bolt and two new washers to the fuel transfer pump. 12. End of the test. If there is high leakage of the high-pressure fuel system, proceed to ""Measuring the Fuel Injection Pump Flow and High Leakoff for the Individual Electronic Unit Injector" ". Measuring the Fuel Injection Pump Flow and High Leakoff for the Individual Electronic Unit Injector This procedure provides a method to evaluate the internal leakage condition of the following components: Fuel injection pump Fuel pressure relief valve Electronic unit injectors The procedure provides a method to compare internal fuel leakage to a precision calibrated orifice.
Use the ""Test Kit Data Sheet" " for recording the test data. For an example of the test process calculations refer to ""Example Calculations Sheet" ". Use the checklist form provided with the replacement component to document the test results. Do not discard this form. A completed checklist is required to be included in the claim story. A completed checklist is to be included with any fuel injection system component returned for credit. Use the following procedure to aid in the diagnosing of the following conditions: The engine cranks but the engine does not start The fuel rail pressure is low There has been a low rail-pressure event The engine fuel injection system has excessive internal fuel pressure leakage Verify the following before continuing with this procedure: No fuel injection pump or electronic unit injector diagnostic trouble codes are active No external high-pressure leaks exist The cranking speed of the engine is at least 150 rpm Note: A battery booster is essential to maintain consistent cranking speed of at least 150 rpm for all fuel injection pump and electronic unit injector tests. The low-pressure fuel system is providing a minimum of 50 kpa (7 psi) of pressure to the fuel injection pump. Determine if the pressure in the fuel manifold (rail) during engine cranking is less than 22 MPa (3200 psi). This will assist when conducting the procedure in Troubleshooting, "Engine Cranks but Will Not Start". If troubleshooting for low rail-pressure event, first warm up the engine to improve the test results. If possible run at high speed and load to duplicate the low rail-pressure event conditions If it is not possible to put load on engine, run the "Fuel System Verification Test". This will increase the desired rail-pressure to help get the fuel injection pump and electronic unit injectors warm. Proceed with the test procedure while the fuel injection pump and electronic unit injectors are still warm. Required Parts Table 2 Required Parts for the Six Cylinder Engine Part Number Description Qty 362-9754 Test Kit 1 336-8174 Fuel Injection Line 1 336-8175 Fuel Injection Line 1 336-8176 Fuel Injection Line 1 336-8177 Fuel Injection Line 1
336-8178 Fuel Injection Line 1 336-8179 Fuel Injection Line 1 278-4138 Fuel System Protection Gp 1 Table 3 Required Parts for the Four Cylinder Engine Part Number Description Qty 362-9754 Test Kit 1 333-4732 Fuel Injection Line 1 333-4733 Fuel Injection Line 1 322-3745 Fuel Injection Line 1 322-3746 Fuel Injection Line 1 278-4138 Fuel System Protection Gp 1
Illustration 2 Typical example of 362-9754 Test kit (1) 356-2466 Case (2) 356-2470 Cylinder Collection (3) 362-9749 Orifice As - Discharge (4) 362-9753 Pin - Gauge (5) 362-9751 Plug As - Rail Test Procedure Electrical Shock Hazard. The electronic unit injectors use DC voltage. The ECM sends this voltage to the electronic unit injectors. Do not come in contact with the harness connector for the electronic unit injectors while the engine is operating. Failure to follow this instruction could result in personal injury or death. NOTICE Ensure that all adjustments and repairs that are carried out to the fuel system are performed by authorized personnel that have the correct training. Before beginning ANY work on the fuel system, refer to Operation and Maintenance Manual, "General Hazard Information and High Pressure Fuel Lines" for safety information. Refer to System Operation, Testing and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of cleanliness that must be observed during ALL work on the fuel system. Note: The pressures generated during this test are lower than those generated during normal operation. During this test, the fuel injection lines may be removed and reused when performing this procedure due to the lower pressures that are generated during the testing. This is the only condition where reuse of a fuel injection line is allowed. Note: All connections must be clean prior to assembly. Carefully inspect all connections, caps, and lines before each use. When not in use, caps, plugs, and orifice from the kit must be capped to prevent damage and debris entry. Use the gauge pin and an aerosol cleaner to ensure that the orifice is clean before performing this procedure. Measure the Pressure of the Fuel Injection Pump
This part of the process will set up the test components and determine if the fuel injection pump or the fuel pressure relief valve is defective for internal leakage. 1. Obtain the Test Kit Data Sheet. Use the Test Kit Data Sheet to record all test measurements. 2. Remove the fuel injection lines. Refer to Disassembly and Assembly, "Fuel Injection Lines - Remove" for the correct procedure. Illustration 3 Typical example 3. Connect one of the fuel injection lines (1) to the fuel manifold (rail) at cylinder number 1 fuel outlet connection. Connect the discharge orifice assembly (2) to the other end of the fuel injection line. Install the rail plug assemblies onto the fuel manifold (rail) for all remaining cylinder fuel outlet connections. Note: The collecting cylinder must be mounted at a position lower than the fuel manifold (rail) on the engine. 4. Insert the drain hose (3) from the outlet of the discharge orifice assembly into the collecting cylinder. Refer to illustration 3. 5. Disable all electronic unit injectors by disconnecting the injector harness connectors. Leave the electronic unit injectors disabled for the duration of the test.
Illustration 4 Typical example 6. Set 240 samples/minute for the electronic service tool graphing utility, "Data Log Recorder". 7. Record the fuel pressure in the fuel manifold (rail) and engine speed while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Illustration 5 Typical example (1) Pump test pressure measured at peak (2) Pump test engine speed measured when peak pressure occurs (3) 2 to 5 second typical for pressure to build (4) More than 5 seconds with pressure build required to capture peak 8. Determine the fuel pressure in the fuel manifold (rail) and the engine speed where the peak pressure was selected. Typically, pressure will start building after 2 to 5 sec and then there should be samples taken for 5 more seconds. Illustration 5 shows an example of selecting the peak pressure and corresponding speed. 9. Use the engine speed where the fuel pressure in the fuel manifold (rail) was selected from step 8 to determine the Minimum Cranking Pressure (MCP). Refer to table 4 for engine size and cranking rpm. Table 4 Fuel Injection Pump MCP (Minimum Cranking Pressure) Engine Speed (rpm) 150-174 175-199 200-224 225-249 250-274 275-300
Minimum Cranking Pressure for six cylinder engines 9391 kpa (1362 psi) 11935 kpa (1731 psi) 14713 kpa (2134 psi) 17713 kpa (2569 psi) 20926 kpa (3035 psi) 24352 kpa (3532 psi) Minimum Cranking Pressure for four cylinder engines 5550 kpa (805 psi) 6729 kpa (976 psi) 7970 kpa (1156 psi) 9253 kpa (1342 psi) 10583 kpa (1535 psi) 11956 kpa (1734 psi) 10. If the fuel pressure in the fuel manifold (rail) is less than the Minimum Cranking Pressure (MCP), inspect the Pressure Relief Valve (PRV) for leakage and retest. The PRV can be checked for leakage by inspecting the outlet of the valve for any fuel leakage. Refer to Special Instruction, REHS5712, "Inspecting the Fuel Rail High Pressure Relief Valve" for the correct procedure. 11. If the Pressure Relief Valve (PRV) does not leak, and fuel pressure in the fuel manifold (rail) displayed in the electronic service tool graph is less than the Minimum Cranking Pressure (MCP), remove, clean, and inspect the outlet check valves and retest. Refer to Special Instruction, REHS3751, "Servicing the Outlet Check Plugs on the Fuel Injection Pump" for the correct procedure. 12. Determine the new MCP based on the retest speed. If the fuel pressure in the fuel manifold (rail) displayed in the electronic service tool graph is still less than MCP, replace the fuel injection pump. Refer to Disassembly and Assembly for the correct procedures. 13. If the fuel pressure in the fuel manifold (rail) is greater than MCP, record the fuel pressure in the fuel manifold (rail) and peak pump rail pressure engine speed, which will be used for injector testing. proceed to ""Measure Electronic Unit Injector Number 2 Leakage" ". Note: Do not remove the test kit. The test kit is required for the remainder of this procedure. Measure Electronic Unit Injector Number 2 Leakage This part of the procedure will determine if individual electronic unit injectors are defective for internal leakage. Note: It is possible to measure the individual electronic unit injectors for leakage in any order. Use the order that is easiest for the engine in a particular application. Note: If the test speed for the electronic unit injector number 2 changes by more than 25 rpm from the measurement of Pump Test speed or drops below 150 rpm, the use of a battery booster is essential to maintain uniform speed with the pump test. This will improve the accuracy of test results. Make sure that there are no leaks during the test as the measurement will be invalid. Note: When 3 or more electronic unit injectors are found to have excessive leakage, stop the test. Record the results of the leak rate for each electronic unit injector tested. Then replace all electronic unit injectors. Refer to Disassembly and Assembly for the correct procedure.
Illustration 6 Typical example 1. Install existing fuel injection line for number 2 cylinder. Refer to Disassembly and Assembly, "Fuel Injection Lines - Install" for the correct procedure. Refer to illustration 6. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Illustration 7 Typical example (1) Injector test pressure measured at peak (2) Injector test engine speed measured when peak pressure occurs (3) 2 to 5 second typical for pressure to build (4) More than 5 seconds with pressure build required to capture peak 3. Determine the injector number 2 test rail pressure and the injector number 2 test engine speed (where the peak pressure was selected). Typically, pressure will start building after 2 to 5 sec and then there should be sampling for 5 more seconds. Illustration 7 shows an example of selecting the peak pressure and corresponding speed. 4. Calculate the speed change of the injector number 2 test as follows: Injector number 2 test speed change equals injector number 2 test engine speed minus pump test engine speed. 5. Determine injector number 2 pressure correction using the injector number 2 test speed change and table 5. This will correct for pressure change as speed changes.
Table 5 Injector Pressure Correction Based on Speed Change Engine speed change (rpm) 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Six-cylinder pressure correction 283 kpa (41 psi) 896 kpa (130 psi) 1455 kpa (211 psi) 2013 kpa (292 psi) 2572 kpa (373 psi) 3130 kpa (454 psi) 3689 kpa (535 psi) Four-cylinder pressure correction 159 kpa (23 psi) 510 kpa (74 psi) 834 kpa (121 psi) 1151 kpa (167 psi) 1469 kpa (213 psi) 1793 kpa (260 psi) 2110 kpa (306 psi) 6. If injector number 2 test engine speed is lower than pump test engine speed, then correct the injector number 2 pressure by adding the correction as follows: Injector number 2 corrected pressure equals injector number 2 test pressure plus injector number 2 pressure correction. 7. If injector number 2 test engine speed is higher than pump test engine speed (as can happen when a battery booster is used) then correct the injector number 2 test pressure by subtracting the pressure correction as follows: Injector number 2 corrected pressure equals injector number 2 test pressure minus injector number 2 pressure correction. 8. Calculate injector number 2 leakage ratio as follows: Injector number 2 leakage ratio equals injector number 2 corrected pressure divided by pump test Rail pressure. If the Injector number 2 leakage ratio is less than 0.85, the injector needs to be replaced, if the injector leakage is greater than 0.85 the injector is ok. Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 3 Leakage" ". Measure Electronic Unit Injector Number 3 Leakage
Illustration 8 Typical example 1. Remove the cap from cylinder number 3 and reconnect the existing fuel line. Refer to illustration 8. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid. 3. Determine the injector number 3 test rail pressure and the injector number 3 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 4. Calculate the speed change of the injector number 3. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 5. Determine injector number 3 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 6. Calculate injector number 3 leakage ratio. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 5 Leakage (if applicable)" ". Measure Electronic Unit Injector Number 5 Leakage (if applicable)
Illustration 9 Typical example 1. Remove the cap from cylinder number 5 and reconnect the existing fuel line. Refer to illustration 9. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid. 3. Determine the injector number 5 test rail pressure and the injector number 5 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 4. Calculate the speed change of the injector number 5. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 5. Determine injector number 5 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 6. Calculate injector number 5 leakage ratio. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 6 Leakage (if applicable)" ". Measure Electronic Unit Injector Number 6 Leakage (if applicable)
Illustration 10 Typical example 1. Remove the cap from cylinder number 6 and reconnect the existing fuel line. Refer to illustration 10. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid. 3. Determine the injector number 6 test rail pressure and the injector number 6 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 4. Calculate the speed change of the injector number 6. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 5. Determine injector number 6 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 6. Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 4 Leakage" ". Measure Electronic Unit Injector Number 4 Leakage
Illustration 11 Typical example 1. Remove the cap from cylinder number 4 and reconnect the existing fuel line. Refer to illustration 11. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid. 3. Determine the injector number 4 test rail pressure and the injector number 4 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 4. Calculate the speed change of the injector number 4. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 5. Determine injector number 4 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 6. Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 1 Leakage" ". Measure Electronic Unit Injector Number 1 Leakage
Illustration 12 Typical example 1. If necessary, remove the discharge orifice assembly from the outlet connection for number 1 cylinder. If necessary, remove the cap from cylinder number 1 and reconnect the existing fuel line. Refer to illustration 12. 2. Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds. Note: Make sure that there are no connection leaks during this test as the measurement will be invalid. 3. Determine the injector number 1 test rail pressure and the injector number 1 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 4. Calculate the speed change of the injector number 1. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 5. Determine injector number 1 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 6. Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ". 7. Remove components of 362-9754 Test Kit from the engine. Replace any fuel injection lines that were removed during the procedures. Refer to Disassembly and Assembly for the correct procedures. 8. Reconnect the electronic unit injector harness connectors. Test Kit Data Sheet Table 6 Fuel Injection Pump Tests Pump Test Rail Pressure Pump Test Engine Speed Minimum Cranking Pressure (MCP) Service
From Pump Test Datalog From Pump Test Datalog where peak rail pressure occurs Use speed and table 4 Pump Test 1 Pump Test 2 (after PRV service) Pump Test 3 (after outlet check valve clean) If peak pressure less than MCP inspect PRV If peak pressure less than MCP inspect outlet check valves If peak pressure less than MCP replace fuel injection pump Injector Test Rail Pressure Injector Test Engine Speed Injector Test Engine Speed Change Injector Test Pressure Correction Injector Corrected/Pump Pressure Ratio Electronic Unit Injector Tests From Injector Test Datalog From Injector Test Datalog where peak rail pressure occurs Last Pump Test Speed subtract Injector Test Speed Using speed change and table 5 Corrected Injector Pressure divided by Latest Pump Pressure Service Injector Number 2 Test If less than 0.85 replace Injector 2 Injector Number 3 Test If less than 0.85 replace Injector 3 Injector Number 5 Test If less than 0.85 replace Injector 5 Injector Number 6 Test If less than 0.85 replace Injector 6 Injector Number 4 Test If less than 0.85 replace Injector 4
Injector Number 1 Test If less than 0.85 replace Injector 1 Example Calculations Sheet Fuel Injection Pump Test Illustration 13 Typical example of pump pressure and speed measurement Pump Test Rail Pressure (1) is 14148 kpa (2052 psi). Pump Test Engine Speed (2) is 162 rpm. With Pump Test Engine Speed of 162 rpm, Minimum Cranking Pressure (MCP) from table 4 is 9391 kpa (1362 psi).
Pump Test Rail Pressure of 14148 kpa (2052 psi) is larger than MCP of 9391 kpa (1362 psi), so fuel injection pump is OK. Electronic Unit Injector Test Illustration 14 Typical example of injector Test pressure and speed measurement Injector Rail Pressure (1) is 10721 kpa (1555 psi). Injector Test Engine Speed (2) is 144 rpm. Injector Engine Speed Change is 162 minus 144 equals 18 rpm. Injector Pressure Correction from table 5 is 2013 kpa (292 psi). Speed is higher than pump test speed so add the correction: Injector Corrected Pressure equals 10721 kpa (1555 psi) add 2013 kpa (292 psi) equals 12735 kpa (1847 psi). Injector Leakage Ratio is 1847 divided by 2052 equals 0.90. Injector Leakage Ratio of 0.90 is larger than injector ratio threshold of 0.85, so the injector leakage is OK.