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Home >> Chevrolet >> 2018 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (Engine Controls And Fuel - 1.4L (LV7) - DTC P0351 To DTC P2544 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel Injector Diagnosis >> Fuel Injector Balance Test with Special Tool

Fuel Injector Balance Test with Special Tool

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE:
    • DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
    • Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
    • Before proceeding with this test review the User Manual CH-48027-5 for Safety Information and Instructions.
  1. Verify the correct fuel system pressure. Refer to Fuel System Diagnosis .
  2. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5 - 2.5 A position.
  3. Connect the EL-39021  to a Q17 Fuel Injector using the EN-44602  .
  4. Command the Fuel Pump Relay On and then Off three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 PSI) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
  5. Command the Fuel Pump Relay On one more time and energize the fuel injector by depressing the Push to Start Test button on the EL-39021  at the previously selected pressure.
  6. After the injector stops pulsing, select Min from the Display Mode on the CH-48027  and record the Min pressure.
    7. NOTE:

    New test results will not be recorded if the Min/Max results are not cleared after each injector is tested.

  7. Clear the Min/Max results on the CH-48027  .
  8. Select Normal from the Display Mode on the CH-48027  .
  9. Repeat steps 3 and 5 through 8 for each fuel injector.
  10. Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
  11. Obtain a pressure drop value for each fuel injector.
  12. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  13. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 PSI).
    • If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 PSI), replace the Q17 Fuel Injector.
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