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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 104 (Engine Controls And Fuel - 6.0L (L96 LC8) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> Fuel Injector Diagnosis >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • The resistance test must be performed at the Fuel Injector or mis-diagnosis will occur.
  • The DMM and test leads must be calibrated to 0 Ω in order to prevent mis-diagnosis.

Verify the resistance of each fuel injector:

Fuel Injector Coil Test

  1. Ignition ON, verify the scan tool ECT temperature is between 10 - 32°C (50 - 90°F).
    • If not within the specified range 
    1. Measure and record the resistance of each Q17 Fuel Injector with a DMM.
    2. Subtract the lowest resistance value from the highest resistance value.
    3. Verify the difference between the lowest value and the highest value is 3 Ω or less.
      • If the difference is greater than 3 Ω
      1. Add all of the Q17 Fuel Injector resistance values to obtain a total resistance value.
      2. Divide the total resistance by the number of fuel injectors to obtain an average resistance value.
      3. Subtract the lowest individual fuel injector resistance value from the average resistance value
      4. Subtract the average resistance value from the highest individual fuel injector resistance value.
      5. Replace the Q17 Fuel Injector that displays the greatest difference above or below the average value.
    • Go to next step: If within the specified range 
  2. Test for 11 - 14 Ω between terminal A and terminal B of each Q17 Fuel Injector.
    • If not between 11 - 14 Ω 

      Replace the Q17 Fuel Injector.

    • Go to next step: If between 11 - 14 Ω 
  3. Verify infinite resistance between each terminal at the Q17 Fuel Injector and the fuel injector housing/case.
    • If less than infinite resistance 

      Replace the Q17 Fuel Injector

    • Go to next step: If infinite resistance 
  4. Perform the Fuel Injector Balance Test - Fuel Pressure Test.

Fuel Injector Balance Test - Fuel Pressure Test

  1. Ignition OFF, relieve the fuel pressure, refer to Fuel Pressure Relief . Install the CH - 37287 - 1A  Fuel Pressure Gauge Adapter and CH-48027  Digital Fuel Pressure Gauge to the fuel rail side of the adaptor. Refer to Fuel Pressure Gauge Installation and Removal .
  2. Ignition ON, engine OFF, command the Fuel Pump Enable On several times with a scan tool.
  3. Verify the Fuel Pressure is between 345-551 kPa (50-80 PSI) with the fuel pump running.
    • Go to next step: If between 345-551 kPa (50-80 PSI) 
    4. NOTE:

    The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.

  4. Verify that the Fuel Pressure stabilizes to 345-448 kPa (50-65 PSI) after the fuel pump is turned off.
    • Go to next step: If the fuel pressure stabilizes to 345-448 kPa (50-65 PSI) 
  5. Verify the Fuel Pressure Sensor parameter does not decrease greater than 34 kPa (5 PSI) in 1 min.
    • Go to next step: If the fuel pressure does not decrease greater than 34 kPa (5 PSI) 
  6. Perform the appropriate Fuel Injector Balance Test.
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