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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 487 (ENGINE CONTROLS - 6.0L - ALTERNATIVE FUELS (TROUBLESHOOTING))TROUBLESHOOTINGFUEL INJECTOR BALANCE TEST WITH TECH 2TEST DESCRIPTION
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

Test Description

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Test Description
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  The fuel pressure should be within the specified range. Refer to Fuel System Diagnosis  if the fuel pressure is not within the specified range.
  2. 4:  The fuel pressure should reach a steady value. Refer to Fuel System Diagnosis  if the fuel pressure does not stabilize.
  3. 5:  If the pressure drop value for each fuel injector is within 14 kPa (2.0 psi) of the average pressure drop value, the fuel injectors are flowing properly. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading.
Fuel Injector Balance Test Procedure

Step Action Values Yes No
1 Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Alternative Fuels (Engine Controls)
2 Did you perform the Fuel Injector Coil Test? - Go to Step 3  Go to Fuel Injector Coil Test 
3 
  1. Start and idle the engine.
  2. Observe the fuel rail pressure sensor parameter with a scan tool.
Is the fuel pressure within the specified range?		 275-345 kPa (40-50 psi Go to Step 4  Go to Fuel System Diagnosis 
4 
  1. Turn OFF the ignition.
  2. Turn ON the ignition, with the engine OFF.
  3. Monitor the fuel rail pressure sensor parameter with a scan tool.
Does the fuel rail pressure remain constant?		 - Go to Step 5  Go to Fuel System Diagnosis 
5 
NOTE: Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding.
  1. With a scan tool, select the Fuel Injector Balance Test function, within the Special Functions menu.
  2. Select an injector to be tested.
  3. Press Enter. This will prime the fuel system.
  4. Record the fuel pressure indicated by the fuel pressure sensor after the fuel rail pressure stabilizes. This is the 1st pressure reading.
    5. IMPORTANT: Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value.
  5. Energize the fuel injector by depressing the Pulse Injector button on the scan tool. This will energize the injector and decrease the fuel pressure.
  6. Record the fuel pressure indicated by the fuel rail pressure sensor after the fuel injector has stopped pulsing. This is the 2nd pressure reading.
  7. Press Enter again to bring you back to the Select Injector screen.
  8. Repeat for each fuel injector.
  9. Subtract the 2nd pressure reading from the 1st pressure reading for one fuel injector. The result is the pressure drop value.
  10. Obtain a pressure drop value for each fuel injector.
  11. Add all of the individual pressure drop values. This is the total pressure drop.
  12. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop.
Does any fuel injector have a pressure drop value that is either higher than the average pressure drop or lower than the average pressure drop by the specified value?		 14 kPa (2.0 psi) Go to Step 6  Go to Symptoms - Engine Controls 
6 Replace the affected fuel injector. Refer to Fuel Injector Replacement .
Did you complete the replacement?		 - Go to Step 7  -
7 Operate the vehicle in order to verify the repair.
Does a driveability condition still exist?		 - Go to Symptoms - Engine Controls  System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.