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Home >> Hummer >> 2005 >> H2 4D Utility Pickup >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Troubleshooting >> Troubleshooting >> Fuel Tank Leak Test >> Test Description
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Test Description

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

  1. 4:  This step tests for fuel leaks below the fuel tank fuel level.
  2. 5:  This step tests for fuel vapors escaping above the fuel level in the fuel tank.
Fuel Tank Leak Test

Step Action Yes No
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2
CAUTION: Gasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Inspect the fuel tank and fuel pipes for damage or external leaks.
Did you find fuel leaking from the fuel tank?		 Go to Step 6  Go to Step 3 
3
  1. Turn ON the ignition, with the engine OFF.
  2. Command the fuel pump relay ON with a scan tool.
  3. Inspect for fuel leaking from the fuel pipes.
Did fuel leak from the fuel pipes?		 Go to Step 7  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Install the J 41413-200  Evaporative Emissions System Tester (EEST) and the J 41415-40 Fuel Tank Cap Adaptor or the GE-41415-50 Interrupted Thread Fuel Tank Cap Adapter. See Special Tools .
    3. IMPORTANT: If the floating indicator registers any flow after stabilizing, a leak is evident.
  3. Test for a fuel tank leak referring to the J 41413-210 Operation Manual.
  4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  5. Inspect for a fuel leak while the system is under pressure.
Did fuel leak from the fuel tank?		 Go to Step 6  Go to Step 5 
5 
  1. Using the J 41413-200  and the J 41413-210 Operation Manual, introduce smoke into the evaporative emission (EVAP) system. See Special Tools .
    2. IMPORTANT: It may be necessary to partially lower the fuel tank. Refer to Fuel Tank Replacement .
  2. Inspect for leaks in any of the following locations:
Did you find and correct the condition?		 Go to Step 8  Go to Diagnostic Aids
6 Replace the fuel tank. Refer to Fuel Tank Replacement .
Did you complete the repair?		 Go to Step 8  -
7 Replace the leaking fuel pipe. Refer to Fuel Hose/Pipes Assembly Replacement .
Did you complete the replacement?		 Go to Step 8  -
8 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
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