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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1446 (Engine Control System - 4.2L - Troubleshooting & Diagnosis) >> Diagnosis Information & Procedures >> Fuel Tank Leak Test >> Test Description

Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. 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. 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 - Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
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 in General Information.
  2. Inspect the fuel tank and the 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 Adapter or the GE-41415-50 Interrupted Thread Cap Adapter.
  3. Test for a fuel tank leak referring to the J 41413-210 Operation Manual.
    4. IMPORTANT: If the floating indicator registers any flow after stabilizing, a leak is evident.
  4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  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.
    2. IMPORTANT: It may be necessary to partially lower the fuel tank. Refer to Fuel Tank Replacement (TrailBlazer, Envoy, Bravada, Rainier)Fuel Tank Replacement (TrailBlazer EXT, Envoy XL, Envoy XUV) .
  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 (TrailBlazer, Envoy, Bravada, Rainier)Fuel Tank Replacement (TrailBlazer EXT, Envoy XL, Envoy XUV) .
Did you complete the replacement?		 Go to Step 8  -
7 Replace the leaking fuel pipe. Refer to Fuel Hoses/Pipes Replacement - Filter to Tank .
Did you complete the replacement?		 Go to Step 8  -
8 Operate the system under the condition of the customer concern in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
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