GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Chevy MD Steel Tilt (W Model) 🢒 Engine 🢒 Engine Controls - 4.8L, 5.3L, and 6.0L 🢒 Fuel Tank Leak Test

Description

The fuel tank leak test is used to locate any fuel or vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected when the evaporative emission (EVAP) diagnostics complete one test cycle. The malfunction indicator lamp (MIL) will illuminate when a leak is detected.

Diagnostic Aids
    • Operate the vehicle under the condition of the customer concern. Under high temperature conditions, fuel vapors may increase to the point of EVAP canister vapor saturation. Fuel vapors would then be released into the atmosphere. Once the engine is running and EVAP purge is enabled, all fuel vapor release would be eliminated.
    • Movement of the EVAP pipes or fuel pipes may help find an intermittent condition.

Test Description

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

  1. This step tests for fuel leaks below the fuel tank fuel level.

    2.

  2. This step locates fuel vapors escaping above the fuel level in the fuel tank .

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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.
  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 you find fuel leaking from the fuel pipes?

Go to Step 7

Go to Step 4

4

  1. Remove the fuel tank filler cap.
  2. Install the GE-41415-50 Interrupted Thread Fuel Tank Cap Adapter or the J 41415-40 Fuel Tank Cap Adaptor.
  3. Install the fuel tank filler cap to the GE-41415-50 or J 41415-40 .
  4. Connect the J 41413-200 Evaporative Emission System Tester (EEST) to the fuel tank cap adaptor.
  5. Turn the nitrogen/smoke valve to nitrogen.
  6. Connect the nitrogen/smoke hose to the 0.5 mm (0.2 in) test orifice on the bottom-front of the J 41413-200 .
  7. Turn ON the ignition, with the engine OFF.
  8. Seal the evaporative emission (EVAP) system with a scan tool. Refer to Scan Tool Output Controls .
  9. Use the remote switch to activate the J 41413-200 and pressurize the fuel tank with nitrogen.

Did fuel leak from the fuel tank?

Go to Step 6

Go to Step 5

5

  1. Connect the J 41413-200 power supply clips to a known good 12-volt source.
  2. Turn ON the ignition, with the engine OFF.
  3. Command the EVAP canister vent solenoid valve closed with a scan tool.
  4. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE.
  5. Use the remote switch to introduce smoke into the EVAP system.
  6. Continue to introduce smoke into the fuel tank assembly for an additional 60 seconds.
  7. Inspect the fuel tank assembly for exiting smoke with the J 41413-SPT High Intensity White Light.

    8. Important: It may be necessary to partially lower the fuel tank. Refer to Fuel Tank Replacement .

  8. Continue to introduce smoke at 15-second intervals while observing the fuel tank assembly for leaks in any of the following locations:
    9. • The fuel tank, fill limiter vent valve, pressure relief valve, and rollover valves--Refer to Fuel Tank Replacement .
    • The fuel sender housing and fuel sender seal--Refer to Fuel Sender Assembly Replacement .
    • The fuel tank pressure (FTP) sensor seal--Refer to Fuel Tank Pressure Sensor Replacement .
    • The fuel fill pipe and hose--Refer to Filler Tube Replacement .

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