Fuel System Cleaning. Cadillac Concours 1997

For 1990-2009 cars

### Tools Required

• | J 34730-1A , Fuel Pressure Gauge

• | J 37088-A , Fuel Line Quick-Connect Separator Tool Set

• | J 39765 , Fuel Sender Lock Nut Wrench

### Removal Procedure

Important: The following procedure covers disassembly and inspection of the complete fuel supply system. If the fuel system is contaminated, it can be cleaned. The extent of fuel system contamination can usually be determined during disassembly.

1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .
2. Remove the in-line fuel filter. Refer to In-Line Fuel Filter Replacement .

Important: If filter is plugged or contaminated, replace it after cleaning fuel pipes.

3. Inspect the in-line fuel filter for contamination.
4. Drain fuel tank. Refer to Fuel Tank Replacement (Draining) .
5. Remove fuel tank. Refer to Fuel Tank Replacement .
6. Locate the tank in a suitable work area away from heat, flame, or other source of ignition.
7. Remove the modular fuel sender assembly from the fuel tank. Refer to Fuel Sender Assembly Replacement .
8. Inspect the fuel sender strainer. If the strainer is contaminated, the strainer must be replaced and the fuel tank should be cleaned.
9. Inspect the fuel pump inlet for dirt and debris. If found, the fuel sender should be replaced.
10. Flush fuel tank with running hot water for at least five minutes.
11. Pour the water out of fuel sender assembly opening.
12. Rock the tank to be sure that removal of water from tank is complete.

Notice: Do not attempt to straighten any kinked nylon fuel lines. Replace any kinked nylon fuel feed or return pipes in order to prevent damage to the vehicle.

13. Remove the quick-connect fittings at the engine compartment fuel feed (2) and return pipes (3).
14. Remove the EVAP (1) pipe if necessary.

Caution: Wear safety glasses when using compressed air in order to prevent eye injury.

15. Grasp both ends of the fuel feed pipe connection and twist ¼ turn in each direction to loosen any dirt in the quick connect fittings.
16. Blow out dirt from the quick connect fittings, using compressed air.
17. Insert tool J 37088-A into female connector, then push inward to release the male connector.
18. Pull the connection apart.
19. Repeat step 14 through 17 for the other fitting.

Notice: Use an emery cloth in order to remove rust or burrs from the fuel pipe. Use a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface.

20. Apply air pressure to fuel pipes in the opposite direction from normal fuel flow.
21. Wipe off male pipe ends. Inspect all connectors for dirt and burrs, using a clean shop towel.
22. Clean the components/assemblies as required.
23. Replace the components/assemblies as required.

### Installation Procedure

Caution: Always apply a few drops of clean engine oil to the male pipe ends before connecting the fuel pipe fittings in order to reduce the risk of fire and personal injury. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

1. Apply a few drops of clean engine oil to the male tube ends of the fuel feed and return engine pipes.
2. Connect the fuel feed and fuel return pipe quick-connect fittings
3. Push connectors together to cause the retaining tabs/fingers to snap into place.
4. Once installed, pull on both ends of each connection to make sure they are secure.
5. Install fuel sender assembly into the fuel tank. Refer to Fuel Sender Assembly Replacement .
6. Install the fuel filter. Refer to In-Line Fuel Filter Replacement .
7. Install fuel tank (4). Refer to Fuel Tank Replacement .
8. Install the negative battery cable. Refer to Engine Electrical.

8.1. | Turn ignition switch to ON for 2 seconds.

8.2. | Turn the ignition switch to OFF for 5 seconds.

8.3. | Turn the ignition switch ON

8.4. | Check for fuel leaks.