Fuel system check

Warning: Gasoline is extremely flammable, so take extra precautions when you work on any part of the fuel system. Don’t smoke or allow open flames or bare light bulbs near the work area, and don’t work in a garage where a gas-type appliance (such as a water heater or clothes dryer) is present. Since gasoline is carcinogenic, wear fuel-resistant gloves when there’s a possibility of being exposed to fuel, and, if you spill any fuel on your skin, rinse it off immediately with soap and water. Mop up any spills immediately and do not store fuel-soaked rags where they could ignite. When you perform any kind of work on the fuel system, wear safety glasses and have a Class B type fire extinguisher on hand. The fuel system is under constant pressure, so, before any lines are disconnected, the fuel system pressure must be relieved (see Fuel and exhaust systems).

Note: These vehicles are not equipped with fuel filters. A filter is integral with the fuel pump/fuel level sensor module and requires no maintenance.

1. If you smell gasoline while driving or after the vehicle has been sitting in the sun, inspect the fuel system immediately.

2. Remove the gas filler cap and inspect if for damage and corrosion. The gasket should have an unbroken sealing imprint. If the gasket is damaged or corroded, install a new cap.

3. Inspect the fuel feed and return lines for cracks. Make sure that the connections between the fuel lines and the fuel injection system are tight.

Warning: Your vehicle is fuel injected, so you must relieve the fuel system pressure before servicing fuel system components. The fuel system pressure relief procedure is outlined in Chapter Fuel and exhaust systems.

4. If the fuel injectors are visible, look for signs of fuel leakage (wet spots) around any of the injectors, they may need new 0-rings (see Fuel and exhaust systems).

5. Since some components of the fuel system — the fuel tank and part of the fuel feed and return lines, for example — are underneath the vehicle, they can be inspected more easily with the vehicle raised on a hoist. If that’s not possible, raise the vehicle and support it on jack stands.

6. With the vehicle raised and safely sup- ported, inspect the gas tank and filler neck for punctures, cracks and other damage. The connection between the filler neck and the tank is particularly critical. Sometimes a rubber filler neck will leak because of loose clamps or deteriorated rubber. Inspect all fuel tank mounting brackets and straps to be sure that the tank is securely attached to the vehicle.

Warning: Do not, under any circumstances, to/ to repair a fuel tank (except rubber components). A welding torch or any open flame can easily cause fuel vapors inside the tank to explode.

7. Carefully check all rubber hoses and metal lines leading away from the fuel tank. Check for loose connections, deteriorated hoses, crimped lines and other damage. Repair or replace damaged sections as necessary (see Fuel and exhaust systems).

8. The evaporative emissions control system can also be a source of fuel odors. The function of the system is to store fuel vapors from the fuel tank in a charcoal canister until they can be routed to the intake manifold where they mix with incoming air before being burned in the combustion chambers.

9. The most common symptom of a faulty evaporative emissions system is a strong odor of fuel. If a fuel odor has been detected, and you have already checked the areas described above, check the charcoal canister, located under the rear of the vehicle, and the hoses connected to it (see illustration).

18.9 Check the evaporative emissions system canister and its lines for damage

Chevrolet Silverado  _ Check the evaporative emissions system canister and its lines for damage

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