1. Safety First:
* Disconnect the battery: This is crucial to prevent sparks near flammable fuel. Disconnect the negative (-) terminal first.
* Work in a well-ventilated area: Fuel fumes are dangerous.
* Wear safety glasses and gloves: Protect yourself from potential hazards.
2. Preparation:
* Consult a repair manual: A Chilton's or Haynes manual specific to your 1998 GMC Jimmy will provide detailed diagrams and instructions. This is highly recommended.
* Gather tools: You'll likely need: sockets (various sizes), wrenches, screwdrivers (Phillips and flathead), fuel line disconnect tools, a fuel pump pliers (or similar tool for clamping the fuel lines), a new fuel pump, possibly a new fuel filter, jack and jack stands (to safely lift the vehicle), and possibly a fuel pressure gauge (to check for proper pressure after installation).
3. Accessing the Fuel Pump:
* Lower the fuel tank: This is the most common method. You'll need to access the fuel pump through the access panel under the vehicle. This usually involves lowering the fuel tank, which requires disconnecting the fuel lines, electrical connectors, and tank straps. Your repair manual will guide you through this process, which includes safely relieving fuel pressure. *This is the most labor-intensive part.*
* Alternative (Less Common): Some models might allow access from inside the cargo area. Check your repair manual for this possibility. If this is feasible, it will significantly simplify the process.
4. Fuel Pump Replacement:
* Disconnect the fuel lines and electrical connectors: Carefully disconnect the fuel lines using the appropriate tools. Be prepared for some fuel spillage – have rags ready.
* Remove the fuel pump assembly: Once the lines and connectors are disconnected, you can remove the fuel pump assembly from the tank. This often involves unscrewing a retaining ring or unbolting a cover.
* Install the new fuel pump: Follow the reverse order of removal. Ensure the new fuel pump is securely seated.
* Reconnect fuel lines and electrical connectors: Double-check everything is properly connected.
5. Reassembly and Testing:
* Raise the fuel tank: Carefully raise the fuel tank back into its position. Secure all the straps.
* Reconnect the battery: Reconnect the positive (+) terminal last.
* Start the vehicle: Listen for any unusual noises from the fuel pump. Check for fuel leaks.
* Check fuel pressure (optional but recommended): Use a fuel pressure gauge to verify the fuel pressure is within the manufacturer's specifications.
Important Considerations:
* Fuel pressure: Always relieve pressure in the fuel system before disconnecting any fuel lines. This usually involves running the engine until it stalls, then turning the ignition key to the "on" position a few times to allow the pressure to bleed off. Your repair manual will give detailed instructions for your vehicle.
* Fuel tank safety: Fuel is highly flammable. Take all necessary precautions.
* Professional help: If you are not comfortable working on your vehicle, it is best to take it to a qualified mechanic.
This is a general overview. Always consult a repair manual specific to your 1998 GMC Jimmy for precise instructions and safety precautions. The manual will provide diagrams and details specific to your vehicle's model and configuration. Improperly performed fuel pump replacement can lead to serious problems.
