Here's a general outline; specifics may vary slightly depending on your exact Jimmy model (engine size, trim level etc.). Consult a repair manual specific to your 1998 GMC Jimmy for detailed instructions and diagrams. This is crucial for accuracy and safety.
1. Preparation:
* Safety First: Disconnect the negative battery cable.
* Gather Tools: You'll need jack stands, jack, wrenches (various sizes), sockets, fuel line disconnect tools, a fuel pump pliers (or similar tool to compress the retaining rings on the fuel lines), possibly a fuel pressure gauge, safety glasses, gloves, rags, and a new fuel pump assembly (ensure it's the correct one for your vehicle).
* Drain the Fuel Tank (Recommended): This significantly reduces the risk of fuel spillage. You can siphon the fuel out using a siphon pump.
* Locate the Fuel Pump: It's usually located inside the fuel tank, accessed through the vehicle's undercarriage.
2. Accessing the Fuel Pump:
* Raise the Vehicle: Safely raise the rear of the Jimmy using a jack and secure it with jack stands. Never work under a vehicle supported only by a jack.
* Remove Access Panel: Locate the access panel to the fuel tank. This may involve removing the spare tire and/or some plastic underbody panels.
* Disconnect Fuel Lines and Electrical Connectors: Carefully disconnect the fuel lines. Use the appropriate fuel line disconnect tools to avoid damaging the lines or spilling fuel. There are usually two lines: supply and return. Also disconnect the electrical connectors to the fuel pump. Label everything clearly to avoid confusion during reassembly.
* Remove Fuel Pump Assembly: This usually involves removing a retaining ring (possibly with a fuel pump pliers) and then carefully lifting the fuel pump assembly out of the tank. There may be a retaining strap or other fasteners to remove.
3. Replacing the Fuel Pump:
* Inspect the Old Pump: Note any issues with the old pump for diagnostic purposes.
* Install New Fuel Pump: Install the new fuel pump assembly into the tank, ensuring it's seated correctly. Reattach the retaining ring or other fasteners.
* Reconnect Fuel Lines and Electrical Connectors: Carefully reconnect the fuel lines and electrical connectors, ensuring they are securely fastened. Double-check all connections.
4. Reassembly and Testing:
* Lower the Vehicle: Carefully lower the vehicle from the jack stands.
* Reinstall Access Panel: Replace the access panel and any other removed components.
* Reconnect Battery: Reconnect the negative battery cable.
* Prime the Fuel System (Important): Some vehicles require you to prime the fuel system after replacing the pump. This might involve turning the ignition key to the "on" position several times (without starting the engine) to build fuel pressure. Check your repair manual for your car's specific instructions.
* Test the Vehicle: Start the vehicle and check for leaks. Listen for unusual noises from the fuel pump. Let the vehicle run for a while to ensure the pump is functioning correctly. Take it for a short test drive.
Disclaimer: This is a general guide and may not be entirely accurate for your specific vehicle. Always consult a repair manual specific to your 1998 GMC Jimmy for precise instructions and safety precautions. If you are not comfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic. Improper fuel system repair can be dangerous.
