1. Safety First:
* Disconnect the negative battery terminal. This is paramount to prevent accidents.
* Release fuel system pressure. This is usually done by starting the vehicle and letting it run until it stalls (after several attempts, the pressure should be released). Some vehicles have a specific pressure release valve. Check your repair manual.
* Work in a well-ventilated area. Fuel vapors are highly flammable.
* Wear safety glasses and gloves.
2. Accessing the Fuel Pump:
* Lower the fuel tank: This is usually the most challenging part. You'll likely need to:
* Raise the vehicle securely on jack stands. Never work under a vehicle supported only by a jack.
* Remove the access panel/cover: This might be located under the vehicle, often near the rear axle.
* Disconnect the fuel lines: You'll need fuel line disconnect tools to safely separate the lines from the fuel pump. Have rags ready to soak up any spilled fuel. Mark the lines to ensure correct reassembly.
* Disconnect the electrical connector: This connects the fuel pump to the vehicle's electrical system.
* Disconnect the fuel tank sending unit: This is the unit that measures the fuel level. Be careful not to damage it.
* Lower the fuel tank: Many methods exist depending on your vehicle. You may need to disconnect straps or supports holding the tank. Be prepared for the tank to be heavy when it's full or partially full; consider draining some fuel beforehand if feasible.
3. Replacing the Fuel Pump:
* Once the tank is lowered, you'll see the fuel pump assembly. It's usually a unit that includes the pump, sending unit, and filter.
* Carefully remove the retaining ring or bolts securing the pump assembly to the tank.
* Remove the old fuel pump assembly.
* Install the new fuel pump assembly. Make sure it's correctly seated and secured.
* Reconnect everything in reverse order. Be sure the connections are tight and secure. Pay particular attention to the fuel lines.
4. Reassembly:
* Raise the fuel tank back into place.
* Reconnect all the fuel lines, electrical connectors, and fuel sending unit.
* Secure the tank.
* Reconnect the negative battery terminal.
5. Testing:
* Start the vehicle and check for leaks. If you see any fuel leaks, immediately stop and re-check your connections.
* Verify the fuel pressure. This usually requires a fuel pressure gauge.
* Check the vehicle's performance.
Important Considerations:
* Repair manual: A repair manual specific to your 1996 GMC Yukon is invaluable. It will provide detailed instructions, diagrams, torque specifications, and safety precautions.
* Fuel pump: Ensure you purchase the correct fuel pump for your vehicle's engine.
* Tools: You'll need various tools, including wrenches, sockets, screwdrivers, fuel line disconnect tools, and potentially a fuel pump removal tool.
* Assistance: This job is easier with a helper, especially when handling the heavy fuel tank.
This is a general guide, and the exact procedure may vary slightly depending on your specific Yukon model. If you are not comfortable performing this repair yourself, take your vehicle to a qualified mechanic. Improperly installing a fuel pump can lead to serious problems, including fire or fuel leaks.
