Here's a general outline. Specifics may vary slightly depending on your S10's engine and trim level. Consult a repair manual specific to your 1991 Chevy S10 for detailed instructions and diagrams. A Haynes or Chilton manual is a great investment.
1. Preparation:
* Gather Tools: You'll need a socket wrench set (metric), screwdrivers (Phillips and flathead), pliers, fuel line disconnect tools, safety glasses, gloves, rags, jack stands, and possibly a fuel pump pressure gauge.
* Safety Precautions: Disconnect the negative battery terminal. Allow the fuel system to depressurize (let the engine run until it stalls if possible, or relieve pressure manually - consult your repair manual for the specific procedure).
* Locate the Fuel Pump: It's typically located inside the fuel tank, accessed from underneath the truck.
* Drain Fuel: If possible, drain as much fuel from the tank as safely as possible to reduce the amount of fuel you'll be working near.
2. Accessing the Fuel Pump:
* Lower the Tank (Usually Necessary): This usually involves lowering the fuel tank. This requires supporting the tank safely with jack stands. Consult your repair manual for the correct procedure. You may need to disconnect the fuel lines, electrical connector, and tank straps.
* Access Panel (Less Common): Some S10s might have an access panel under the bed, but this is less common.
3. Removing the Old Fuel Pump:
* Disconnect Electrical Connector: Carefully disconnect the electrical connector from the fuel pump.
* Disconnect Fuel Lines: Use fuel line disconnect tools to carefully separate the fuel lines from the pump. Have rags ready to absorb any spilled fuel.
* Remove the Pump Assembly: This usually involves removing retaining bolts or clips holding the pump assembly within the tank. The procedure is highly dependent on the tank design. Your repair manual will provide specifics.
4. Installing the New Fuel Pump:
* Install the New Pump Assembly: Carefully reverse the removal process, ensuring everything is securely seated. Pay close attention to the orientation of any seals or gaskets.
* Reconnect Fuel Lines: Securely reconnect the fuel lines, ensuring they are tightly fastened to prevent leaks.
* Reconnect Electrical Connector: Connect the electrical connector to the new fuel pump.
* Raise the Fuel Tank: Carefully raise the fuel tank back into its position. Secure the straps.
* Reconnect Fuel Lines and Electrical Connections: Double-check all connections.
5. Testing:
* Reconnect Battery Terminal: Connect the negative battery terminal.
* Check for Leaks: Carefully inspect all fuel lines and connections for leaks.
* Start the Engine: Start the engine and let it run for a few minutes. Listen for any unusual noises from the fuel pump and check for leaks again.
* Fuel Pressure Test (Recommended): Use a fuel pressure gauge (if available) to verify that the fuel pump is delivering the correct pressure. Consult your repair manual for the correct fuel pressure specifications for your engine.
Important Considerations:
* Fuel Pump Strainer: The fuel pump often comes with a new strainer (sock). Ensure it's properly installed.
* O-rings and Seals: Replace any worn or damaged O-rings or seals.
* Tank Safety: Be extremely careful when working with the fuel tank. It's heavy and could cause injury.
This is a general guide only. Refer to a repair manual specific to your 1991 Chevy S10 for detailed instructions, diagrams, torque specifications, and safety precautions. If you are uncomfortable performing this task yourself, take your vehicle to a qualified mechanic. Incorrect installation can lead to fuel leaks, engine damage, and even fire.
