Here's a general outline of the process. Specific steps and tools may vary slightly depending on the engine (2.2L or 2.4L) and your specific vehicle. Always consult a repair manual specific to your 1999 Pontiac Sunfire for detailed instructions and diagrams. A Haynes or Chilton manual is highly recommended.
1. Preparation:
* Safety First: Disconnect the negative battery cable.
* Gather Tools: You'll need a socket set (metric), wrenches, screwdrivers (Phillips and flathead), jack, jack stands, fuel line disconnect tools, possibly a fuel pump pliers, and a new fuel pump assembly (ensure it's the correct one for your engine).
* Drain Fuel: If possible, partially drain the fuel tank to reduce the amount of fuel you'll be working around. This significantly reduces the risk of spills.
* Locate the Fuel Pump Access Panel: This is usually located under the rear seat. You may need to remove the seat or part of the seat to access the panel.
2. Accessing the Fuel Pump:
* Remove the Rear Seat (if necessary): Consult your repair manual for specific instructions. Usually, this involves releasing clips or bolts.
* Remove the Access Panel: This will expose the fuel pump access area.
* Disconnect the Electrical Connector: Carefully disconnect the electrical connector leading to the fuel pump.
* Disconnect the Fuel Lines: This is crucial and requires caution. Use fuel line disconnect tools to prevent damage to the lines or spillage of fuel. Note which line goes where!
* Disconnect the Fuel Sender Unit (if necessary): Depending on your specific fuel pump assembly, you might need to disconnect the fuel level sender unit.
3. Removing the Fuel Pump:
* Remove the Fuel Pump Retainer Ring: This might be a retaining ring or clamp securing the pump assembly. This often requires specialized tools or careful manipulation.
* Remove the Fuel Pump Assembly: Carefully lift out the fuel pump assembly. It may be attached to a mounting plate.
4. Installing the New Fuel Pump:
* Install the New Fuel Pump Assembly: Carefully install the new fuel pump assembly, making sure it sits correctly in the tank.
* Reconnect the Fuel Sender Unit (if necessary): Reconnect the fuel level sender unit if applicable.
* Reconnect the Fuel Lines: Carefully reconnect the fuel lines, ensuring a tight and secure connection. Use clamps if necessary.
* Reconnect the Electrical Connector: Reconnect the electrical connector.
* Reinstall the Retainer Ring: Secure the fuel pump assembly with the retainer ring or clamp.
* Reinstall the Access Panel: Replace the access panel.
* Reinstall the Rear Seat (if necessary): Replace the rear seat.
5. Testing:
* Reconnect the Battery: Reconnect the negative battery cable.
* Check for Leaks: Carefully check for any fuel leaks around the fuel lines and connections.
* Start the Car: Start the car and let it run for a few minutes to ensure the fuel pump is working correctly.
Important Considerations:
* Fuel System Pressure: After installation, you might need a fuel pressure gauge to check the fuel system pressure. Consult your repair manual for the correct specification.
* Professional Help: If you're uncomfortable with any of these steps, it's best to seek professional help from a qualified mechanic. Working with fuel is dangerous, and mistakes can have serious consequences.
This is a general guide. Always refer to your vehicle's repair manual for specific instructions and safety precautions. Improperly installing the fuel pump can lead to serious damage to your vehicle or injury to yourself. Take your time, be careful, and prioritize safety.
