Here's a general outline. Specific details may vary slightly depending on your exact model and engine:
1. Safety First:
* Disconnect the battery's negative terminal. This is crucial to prevent accidental sparks.
* Allow the fuel system to depressurize. Let the engine run until it stalls (if possible) or wait several minutes after turning off the ignition to allow pressure to bleed off. You may need a fuel pressure gauge to confirm low pressure for safety.
* Work in a well-ventilated area. Gasoline fumes are highly flammable and potentially harmful.
* Wear safety glasses and gloves.
2. Access the Fuel Pump:
* Locate the fuel pump access panel. This is usually located in the trunk, often under the carpet or a panel. Consult your owner's manual for the exact location.
* Remove the access panel. This typically involves removing screws or bolts.
3. Remove the Fuel Pump:
* Disconnect the electrical connector. This is the wiring harness connected to the fuel pump.
* Disconnect the fuel lines. These will be fuel-in and fuel-out lines. You'll likely need fuel line disconnect tools to prevent leaks and damage to the lines.
* Remove the retaining ring or bolts. This secures the fuel pump assembly to the tank. The method varies; some use a retaining ring that needs to be carefully pried up, while others use bolts.
* Lift out the fuel pump assembly. This assembly usually contains the fuel pump, fuel level sensor, and other components.
4. Replace the Fuel Pump (if necessary):
* Install the new fuel pump assembly. Ensure that it's seated correctly.
* Reinstall the retaining ring or bolts.
* Reconnect the fuel lines. Securely attach them using the appropriate tools.
* Reconnect the electrical connector.
* Reinstall the access panel.
5. Post-Installation:
* Reconnect the battery's negative terminal.
* Start the engine and check for leaks. Look carefully around the fuel lines and the access panel.
* Check the fuel gauge for proper operation.
Important Notes:
* Consult a repair manual specific to your 1999 Cadillac DeVille. This is essential for accurate instructions and diagrams. Repair manuals provide detailed steps and illustrations, significantly reducing the risk of errors and damage.
* If you're not comfortable performing this repair yourself, take your vehicle to a qualified mechanic. Working on fuel systems requires experience and specialized tools. Improper repair can be dangerous and costly.
This information provides a general overview. Always refer to a specific repair manual for your vehicle's year and model for detailed and accurate instructions. Safety should be your top priority when working on your vehicle's fuel system.
