Here's a general outline of the process. This is NOT a complete, step-by-step guide, and specific procedures may vary slightly depending on the engine (4.2L or 4.3L V6, or 5.3L V8). Consult a repair manual specific to your Blazer's engine for detailed instructions and torque specifications.
1. Safety First:
* Disconnect the negative battery terminal. This is crucial to prevent electrical shorts and shocks.
* Work in a well-ventilated area. Fuel vapors are flammable and potentially harmful.
* Wear safety glasses and gloves.
2. Preparation:
* Gather your tools: You'll need a socket set (metric), wrenches, fuel line disconnect tools, fuel injector removal tool, rags, shop towels, a fuel pressure gauge (to relieve pressure), and possibly a fuel injector o-ring kit.
* Consult a repair manual: This is absolutely essential to identify the correct fuel injector location and understand the specific steps for your engine. Diagrams are invaluable.
* Locate the fuel injectors: They are usually located on the intake manifold.
* Relieve fuel pressure: This is critical. The repair manual will show you how to do this safely, typically involving disconnecting a fuel pump relay or using a fuel pressure release valve. Never attempt this step without consulting your manual.
3. Injector Removal:
* Disconnect the electrical connectors: Carefully unplug the electrical connectors from each fuel injector.
* Disconnect the fuel lines: Use fuel line disconnect tools to carefully separate the fuel lines from the injectors. Be prepared for some fuel spillage – have rags ready.
* Remove the fuel injectors: Use a fuel injector removal tool to carefully remove the injectors from the fuel rail. These tools usually grasp the injector body and help pull them out evenly. Be very careful not to damage the injectors or the fuel rail.
* Inspect the o-rings: Check the o-rings on the removed injectors for damage. Replace them if necessary.
4. Injector Installation:
* Install new o-rings (if needed): Carefully install new o-rings onto the new injectors.
* Install the new fuel injectors: Carefully insert the new fuel injectors into the fuel rail, ensuring they are seated properly.
* Reconnect the fuel lines: Securely reconnect the fuel lines to the injectors.
* Reconnect the electrical connectors: Carefully plug the electrical connectors back onto the injectors.
5. Final Steps:
* Reconnect the battery: Carefully connect the negative battery terminal.
* Check for leaks: Carefully inspect all connections for leaks.
* Start the engine: Once you've confirmed there are no leaks, start the engine and check for any unusual noises or running issues.
* Check for diagnostic trouble codes (DTCs): Use an OBD-II scanner to check for any error codes that may have been triggered.
Important Considerations:
* Fuel injector flow testing: Before installation, consider having your new injectors flow-tested to ensure they are within specifications. Many auto parts stores offer this service.
* Fuel rail pressure: The fuel rail needs to be properly pressurized for the engine to run correctly. If you have problems after installation, have your fuel rail pressure tested.
* Professional help: If you encounter any difficulty or are unsure about any step, seek professional help from a qualified mechanic. Improper fuel injector installation can cause significant engine damage.
This is a simplified overview. Always consult a repair manual specific to your 2003 Chevy Blazer's engine before attempting this repair. The manual will provide detailed diagrams, torque specifications, and step-by-step instructions to ensure you perform the job safely and correctly. Improper installation can result in costly engine damage.
