Has anyone ever changed their fuel injectors?


Well-Known Member
I ordered new fuel injectors and they are on their way but it is the first thing I have ever searched for on google/you tube on how to do something that their was not one how to video which has me a bit worried.
So I was hoping someone on here has done it and let me know if their is anything that I should prepare for or any special tools I might need.
Thank guys any info will be a great help and well appreciated


Lifetime VIP Supporter
Start by Downloading a GM OEM Service Shop Manual for your specific Vehicle (Courtesy @Mooseman) via THIS Link as it will be always be “The Official GM Bible” for all Repairs:


...and this Link will help you to deal with the most difficult problem you’ll face of getting The Intake Manifold Off:

From “It Still Runs...”:

Step 1

Relieve the pressure in the fuel system by removing the fuel pump relay, located in the relay box near the driver’s-side fender well. The cover of the relay box shows you which injector is the fuel pump injector. Remove the relay, then crank the TrailBlazer over a couple times.

Step 2

Clean the fuel rail with carburetor cleaner and rags. Remove the battery ground cable and set it aside, ensuring that it does not touch metal.

Step 3

Remove the intake manifold by unbolting it and lifting it off the engine. Lay rags in the space left by the intake manifold, so that debris does not fall into the engine. Using the appropriate wrench, remove the fuel feed and return pipes.
Step 4

Loosen the clamp on the fuel pressure regulator vacuum line, the pull the line off the regulator. Remove the fuel feed and return pipes using the appropriate wrench. Unplug each fuel injector’s electrical connector by pushing in on the plastic tabs and lifting the plug out of the injector. Unbolt the fuel rail retaining bolts and lift the rail off the engine.
Step 5

Pry the injector’s retaining clip off with your fingers or a screwdriver. Only remove those clips for the fuel injectors you are replacing. Pull the injector off the fuel rail.
Step 6

Oil the new injector O-ring seats with engine oil. Slide the new O-ring on the injector (each injector comes with a new O-ring and retainer clip). Snap the new retainer clip onto the injector.
Step 7

Push the injector into its socket on the fuel rail with the connector facing outward. Make sure the retainer clip locks on the flange on the fuel rail injector socket. Gently place the fuel rail on the engine, lining up the fuel injectors. If one of the injectors touches the engine, lift the rail off and make sure that no debris got onto the end of the injector. If it did, clean off the bottom of the injector with carburetor cleaner.

Tighten the fuel rail retaining bolts to 89 inch-pounds of torque. Reattach the fuel feed and return lines on the rail. Plug in the fuel injectors electrical connectors. Replace the vacuum line on the fuel pressure regulator. Reinstall the intake manifold and the battery cable. Plug the fuel pump relay in. Turn the engine on for two seconds, then off for 10 seconds to prime the fuel system. Start the TrailBlazer and check for leaks.
Items you will need

  • Rags
  • Carburetor cleaner
  • Set of wrenches
  • Set of sockets
  • Torque wrench (inch-pounds)


I've done it, hardest part is removing the intake manifold. Rest is pretty easy with the rail right there exposed.


Silver Supporter
While you're replacing the injectors. I would replace the gaskets for the intake manifold and the valve cover. You're not going to want to take that intake manifold off again.


Well-Known Member
You may also want to replace your thermostat and coolant temp sensor while you're there....also the purge valve solenoid which is on the block under the fuel rail.

When removing the injectors from the rail, note how the retaining clip is seated. Take your time removing and re-installing the metal retainers..if you booger one up obviously you will need to source another.


Well-Known Member
All the new injectors are in!! The intake manifold was a bitch but not as bad as I thought it would be. Only issue now is my throttle body is bad, it was fine before the tear down but won’t work at all now so maybe it was just it’s time?
Thanks everyone for all the help I really used all of the input

Online statistics

Members online
Guests online
Total visitors

Members online

No members online now.

Forum statistics

Unanswered questions
Answered questions
Latest member
Top Bottom