Fuel Injector Removal and Replacement Guide

There are a few reasons that would necessitate you removing your fuel injectors. You may need to replace faulty injectors with new ones. You also might want to remove them to be sent into a mechanic who performs ultrasonic cleaning. Whatever the reason, it is a task that you can perform on your own. It does take a little skill, but doing it yourself will save you a ton of money, as any fuel system fix at a local mechanic will usually cost several hundred dollars with the labor and parts. It might seem daunting, but below we’ll walk you through the basics of finding, removing, and installing fuel injectors.

Safety First!!

This job will involve fuel (gasoline, diesel), neither of which you want to get into your eyes. Be sure to wear safety glasses or goggles to prevent splash injury. Some of the lines and hoses you will be disconnecting will be under pressure, and the glasses/goggles will keep you safe. For those of you out there that are clean freaks, pick up a few pairs of exam gloves.

Here is a list of tools you will need to get this job done:

  • Eye protection (safety glasses or goggles)
  • Nitrile exam gloves
  • Flathead screwdriver – removal of plug harness clasp
  • Ratchet set or Phillips screwdriver – removal of fuel rail
  • Fuel Injector Puller – tool used to remove the fuel injectors (not required, but makes the removal job much easier and prevents you from being too rough and potentially damaging the injector in the removal process)

Let’s dive into the important steps of removing the fuel injectors.

Plan Your Attack On Your Fuel Injector System

Most makes of vehicles build their engines slightly different from each other, so you’ll want to start out by locating your fuel injection system. Sometimes they are easy to locate and get to. Others they are in the worst spots (buried under other components). If your system is buried, you will want to learn how to access your fuel injectors by disconnecting other components first (which may take this beyond a DIY project – do some research on the web to see if you are up to the challenge).

Fuel Injector Removal

Find out if your fuel injectors are fed by a fuel rail or directly by fuel lines. If it is by rail, follow the instructions below for removal of the fuel rail. If directly by fuel lines, skip the rail step.

Depressurize Your Fuel Lines

Before you go into your engine to remove fuel lines, understand that they are always under pressure. Without depressurizing the system first, you risk damaging your system and potentially taking a gasoline shower to the face. Follow this procedure to relieve the pressure on your fuel system.

Fuel Pump Fuse

  1. Locate the fuel pump fuse or relay in the fuse box.
  2. Turn on your vehicle.
  3. Pull the fuse or relay associated with the fuel pump (this will cause your engine to sputter and die).
  4. Your fuel lines will now be de-pressurized when you open them.

Removal of the Fuel Rail

If your vehicle uses a fuel rail to deliver the fuel to the injectors, this will need to be removed next. (Fuel rail is the black bar in the image below)

Fuel Rail

  1. Remove the fuel line(s) from the rail (there might just be one, or one on either end).
  2. Unfasten the rail from the engine by undoing the bolts or screws.
  3. If there is wiring travelling over the top of the rail, you may need to disconnect the wires before addressing the rail.
  4. With the bolts or screws removed, pull up firmly on the rail until it disconnects from each injector. Most rails are simply pressed on to each injector, so give it a little elbow grease if it doesn’t want to come off right away.

Disconnecting the Fuel Line from Each Injector

If your vehicle doesn’t utilize a fuel rail, it will instead have fuel lines running to each injector. Carefully remove the fuel line from each one. (The fuel line should like something like the image below, a segment of rubber hose)

Fuel Line

Disconnecting the Wiring from Each Injector

Each injector has a plug that connects it to the electronic system of your vehicle. With the fuel delivery lines or rail removed, you should have easy access to the wiring harness plug. (The image on the left below is what the plug harness looks like. The image in the middle shows how it plugs into the fuel injector. The image on the right shows the plug in relation to the injector.)

  1. Find the plug (The plug will likely be at the top and a little off to the side).
  2. To remove the plug, you will likely have to remove a clasp or wire tension piece.
    Carefully wedge a flathead screwdriver in between the clasp and the plug housing and pry it off (be careful not to lose it).
  3. The plug should easily come off.

Removing Each Fuel Injector

Now that the wiring is disconnected, the fuel injectors can be pulled out. Care is needed in the step the most as any piece that is broken off the injector will fall into the sensitive parts of the engine and cause a massive headache if not addressed. Don’t stress too much, but be careful. If you have access to a fuel injector pulling tool, this is where you will use it. If not, you will need to carefully pull it out. The tool inserts under the lip of the injector housing, and then you just pop it up. (Pictured below)

Fuel Injector Puller

Remember that removing the injectors leaves a hole into your engine. While you are working on cleaning or replacing your injectors, don’t let anything fall into those holes! This can’t be stated enough. DON’T LET ANYTHING FALL INTO THE HOLES!! Good.

Replacing Fuel Injectors

Now that your old injectors are out of the way, it is time to install new ones (or the same injectors that you had professionally cleaned and tested). If replacing with new injectors, be sure to source fuel injectors compatible with your vehicle.

Replacing the fuel injectors basically goes in a reverse order of the removal, here is a quick breakdown:

  1. Lube the seals and o-rings of the injectors you are installing.
  2. Insert the injectors into the holes (plug and fuel line side up). Use a mild pressure to carefully insert them until they are seated properly. Don’t force them in.
  3. Replace the wiring harness into plug and re-attach the clasp.
  4. Replace the fuel lines directly to the injectors, or replace the fuel rail (gentle pressure to snap it on to each injector) by securing it with the screws or bolts. Replace the fuel rail fuel lines.
  5. Replace any wiring that was disconnected.
  6. Replace anything else that was in the way before you started on the fuel injector system.
  7. You should now be good to replace the fuse or relay for the fuel pump and fire your vehicle up. Take it for a spin and see if you can feel the difference that brand new fuel injectors can bring!

Summary

Replacing your fuel injectors isn’t a difficult job, but will require a little finesse around the engine. It doesn’t hurt to know a little about how an engine works, but anyone can really accomplish the task (as long as the injectors aren’t buried for some reason). Hopefully this guide will help you to tackle this DIY project. If not, watch a video or two to get you going. Thanks for stopping by and good luck!

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