It is rare but the fuel injectors can fail over time either sticking or completely failing. Some racers get their injectors sent out to have them checked and balanced. There are a few shops that work on injectors and do flow testing. You want to make sure the testers use fuel instead of water. Some places use water and if you leave the injectors sitting before using they can rust or gum up internally.
Tools & Equipment
- New Fuel Injectors
- 10mm socket
- Ratchet and extension
- U-joint extension (optional)
- 9/16, 5/8 and 11/16 wrenches
- Nut Driver
- Screw Driver
- Metal Pick
- Towel or Rag
- Metal Pan
- Fuel Pressure Gauge (optional)
Replacing the Fuel Injectors
The easiest way to replace the fuel injectors is to remove the entire fuel rail. During the process of removing and re-installing the fuel rail, fuel will likely leak down as you remove pressure from fuel rail. It is a good idea to put a metal pan under the car to catch any spills.
Undo the fuel inlet and return lines using the wrenches. To make access easy it helps to remove the air inlet tube using a screwdriver and nut driver. Next undo the fuel return line followed by the fuel inlet line.
The fuel rail uses two bolts to hold it in place. Use the 10mm socket, ratchet and extensions to reach the bolt heads over the top of the intake. They can be hard to reach and a u-joint extension can be helpful.
Disconnect the electrical connectors from each of the four fuel injectors. You should now be able to pull out the fuel injectors and fuel rail.
The injectors might be difficult to remove, pulling up on each individual injector can help loosen the fuel rail.
To remove the fuel rail you have to slide it outside the intake on the drivers right side. You might also have to push some of the electrical connectors out of the way if they get caught.
Here you can see the fuel rail removed. To remove the individual injectors pull them out of the fuel rail holding onto the bodies. Watch out for o-rings that detach from the individual injectors and stay in the fuel rail. You can use a small metal pick to scoop out the trapped o-rings be careful not to scratch the sealing surface.
Insert the new fuel injectors onto the rail. Make sure to orient them so that the electrical connectors are in the right place for connecting to the wiring harness.
Slide the fuel rail back into place.
Insert the fuel injectors into their ports and press down on each to ensure they are correctly seated.
Insert the two bolts holding the fuel rail in place and ensure the threads are engaging correctly before tightening in place. You do not want to strip out the threads on the aluminum intake.
Reconnect the fuel lines using the wrenches. Cycle the cars fuel pump a few times by turing on the ignition without starting the car. Check and ensure there are no fuel leaks. If you have a fuel pressure gauge you can also check the fuel rail pressure at the sample port.
If everything looks good start the car up and check it is running smooth. If everything checks out, remove the metal pan and you are ready for your next track session.