How to Rebuild an Injector

  • 2-4 hours
  • Advanced
What You'll Need
Socket wrench kit
Wrench kit
Carburetor cleaner
Air compressor and hoses
Wire and 12 volt battery
Fuel injector pump rebuild kit
Safety glasses

Injectors are among the most critical components of a vehicle's engine. The fuel injector controls the flow of gasoline or diesel into the combustion chamber. Over time, impurities in the fuel will cause sludge and deposits to build up in the injector. This reduces engine performance and can eventually cause the injector to plug up. The three main causes of fuel injector failure are a burnt-out solenoid, corroded electrical contacts, or leaky seals. If you have the proper equipment and plenty of patience, it is possible to clean and rebuild your own fuel injector. This will save you money over having the part repaired professionally. However, you must be careful. The internal components of the fuel injector are very delicate and can be damaged easily by rough handling or the wrong cleaning chemicals. The tolerances on the injector are very low and it easy to mess it up. If you are not confident in your abilities you can opt to remove the injector yourself and send it away for rebuilding. This is cheaper and more convenient than visiting a garage.

Step 1 - Obtain Rebuild Kit

The first step in the repair process is to obtain an injector rebuild kit. This usually includes a filter, spacer, pintle cap, and o-rings. These parts will be fitted to your vehicle's make, model, and year. Find a large quantity of carburetor cleaner and bucket as well. Remove the injector pump from the fuel line. Bring it to a clean, well-ventilated, and well-lit work area.

Step 2 - Take Injector Apart

Remove the O-rings at either end of the injector and soak it in carburetor cleaner overnight. The next day, remove the injector from the bucket and blow it clean with compressed air. Rinse the remaining cleaning solution from the injector.

Step 3 - Clean Injector While Applying Power

The injector is controlled by a solenoid which opens a valve. Opening this valve while you are blowing air through the injector is critical to a thorough cleaning. Find an old injector wiring connector from a junk yard and use it to wire the injector a battery and to the ground. Apply power briefly to open the valve and clear the injector. However, do not apply power to the injector continuously or you will overload it. Continue to clean the injector with an ultrasonic cleaner if you have one available.

Step 4 - Rebuild Injector

Cut off the pintle cap and remove the spacer. Be extremely careful from this point forward. Touching the pintle at any time can ruin the fuel injector. Remove the fuel filter by poking it out with a sheet metal screw. Tap the new filter into place with a mallet. Heat the new pintle cap to help it slide on. Finally, replace the o-rings and reinstall the fuel injector.