How to Guides

When To Change Fuel Injectors

Zaki Moulvi posted this on Jun 9, 2014

When To Change Fuel Injectors

Fuel injectors work by precisely supplying the engine with the exact amount of gas it needs, at the best possible moment so that it can ignite and keep your motor running.  Some manufacturers like to suggest that their fuel injectors are built to last the life of your car, but with so many variables, like the cleanliness of the gas you fill your tank with, it is impossible to say that with certainty. 

How to Prolong the Fuel Injectors Life Span

There are certain steps you can take to help keep your fuel injectors healthy:

  • Use high quality gas from a reputable fill station.  Water and dirt in the gas will not only harm your fuel injectors, they can be detrimental to your entire fuel system.  Some gasoline blends will even help keep your fuel injectors from getting clogged by adding special detergents that break down deposits.
  • Be aware of your driving habits.  Stop and go traffic harms your fuel injectors as an idling engine allows the debris found in fuel to settle inside of them.  Avoid short trips and frequent stops to help keep the injectors clean.
  • Changing your fuel filter regularly will also help keep the fuel injectors healthy.  The number one problem with injectors is build-up of debris in the nozzles, so if you can keep the gasoline clean, you should be able to keep the injectors working right.
  • Add a fuel injector cleaner to your gas tank.  This additive will circulate with the gasoline and help break down any deposits in the fuel injectors.

How Can I Tell That My Fuel Injectors are Bad?

Misfiring is the main symptom of clogged fuel injectors.  This is when the engine is not getting any type of power from one or more of its combustion chambers.  Your vehicle will be sluggish and possibly idle roughly. 

Dirty fuel injectors are sometimes stuck in an open or closed position.  One that does not open will make it difficult for you to start your car and you will experience a general lack of power from your engine.  An injector that will not close due to a build-up of debris will cause your car to lose fuel pressure and allow gasoline to enter the motor oil sump.  You can verify this by smelling the oil on the oil level dipstick.  If you can detect a gas smell than you know that one of your injectors is leaking fuel.

Flushing the Fuel Injectors

Before making the big decision to replace the fuel injectors, you can try flushing them first.  Although this is a job that can be done at home, you do need to proceed with caution.  Cleaning the fuel injectors involves opening the fuel line, so make sure that you are in a well ventilated area free of anything that could cause a sudden spark.

  • Purchase a fuel injector cleaning kit through  Their friendly staff can help direct you to the one that will work best for your type of vehicle.
  • The fuel pump will have to be disconnected from the injectors and a U tube inserted to ensure that the gas is returned to the tank as you are cleaning them.  You will also need to disconnect the pressure regulator.  Follow the directions laid out in your owner’s manual.
  • Follow the directions on the fuel injector cleaning kit to attach it to fuel port. 
  • Open the cap for your fuel tank to help relieve the pressure that will be generated when you start the cleaning process.
  • Double check that the fuel pump is disconnected and start your car.  The process should take anywhere from 5 to 10 minutes for all of the cleaning fluid to cycle through the fuel injectors.  Once complete, your car will shut off automatically.
  • Disconnect the cleaning kit, reconnect the fuel pump and close the gas tank cap.  Take your car for a  test drive to make sure that everything is running smoothly.

When is Cleaning Fuel Injectors Not Enough?

An overheated engine or over use can cause cracks to form on the body of the fuel injector.  If cleaning them did not help improve your engines performance, then you may have to consider this as a possibility.  At this point you will have no alternative but to replace the fuel injectors.

Before getting started, you will need to purchase a new set of injectors for your car.  It makes no sense to go through all of this trouble to only replace one or two fuel injectors.  To ensure that the fuel injectors you purchase will meet your vehicles OEM standards, buy them through

Like cleaning the injectors, replacing them is hazardous due to the exposure to gasoline.  Before you decide if you want to take on the project yourself, be sure that you have a well ventilated area to do it in.  Again you will have to disconnect the fuel pump and run a U hose back to the gas tank, but replacing the fuel injectors also involves disassembling the fuel rail.  Once you have that removed you can access the fuel injectors.

  • Remove the plug from the top of each fuel injector using a flat head screwdriver to pry it away.
  • Use a fuel injector puller to pull the injectors out.  You have to be very careful not to break off any pieces or allow any debris or small parts to fall inside of the hole.  If something gets inside of the intake manifold or head it is a real pain to get it out.
  • Once you have all of the injectors removed, simply replace them with the new ones using lubricant and reattach the plugs.
  • Replace the fuel fail and reconnect the fuel lines and now your engine should be running just like new.

Fuel injectors play a massive role in the way your car runs.  It is responsible for the power, efficiency and even the amount of emissions released by your engine.