When to Replace Fuel Injectors: Their Milestones & Signs of Bad Ones!

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When to Replace Fuel Injectors

When to replace fuel injectors is a common concern for any car owner. With fuel injectors, there are telltale signs that it’s time to “upgrade” them. Like any other mechanical or computerized machine, fuel injectors will eventually start to wear out. If you have reached a certain mileage or you see any sign of wear and tear, it’s time to get it replaced.

In short, you should change fuel injectors when it’s served you 50k-100k miles or you see that your vehicle has some symptoms including misfiring, consuming more fuel than normal, gas odor, check engine light turning on, or fuel leaking. Let’s look into the details.

When to Replace Fuel Injectors

#1 How Long Does a Fuel Injector Last

Typically, an injector lifetime can be up to 100k miles but it depends on many other factors as well. Sometimes, the car owner is unaware of how many were used. That’s why it’s important to consider all the possible factors before you go for a change. Here are some common ones:

Fuel Quality

Aside from the running miles, the type of fuel your vehicle uses may also affect its life span. Most fuel injectors can last up to 50k on average but some may not reach 30k miles. If your vehicle uses ethyl gasoline, it can go longer than if it runs with high octane gas. This is because running with high octane gas will clean the emissions quicker, removing the carbon deposits on the inside of the injector. This leads to less wear and tear on the injectors.

Driving Conditions

City driving might affect fuel mileage while racing may shorten its life span. In addition, some fuel injectors may be used in different models of the same car. Be sure to check your car on a regular basis and clean it from time to time, this will help extend its lifetime.

Air Filters

Your fuel system might have been affected by an air filter that needs replacing. It can block the air supply needed for proper fueling. This can cause the injector to fail prematurely.

Poor Maintenance

Most of the time, the fuel injectors are hard to spot. This makes you think that it’s okay even if you didn’t clean them for a long time. Some owners only inspect the fuel injectors when they detect a problem. Lack of maintenance also reduces their lifetime.

Usage of Aftermarket Parts

They might affect your car’s performance and that’s why some car owners decide to replace them with OEM parts instead of aftermarket ones. Aftermarket parts are cheaper but may cut the fuel injector’s life span.

#2 Signs of Bad Fuel Injectors

If you think that you are due for replacement, check out some telltale signs that your injectors are about to fail soon. They are:

Check Engine Light Turning On

As early as 15k miles before they fail, some cars develop “misfire” which causes their check engine lights to turn on. The levels of misfiring are beyond the manufacturer’s recommendations.

Remember that there are many reasons causing the Check Engine Light to turn on, bad or clogged fuel injectors can be one of them.

Fuel Odor

If you smell something rotten in your car, it might be time to change it. You can test this by switching out your fuel and driving around for a while. If it doesn’t smell, chances are they won’t fail soon.


You can check your car for this by observing the idle. If you notice that the vehicle keeps running rough or having trouble accelerating, it’s a big indicator that you have a misfiring problem. Misfiring means that those fuel injectors are not working as they should. It occurs when your car is unable to get a proper supply of air and gas mix in the combustion chamber.

Your check engine light will turn on and you’ll need to replace them right away.

Fuel Leaking

If the fuel injectors are damaged or cracked, they may start leaking fuel. Check for fuel trail of smoke coming from the damaged area. If it’s leaking, you need to replace it right away.

The milky color of the injector is another sign that it has already cracked.

Declining Fuel Efficiency

If your vehicle’s fuel efficiency is declining, it’s a good indicator to think about replacement. Check and if the intake and exhaust temperatures are sticking out too high, chances are that there is a problem with the fuel injectors.
Fail injectors send wrong data to the ECU to demand more fuel than the car needs. This can also increase the emission level.

How to Change Your Fuel Injectors?

Fuel injector replacement needs special equipment and tools. You can shop for them at your local auto parts stores or order them online. If you’re skillful enough, then you can do it yourself. However, I highly recommend you get help from a professional.

When you take your car to a mechanic shop, expect to pay up to $1500 (this number varies on your make and model). The parts themselves are quite expensive, not to mention the labor cost. If you want to save some money you can go for aftermarket parts. So make sure you look around for your budget.

How to Clean Fuel Injectors?

Cleaning them regularly (after every 30k miles) can help to prolong their life and prevent them from getting clogged. This cleaning job isn’t that challenging and costly. If you opt for a DIY task, you just need a fuel injector cleaning kit, check out this article for more details:

> How to Clean Fuel Injectors Without Removing Them

Otherwise, you can get a professional service. You can set aside around $100 for this service.

Final Words

Fuel injectors won’t last forever. They need to be replaced in due time. Whether you do it yourself or let someone else do it, the most important thing is to keep them checked on a regular basis.

Observe your car’s performance and if it doesn’t feel right, then the best thing that you can do is replace it. You don’t have to wait until they fail. Just follow these tips and you can extend their life span by quite a lot.

Changing fuel injectors is a major job that requires a lot of skill, patience, and experience. If you don’t have the right tools and experience, you might end up doing more harm than good. Take your car to an automotive shop if needed.