The move from carburetors to fuel injectors has made car and truck engines much more reliable. While some people might still enjoy tinkering with old carburetors on their classic cars, fuel injection represents a solid innovation in the industry. They make your engine much less likely to experience problems with the fuel system.

Fuel injectors aren’t infallible, though. It’s true they have fewer issues than carburetors, but fuel injectors can still have problems. Knowing what causes fuel injectors to go bad can help you diagnose the issue and prevent it from happening in the first place.

What Causes Fuel Injectors to Go Bad?

If you’re having trouble with your fuel injectors, odds are pretty good that one of these three causes is to blame.


Let’s dispense with the suspense and get right to the main culprit when it comes to why fuel injectors go bad: poor fuel quality is the most common reason for fuel injector problems.

When you think about how a fuel injector works, this makes perfect sense. A fuel injector does exactly what its name suggests. When it injects the fuel into the combustion chamber, it partially atomizes it, kind of like the nozzle on a paint sprayer. The components need to be clean and clear in order to function properly. Like a lot of fine-tuned systems, a little obstacle can really throw off the entire system.

Impurities Are the Enemy

Poor quality fuel gets in the way of the injection process because it contains impurities that build up in the fuel system over time. These impurities can clog the fuel injectors, leading them to perform poorly or even fail. Anything from dirt particles to rust and even water in the fuel can block your system.

Fight Back With High-Quality Fuel

Fortunately, there are things you can do to prevent getting poor quality fuel in your system. The first thing is to think about where to get your fuel. Opt for places known for high fuel quality and go there consistently. You might have to pay a little more, but it will be worth it in the long run to keep your system cleaner. The costs of a clogged system will ultimately outweigh the cost of a few extra cents per gallon.

Another variable is timing. Avoid getting fuel right after the gas station gets a new shipment, if you can. Waiting for any impurities in the fuel to settle in the gas station’s tanks will make it less likely that they will wind up in your system.

Break Down Impurities

Fuel additives are another way to keep your system running clean. They help break down impurities and prevent them from building up and clogging your system. You probably don’t need to use an additive every time you gas up, but doing so regularly will help keep your system clean so you can keep your fuel injectors clear. Do some research or ask your mechanic what product would be best for your system.


Sometimes, it’s not the fuel or even the injector, but the injection system causing the problem. Components of the fuel injection system themselves can experience structural damage. The internal seals in the fuel injection system can wear down over time and start to leak. The return spring can also wear out, or the pintle can get damaged.

Structural damage to the fuel injection system can result from normal wear and tear or from poor installation when the injectors are put in.


Of course, the problem can also lie in the injectors themselves. Fuel injectors can fail and cause problems from there. For example, the injector solenoid can fail, which will result in the injectors getting power for longer than they should. This will cause the injectors to eventually burn out and fail.

Indications of Bad Injectors

Knowing why fuel injectors go bad can help you identify the cause. Identifying the signs of a bad injector can help you pinpoint when to look at your system. The following symptoms are common in bad fuel injectors.


Engine misfires result from having too little fuel in the combustion chamber. This typically results in poorer engine performance.


A rough-running engine is a common symptom of a bad injector. Rough idling with more vibration than normal is a sign that something could be wrong with the injection system.


Inconsistent performance, like a variation in RPMs, is a strong sign that the injectors need to be looked at.


Smelling fuel around your engine is an indication that the fuel injectors are having trouble. If a seal is loose or there is something else wrong structurally, small amounts of fuel can leak from the system.

How to Keep Fuel Injectors from Going Bad

There are a few things you can do to keep your fuel injectors working as they should. As mentioned earlier, be mindful of where you buy your fuel, and use a fuel cleaning system on a regular basis. This will help keep fuel injectors from getting clogged by impurities in the fuel. A little regular maintenance is key to keeping an engine healthy.

You can also clean your injectors on a regular basis. Once you learn how, this is a process you can do yourself, if you choose. You can also have your mechanic do it for you. This is a good opportunity to check for signs of wear and tear or possible failure among the injectors.

Start with Dieselogic

One of the best ways to prevent bad fuel injectors is to buy high-quality injectors from the start. There are a lot of injectors to choose from and places to buy them. With Dieselogic parts, you know you are getting quality parts for your engine.

Your fuel injectors are a fine-tuned system that helps your engine run more efficiently, get the power it needs, and reduce emissions. Bad fuel injectors get in the way of all that. If you keep these tips in mind, you can keep your engine running as it should.