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How to Tell If a Fuel Injector Is Clogged, Dirty, Faulty, or Leaky

Educational  ·  May 19, 2020

How to Tell If a Fuel Injector Is Clogged, Dirty, Faulty, or Leaky

Modern cars are true marvels of engineering. Under the hood of each one lays hundreds of car parts in all shapes and sizes, all working together to provide you with comfort and performance. From time to time, some of those parts may lose their ability to perform well. This is normal for a car as part of its regular wear and tear.

While this is something that every car owner should expect, sometimes, it's not always obvious when something like your car's fuel injector stops working correctly. Sure, you could wait for the 'Check Engine' light on your instrument panel to come on. But that warning light won't be able to tell you the whole story.

In this day and age, you can opt to invest in something like a vehicle health monitoring system, which is designed to diagnose car issues like a fuel injector that isn't working right. Expect it to cost you a bit of money, though.

Alternatively, you could do it the old-fashioned way. People who are very familiar with their cars can tell when something's wrong. They do this by noticing the little signs that hint at a problem. In this article, we'll go over a few basic signs that your fuel injector might be clogged, dirty, faulty, or leaky.

What a Fuel Injector Does

First and foremost, let's get on the same page about what a fuel injector does for your car. Fuel injectors are a crucial part of any combustion engine. When the injector receives a signal from the Engine Control Unit (or ECU), the fuel injector will spray fuel into the engine. This fuel is pressurised so that it can then be combusted to produce power to move the vehicle forward. In the past, cars used carburettors for the same purpose. Somewhere in the 1980s though, fuel injectors replaced carburettors.

Signs Your Fuel Injector is Clogged, Dirty, Faulty, or Leaky

So let's take a quick look at a few common signs that your fuel injector might not be working right.

Your 'Check Engine' Light Comes On

There are many signs that you have a problem with your fuel injector. The first one, as mentioned earlier, is when your 'Check Engine' light turns on in the instrument panel on your dashboard. Again, this light coming on could mean many different things, but a problematic fuel injector is undoubtedly one of them.

Confused about what all those warning lights mean? Not to worry. The 'Check Engine' light is the one that is shaped like a car engine.

Your Car Idles Roughly

Sometimes, all you have to do to see if you have a problem is to let your car idle. Start your vehicle and let it sit there for a while, as you pay attention for sounds and shaking that's unusual. Instead of your car idling peacefully, it might start to shake randomly, as if the engine is choking from time to time. You might even notice the engine's RPM fall below its average level, causing the engine to stall completely.

These symptoms happen because a faulty fuel injector will not supply your engine with fuel in a consistent way. When this happens, your car won't be able to idle peacefully, indicating that there's a problem you need to get sorted out.

You See/Smell Fuel Where It Shouldn't Be

Sometimes, a fuel injector might become cracked or broken with age. There may even be a problem with the fuel injector seal that could also cause a leak to happen. As a result, fuel will leak out from the injector and reach places it shouldn't be. Check under the hood and look around the fuel injector to see if there's gas on its exterior.

Also, pay attention to any smell of fuel. When a fuel injector isn't working properly, you might be able to smell the fuel that isn't burned correctly inside the engine.

Here's a bonus tip: to find out if your car is leaking something, anything at all, pay attention to the floor where you park your vehicle overnight. Some people might even tell you to lay out some paper or a wide-enough container to catch whatever might drip down. The following morning, you can see for yourself if there's fuel or oils that'll indicate you have a leak.

Your Engine Vibrates or Misfires When Driving

When your fuel injector stops working correctly, you’ll most likely notice it while you're driving. Since the engine isn't receiving a constant, stable supply of fuel from the injector, you'll feel the engine vibrating randomly and even misfiring. On a technical level, the vibration and misfiring happen when some cylinders inside the engine aren't able to fire as they should.

What Can Be Done About a Faulty Fuel Injector?

If your fuel injector isn't working right, you'll need to take it to a workshop or your mechanic to get checked out. They'll need to diagnose the problem up close to decide what needs to be done next.

In most cases, a faulty fuel injector that's clogged or dirty can be sorted out with a good cleaning. You could buy a fuel injector cleaner, or even a DIY cleaning kit to sort out problems that may be causing minor issues. For more severe issues, you may need to hire a professional to deep clean it for you. Sadly, if your fuel injector is cracked or broken, you'll need to replace it entirely.

No matter what option you go with, you may end up spending quite a bit of money. While it can be expensive, you should remember that fuel injectors are some of the essential parts needed for your car to operate. So, you definitely don't want to skimp on them. Instead, you'd be better off in the long run if you invested money in keeping your fuel injectors well-maintained. 

This is also true if you were buying replacements – you should try to invest in solid, high-quality parts. Rely on your trusted car part suppliers, or if you’re looking for new auto parts sources, we’re inviting you to try our Request a Part feature. It’s the safest and most convenient way to buy a part in Australia. Access this online parts request tool free here!

By Ray Hasbollah

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