Latest Industry News

What Happens When Fuel Injectors Get Dirty?

When it comes to overall vehicle functionality, fuel injectors are critical components of an engine. This is true for compression-ignition engines and spark-ignition engines alike, across gasoline-powered vehicles and diesel fuel-powered vehicles as well.

In addition to automobiles, vehicles such as boats, ATVs, and even golf carts can have fuel injectors. There is even a fuel injector in that riding lawn mower of yours.

In short, a fuel injector injects fuel into the part of the engine where the combustion needs to happen.

When a fuel injector is clean and properly functioning, this injection process is quick and efficient, with a vehicle’s engine receiving the appropriate amount of fuel at the appropriate time.

Vehicle owners with solid fuel injectors should have engines that are running smoothly because they are being powered appropriately.

But, what happens when fuel injectors get dirty?

If you’re noticing issues like rough noises while your vehicle is in the idle position, rumbles while in idle, engine misfirings, and even fuel leaks, these might be signs of a dirty or worn-out fuel injector. 

Now it’s time for some professional diagnosis and maintenance.


Image of clean Fuel Injectors


The Functionality of a Fuel Injector


A fuel injector is arguably the key component for driving the power and purpose of an engine. 

While some engine makes and models vary, there is typically one fuel injector installed per engine cylinder. For example, a four-cylinder engine will generally have four fuel injectors.

Step-by-step, when the fuel pump in your vehicle delivers fuel to your engine, these small engine components control not only the amount of fuel that goes into the combustion chamber, but they help time when that fuel is released accordingly. They are strategically placed in your engine to spray fuel into the intake manifold where it then mixes with air, is compressed within the combustion chamber section, and then you get the reaction that powers the engine for your vehicle.

Too little fuel and the reaction in the combustion chamber is not sufficient.

Too much fuel and you get things like engine flooding.

Fuel injectors are meant to last a long time with the general guidelines of replacing them every 50,000 to 100,000 miles. Now, this is all subject to overall environmental conditions, road conditions, driving stress, and overall vehicle maintenance, so regular tune-ups should include fuel injector diagnosis.


Issues Caused by Dirty Fuel Injectors


Even though fuel injectors have a long lifespan, they can still wear out.

You might even have a faulty fuel injector causing issues and if they get excessively dirty they will also not function properly.

When to replace a fuel injector is a great question any vehicle owner should ask and be aware of while regularly maintaining any fuel-powered, engine-based vehicle.

There are a few common signs that a vehicle might be dealing with a dirty fuel injector (or set of fuel injectors):

  • Rough Noises While in Idle
  • Rumbles/Shaking While in Idle
  • Engine Misfirings
  • Fuel Leaks
  • Combination of Issues

All of these reactions are due to your vehicle’s engine not receiving the correct amount of fuel at the correct time. In extreme cases, a fuel injector might be so dirty and blocked that it is not able to deliver any fuel at all.

Fuel injectors, just like any other component of your vehicle, are subject to environmental factors, road conditions, and other things that are just dirty. Debris from the road is an issue, but sometimes gunk and residue can build up from things like impure fuel, oil leaks, etc.

This is another reason why regular service and vehicle maintenance should be built in regularly for any vehicle owner.



6 Locations to Serve You


At Mac’s Radiator, our goal is to provide you with top-notch customer service with the products and skills you need to keep your vehicle running smoothly and safely. We specialize in custom radiator manufacturing and fabrication, but our extensive catalog and service options cover a wide range of products:

  • Radiators
  • Air Conditioning
  • Charge Air Coolers
  • Electric Cooling Fan Assemblies
  • Exhaust
  • Gas Tanks
  • Heaters
  • Fan Blades
  • Fan Clutches
  • Oil Coolers
  • Cooling Systems

In addition, we have a convenient online store for your perusal including a whole set of custom-made and restored items. Mac’s Radiator is also proud to offer wholesale accounts to our valued business partners.

We have six convenient locations in Portland, OR, Beaverton, OR, Bend, OR, Boise, ID, Eugene, OR, and Salem, OR, so give us a call or fill out our online form for more information.




Portland, OR      (503) 777-4706
Beaverton, OR  (503) 646-2943
Bend, OR            (541) 382-6963
Boise, ID            (208) 344-1722
Eugene, OR        (541) 344-0253
Salem, OR          (503) 364-7129



Mac's Radiator is the best mechanic to help you with all of your mechanic needs!  Let Macs help you - we are located in 6 convenient locations, for when you need us close to home, or when you're on the road.




Portland, OR      (503) 777-4706
Beaverton, OR  (503) 646-2943
Bend, OR            (541) 382-6963
Boise, ID            (208) 344-1722
Eugene, OR        (541) 344-0253
Salem, OR          (503) 364-7129

Back to top