Five Symptoms of Struggling Diesel Injectors

Tuesday, January 23, 2018

An engine is only as good as what is being pumped into it. And with that in mind, you always need to be aware of the symptoms of issues appearing in your vehicle’s diesel injectors. Here are the five most common symptoms that we think you should be aware of for your diesel car. 

Inconsistent power

If your fuel injector is dirty it can supply the engine with inconsistent levels of fuel and as a result, inconsistent levels of power. The most obvious symptom here is the engine revs changing unexpectedly and the RPM gauge fluctuating. 


This issue is usually a result of low levels of fuel being pumped into the engine on ignition. It can be caused by a variety of things, including a dirty or clogged injector or the injector failing to open. Even a small reduction in a single injector can cause a misfire on ignition, so keep an ear out.  

Uneven idling

If the engine is using differing levels of revs on idle, it’s likely due to a dirty fuel injector. A crust of leaking fuel additives can impact the rhythm of the injector and create an uneven or weak spray pattern. 

Smell of fuel

A smell of fuel means that diesel is leaking from somewhere. This could be due to a leak in one of the injectors’ seals or it could be the result of the injector valve failing to close, allowing diesel to flow out of the injector even when it isn’t active.  

Poor MPG

Surprise surprise, a leak in one of the injectors will impact the MPG that you are getting. If you’re getting a lower range than expected, even if you have lead feet, it is worth investigating any issues with the injector. Poor MPG could also be the result of an injector with a valve that doesn’t open as drops of diesel are far less efficient delivery method to an engine than misting. 

That’s our advice, keep an eye out for each of these to ensure your injectors are healthy and don’t create other issues within the drivetrain. If your injectors have reached the end of life and you’ve built up a pile of them, we want to hear from you. We can visit you and provide a quote for your parts, working or non-working. To find out more, email us on


Website design Warwickshire