Noticing some strange things happening with your heavy machinery – starting issues, poor performance, increased fuel consumption, smoke…?

These could be symptoms of dirty fuel injectors and it’s important to be able to diagnose and fix dirty fuel injectors promptly.

Here we explore the main symptoms of dirty fuel injectors and the causes and fixes.

Symptoms of dirty fuel injectors

Firstly, you’ll need to know the main symptoms of dirty fuel injectors so you can keep an eye out and be able to diagnose issues early on.

Top signs of dirty fuel injectors include:

• Misfiring engine – if an inadequate amount of fuel isn’t getting into the engine, the engine will misfire (note: engine misfire can also be a sign of a faulty spark plug, ignition coil or worn cylinder).
• Machine stalling – engine stalling can occur when dirty fuel injectors are badly blocked, as an uneven supply of fuel during idling can cause a large drop in RPM.
• Poor idle – you might feel your machine vibrating while sat at idle and might hear the engine cutting in and out.
• Check engine light – if this comes on, it might mean that too much or not enough fuel is getting to your engine because of dirty fuel injectors.
• Failed emissions – clogged or dirty fuel injectors
• Poor performance
• Increased fuel consumption
• Smoke
• Engine knock

What causes dirty fuel injectors?

Dirty fuel injectors can be caused by hydrocarbons, sediments and other elements and impurities found within your diesel. Rust, for example, is a material that can commonly clog your fuel injectors and this can appear within your system if water is present in your diesel (learn more about diesel contamination in our full guide.)

How to clean dirty fuel injectors

View our full guide to cleaning dirty fuel injectors (summarised below).

1. Remove the fuel tank cap
2. Remove the fuel pump fuse to disconnect the fuel pump
3. Connect the fuelling system’s output hose to the cleaning kit (check kit for specific instructions)
4. Start the engine and let it run. This should take approximately 15 minutes.

How often should you clean fuel injectors?

We’d recommend cleaning fuel injectors at least once a year, but also if there’s been a significant decrease in performance noticed in your machine or if there is black smoke coming from the exhaust.

Cleaning or replacing dirty fuel injectors?

How can you know when it’s time to replace your fuel injectors, as opposed to simply cleaning them? If, after cleaning your dirty fuel injectors they’re still not performing as well as they should be, it could be time for a replacement. There are 4 main signs that this could be the case:

• Loss of power when stepping on the throttle
• Poor fuel efficiency and higher consumption per hour
• Engine misfire and stalling or hesitating
• Excessive exhaust smoke and fuel smell

Fuel injector parts are crucial for delivering the right amount of fuel to your engine, and to ensure optimal engine performance. At Jaytrac, we stock a range of fuel injection parts, including Cummins PT and Celect units, HEUI units, Perkins CAV units and more.

Since our founding in 1995, we have been dedicated to supplying quality replacement parts for heavy machinery, with product quality and customer service at the heart of what we do. To get in touch, call us on +44 (0) 1604 491133 or email sales@jaytrac.co.uk. Alternatively fill out a contact form with details of your enquiry and we’ll get back to you as soon as possible.