Diesel Injector Problems: Symptoms, Causes and Replacement

The short answer: worn or leaking diesel injectors usually show as rough idle, smoke, hard starting and poor economy. Have them tested, and in most cases replace or test them as a set.

What does a diesel injector do?

It sprays a precise amount of fuel into the combustion chamber at high pressure. Spray pattern and timing directly affect power, smoke and economy.

What are the symptoms of bad diesel injectors?

Rough idling, excess smoke, hard starting, misfires, reduced power and increased fuel use.

What causes injectors to fail?

Common causes are contaminated or poor-quality fuel, water in the fuel, clogged filters and normal wear over time.

Should I replace all injectors at once?

In most cases injectors are replaced or tested as a set, because mixing worn and new injectors can leave fuel delivery uneven between cylinders.

How do I choose the right injector?

Match the part number to your engine code. If you're unsure, send your vehicle make, model, year and engine code to Diesel Fuel Parts and ask us to help confirm the correct injector.

Who should install the injectors?

Diesel Fuel Parts supplies parts only and does not offer fitment. Injectors should be installed by a qualified diesel professional with the right tools and, on many engines, the right coding equipment, so the new parts are not compromised in any way.

Not sure which injector you need? WhatsApp us on +27 72 364 6774 with your vehicle details and we'll help you confirm the correct part.

Browse our diesel injectors.