Unit Injectors (EUI, MUI, HEUI) for Heavy-Duty Diesel Engines
Cairns Diesel Service supplies an extensive range of Unit Injectors for heavy vehicles, machinery and commercial fleets—including EUI (Electronic Unit Injector), MUI (Mechanical Unit Injector) and HEUI (Hydraulic Electronic Unit Injector). This technology is designed for high-power, heavy-duty and industrial diesel engines, delivering very high injection pressures without a separate common rail system.
Unit injector systems combine the high-pressure pump and injector nozzle into one compact unit fitted in the cylinder head. This design supports precise injection timing, strong power delivery and efficient combustion, helping many commercial engines meet performance and emissions requirements.

Common Symptoms of Unit Injector Problems
Failures are often caused by fuel contamination, wear, or internal leakage, and can lead to:

Rough running / misfire
Power loss and poor fuel economy
Excess smoke
Hard starting
Costly downtime for fleets and equipment.

Reconditioned Exchange & New Injectors
At Cairns Diesel Service, we supply meticulously reconditioned exchange injectors and brand-new injectors for many of the world’s leading heavy-duty engine platforms.

Supported Applications
Our inventory covers a wide range of industrial and trucking engine applications.

CAT (Caterpillar): EUI and HEUI injectors for major CAT platforms including C7, C9, C12, C15 ACERT and 3500 Series engines.
Cummins: solutions for selected heavy-duty platforms (availability varies by engine family — provide engine details or part number for confirmation).
Volvo & Scania: Bosch and Delphi EUI options for popular European heavy truck applications, including Volvo D13 and Scania D9, D12, DC13.
Detroit Diesel: EUI injectors for Series 60 applications.
John Deere & Iveco: options for selected agricultural and commercial engine applications (provide engine model / CPL / part number for matching).

Brands We Supply
We supply and support units from leading manufacturers including Bosch and Delphi, with cost-effective options available through our CDS Reman exchange program (where applicable).
Need the right injector fast? Send us your injector part number or engine model details and we’ll help match the correct injector for your application.