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Portlaoise Diesel Injection Ltd is owned by John Brennan, who has over 30 years' experience in the diesel industry.​ We are located on the Timahoe Road in Portlaoise. Co. Laois


We are one of the top Diesel Repairs companies in Ireland. We can test & repair most of the leading diesel injectors and pumps inc Bosch, Siemens, Delphi, Denso. We also stock a large quantity of new parts for any type of Diesel Vehicle or Engines.


We have a dedicated workshop with three fully qualified Diesel Technicians this includes technologically advanced state-of-the-art common rail systems and electronic diesel control (EDC) systems for both cars and commercial vehicles

Our injectors are coded where necessary with IMA coding, this is an industry standard which is required allow the ECU to vary fuel accordingly and optimise engine performance.

Opening Hours:


MONDAY - FRIDAY: 9:00 AM - 5:30 PM



057 8621024
086 8945350​

Timahoe Road



R32 K820

About Us

Established in early 2000, our diesel repair centre has grown from a tiny one-man show into a thriving national operation 

In the late '70s, John Brennan discovered his passion and talent for innovative diesel performance injection systems and repairing diesel pumps, while under the watchful eye of Tom Cooney


After honing his diesel repair skills, John set up his small repair shop at his house.  Portlaoise Diesel Injection was open for business, though business wasn't exactly booming John sweated out the rough in the early years the only way he saw fit—by establishing innovative diesel performance that saves customers money over the long haul and by providing dedicated, honest service.


Remaining true to those core values to this day. Portlaoise Diesel Injection has earned its place as a leader in the Irish diesel market and later looked to expand on that success. 

The company expanded its workforce to fifteen over the years and in 2012 they moved to a larger premises where business continued to grow. John now had a garage running full time alongside his repair workshop. 

In January 2022 John leased the garage aspect of the business to Laois Auto Care to let John focus on his real passion of repairing the pumps and injectors

Our Services


​- Injector Test & Repair

- Pump Test & Repair

- Injector Pulling Call Out Service

- Collection & Delivery Service

- New Pump & Injectors For Sale

- Calibration Service

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