About Us

Welcome to L&J Diesel Service Inc.

Since 1968, L & J Diesel Service, Inc. has steadily grown in size, customer base and diversity. Our reputation is wide spread as an innovative company of dedicated professionals who can be relied upon for superior craftsmanship, quality product lines and responsive service.

L & J Diesel Service, Inc. began in Miami with one employee, the founder Luis M. Cueto, and only one test stand. The company moved to Jacksonville in 1974 and grew rapidly, relocating in 2014 to a new specially designed and fully equipped facility.

Our growth and diversity is continuing with many employees and more than 10 test stands including a high tech computerized 100 hp EPS 815 Bosch calibration test stand for the most powerful and accurate testing available anywhere.

Today, L & J Diesel Service, Inc. is the largest, most diverse, and complete independent diesel engine parts shop of its kind in the southeast.

Mission Statement

Our Mission is to continue to provide our customers with competitively valued, quality products and service, at a level of excellence which establishes the standard for our industry.

This will be accomplished by being sensitive to changing customer and market needs, and positively responding to these changes with innovative approaches developed by involved employee/owners.


Our Philosophy is that we are all important members of a team of employees/owners that will, by utilizing our individual strengths in a cooperative group effort, achieve our Mission and Purpose.

We encourage a climate of open communications for sharing of ideas, and in so doing, provide opportunities for individual growth, increased responsibility, and personal satisfaction.

Values and Beliefs

We value and believe in a dedication to continued excellence, achieved by self motivated employees/owners, and will continue to exert our best efforts in all that we undertake.

We believe that the best opportunity is for employees/owners to share in the rewards of our companies' growth.


"Dieselogic has pioneered advanced technology to put the 'Service' back into the Service Dealer’s hands, leading the way by achieving cleaner burning diesel fuel systems with Dieselogic test equipment, service, parts, and more!"
-O. Cueto, L & J Diesel Service, Inc.

Dieselogic is the Research Division of L & J Diesel Service, Inc. (a Diesel Service company, in business for over 50 years). We have developed user friendly testing machines which work with equipment most shops already have. With our cutting edge technology in test equipment, we are continually developing methods to reduce the environmental impact of the existing diesel engines.

We don't stop at just supplying equipment. We also engineer diesel engine parts and components for fuel injection systems. We specialize in revitalizing existing older test equipment by providing adapting instruments and Retro-fit Kits that enable our customers to generate new sales dollars from out-of-date test equipment.

Most of our products are designed based on feedback from our industry. In developing our test equipment we focus on continuous improvements in fuel efficiency and emissions. If you want dependable diesel engine parts or equipment, whether it’s our standalone NEO, ZF3 Test Stand, Universal Cam Box, CD3 Retro-fit Kit or a Dieselogic remanufactured injector, we are eager to serve you.