FASS Diesel Fuel Systems
Motor Vehicle ManufacturingMissouri, United States11-50 Employees
FASS Diesel Fuel Systems designs and manufactures diesel fuel delivery equipment for heavy-duty vehicles, including fuel-air separation systems and electric fuel pumps. The company emphasizes quiet operation and long service life, with warranties ranging from several years for semi-trucks to a lifetime for pickups. Its designs aim to improve cold-weather starts and fuel flow by employing motors with high stall torque and durable materials. Much of the production process occurs in-house, with machining, assembly, and testing conducted under one roof and each unit subjected to more than 20 tests before shipment. Based in Marthasville, Missouri, the company operates within the motor vehicle manufacturing industry, focusing on the class-8 truck market and other commercial diesel applications. In May 2026, the company introduced a Universal Drop-In Series Fuel System for commercial diesel trucks.