This manual covers Mazda BP-DOHC engines, encompassing all models, years, and trim levels. The BP-DOHC engine is known for its robust engineering and reliable performance, featuring an inline 4-cylinder configuration with a DOHC valvetrain and electronic fuel injection. Its versatility, with options for naturally aspirated or turbocharged variants, makes it a capable powerplant for various applications. This comprehensive guide is designed to provide all necessary information for understanding and working with this engine. The purpose of this manual is to serve as a definitive resource for the service, maintenance, and troubleshooting of Mazda BP-DOHC engines. It includes detailed step-by-step repair procedures, diagnostic information, electrical service procedures with wiring diagrams, and hundreds of illustrations, diagrams, and photos to aid in understanding. Essential technical specifications, including tightening torques and fluid recommendations, are also provided. This manual is an indispensable tool for owners, mechanics, and technicians seeking to maintain the optimal performance and longevity of their Mazda BP-DOHC engine.