This comprehensive service repair manual is specifically designed for Jeep vehicles equipped with the 4.0-liter multi-point fuel injection system known as the RENIX system, covering model years 1987 through 1990. It offers a wealth of detailed information to assist both professional mechanics and dedicated DIY enthusiasts in understanding and servicing these vehicles. The manual provides in-depth coverage of every aspect of the RENIX system, from engine diagnostics and repair to bodywork, electrical systems, and components. It includes a wide array of diagrams, illustrations, and technical specifications, ensuring a clear understanding of the vehicle's intricate workings. Whether you're tackling a routine maintenance task or a complex repair, this manual serves as an invaluable resource, providing step-by-step instructions and troubleshooting guides to help you confidently diagnose and resolve any issues. With its comprehensive scope and detailed information, this manual empowers you to maintain and repair your Jeep vehicle with precision and expertise.

The Jeep RENIX 4.0 Liter Multi-Point Fuel Injection (1987-1990) system represents a significant step in the evolution of Jeep's powertrains. This system, found in various Jeep models produced between 1987 and 1990, utilized a revolutionary multi-point fuel injection system known as the RENIX. This system replaced the older carburetor-based setup, offering a major improvement in fuel efficiency, drivability, and emissions. The RENIX system featured a central control unit (ECU) responsible for managing fuel delivery to each individual cylinder, eliminating the need for a single carburetor. This allowed for precise fuel metering, ensuring optimal combustion and reducing fuel consumption. The system was also equipped with advanced sensors that monitored various engine parameters, such as air intake temperature, engine speed, and oxygen content, enabling the ECU to continuously adjust fuel delivery for optimal performance.

Beyond the technological advancements, the introduction of the RENIX 4.0 Liter Multi-Point Fuel Injection system brought with it a new era of driving experience for Jeep enthusiasts. The enhanced fuel efficiency and smoother power delivery made the Jeep more appealing for daily driving, while the improved emissions made it more environmentally friendly. However, the RENIX system also presented some challenges, primarily due to its complex wiring and the potential for sensor failures. While this system was a significant improvement over its predecessor, its reliance on intricate electronic components meant that maintaining and troubleshooting the RENIX system required specialized knowledge and tools. Over the years, aftermarket support and resources have become readily available for owners of Jeep vehicles equipped with the RENIX system, allowing them to maintain and restore these iconic vehicles to their former glory.