UpTime Diesel Generator Predictive Maintenance System is an IoT-based solution designed to prevent unplanned downtime in diesel generators through real-time monitoring and predictive analytics. The system employs ESP32 microcontrollers with multiple sensors to continuously track critical generator parameters including temperature, vibration, sound levels, oil pressure, fuel consumption, gas emissions, and electrical current. Using a hybrid edge-cloud architecture, sensor data is transmitted through PHP backend scripts to a MySQL database for processing and analysis. The cross-platform Flutter mobile application provides maintenance teams with real-time dashboards, historical trend analysis (1-hour, 1-day, and 10-day intervals), and predictive alerts for potential component failures. By calculating Remaining Useful Life (RUL) for critical components, the system enables proactive maintenance scheduling, reducing both unplanned downtime and maintenance costs. Integrated with Firebase for push notifications, the platform ensures maintenance teams receive timely alerts to address issues before catastrophic failures occur.