This paper presents a run-time monitoring framework to detect end-to-end timing constraint violations of event flows in distributed real-time systems. The framework analyzes every event on possible event flow paths and automatically inserts timing fault checks for run-time detection. When the framework detects a timing violation, it provides users with the event flow's run-time path and the time consumption of each participating software module. In addition, it invokes a timing fault handler according to the timing fault specification, which allows our approach to aid the monitoring and management of the deployed systems. The experimental results show that the framework correctly detects timing constraint with insignificant overhead and provides related diagnostic information.