Accurate and simple time synchronization is a crucial requirement for decentralized wireless sensor networks (WSNs) to function well specially in harsh environments. The averaging consensus control protocol (ACCP), that uses single hop communication, performs well in such environments. This paper provides rigorous analysis of its time synchronization error which is by basic definition the difference between the gateway node time and the average virtual times of the other nodes in the network. Also, the paper presents a modified synchronizer protocol of the ACCP that further improves the precision of the time synchronization in WSNs. The improved time precision protocol is achieved reducing the forced response part of the time synchronization error. The proposed protocol is compared by simulations and by experiments and shown to achieve a synchronization error that is orders of magnitude less than these resulted from other known protocols which are. Finally, the proposed protocol was found to utilize the least memory and consume the least energy relative to some existing protocols.