Well, too much communication occurs when you, the project manager, are routing information to the wrong people.
For example, sending detailed project reports to stakeholders, who only want to know the progress of the project, and if there are any substantial obstacles facing the project.
Another example of over communication is communicating the same information over and over again in different forms (emails, phone calls, meetings, etc...). This will make the people on the other side think that you think they're dumb (why is he sending us this thing over and over again, does he think we're stupid?).
In order not to have a communication overflow in your project, ensure the following:
- Do not communicate the same thing many times (it's OK to communicate it a few times, but not many times)
- Communicate only the right information to the right people