I found the answer to this and wanted to post this for anyone else that
may need to do this.

nickgrattan.wordpress.com/.../filtering-views-by-time-and-
date/#comment-635

Your observation is correct, per default the DFWP filters  by date  only.

I have no way to check this out at the moment, but out of the top of my
hat, you need to do the following:

- switch to Code view

- find the data  source

- open the tag property task pane

- and change the selectcommand CAML from
<Value Type="DateTime"> to
<Value Type="DateTime" IncludeTimeValue="True">
for all date fields  that needs to be filtered by date/time

If you need more info Google up IncludeTimeValue="True", it was blogged
before.

Thank you Jonathan Scott!

This worked perfectly.

Simply adding IncludeTimeValue="True" to my SharePoint list is now filtering my results by time.

Much appreciated!