Di2 With Internal Wire Routing
 

My Di2 electrical wire runs internally in the frame. It rattles when riding rough roads. Can the wire be tightened in the frame as not to rattle inside?

You could pull the wiring back out and zip tie sections. Are you sure its your wiring? The Di2 shifters have been known to buzz/rattle on occasion.

This, and/or sticky velcro on the junction box worked for me.

It's definitely inside the frame. I wrapped electrical tape on any external wires/cables that came in contact with anything else so that it wouldn't make noise. The shifters are quiet.
I'll look into pulling the wire out.