Dr Joe
When I become frustrated with which component of my layout, TIU, WIU, etc. is causing a problem, I will often do the following.
I set up a temporary loop on the floor of the living room (the wife loves this) and remove my TIU etc. from my large layout and wire it up to the living room loop just to see if I can get the component to work correctly and make sure that there is not a problem with it or the way that I wire it up.
You then should be able to get a signal strength that is higher than 7 and just give you your confidence and sanity back and that you are working with good components to start with.
Sounds pretty simple and basic I know but sometimes it just helps to start over from the very beginning and then work back toward your problem.
Good Luck!
Woody