Unable to do Time Machine backups from MacBook Pro on Mavericks
Troubleshooting Time Machine against a Time Capsule is a very slow process.

I like to just get a new USB drive and let Time Machine back up there and you can know if the problem is the Mac or the destination.

Doing that will help isolate what is causing the delay. I would also use a second machine to go into the Time Capsule and delete any "in progress" backups while your "problem Mac" is doing it's first backup to the USB drive.