As already reported, ecryptfs does use your password to "unwrap" the mount key, and if you don't provide it when loggin in, it won't work.
If you do run
ecryptfs-umount-private to unmount the encrypted home, followed by a
mkdir ~/.ecryptfs/presets ; ln -s ~/.ecryptfs/presets/.profile ~/.profile and remount the encrypted home with
ecryptfs-mount-private. You will have a file in "~/.ecryptfs/presets/" called ".profile" which will be sourced on every connection. (If you it is unnecessary to be able to tweak this file with an mounted private home, you could just as well just create a real textfile called .profile in your unmounted home, instead of the softlink above).
The content of ~/.ecryptfs/presets/.profile (or unmounted "~/.profile"), could be something in the line of
ecryptfs-mount-private && cd ~ && . ./.profile
That will make sure your home is unencrypted, or otherwise ask you of your password to unencrypt it, change directory to your new mounted home, and source the ordinary .profile, which will set up your shell as you are accustomed to.