I installed jedi along with some other packages via el-get the other day, and initially it all worked great (auto-completion, popup menus etc).
In the past few days, however, jedi has stopped working (i.e. auto-completion, popups and function argument suggestion no longer work).
I've discovered part of the reason for this not working is that, for some reason, auto-complete is not enabled on startup. I've tried adding (setq auto-complete-mode t) to my .emacs file both before and after el-get loads jedi, but despite enabling auto-complete, it still doesn't work for some reason. Instead, I have to enable auto-complete using M-x auto-complete-mode once emacs has loaded (I have also tried the suggestions here Emacs auto-complete-mode at startup, but that just throws a load of errors when emacs loads).
Besides this, when I type M-x jedi RET, some of the commands listed on the jedi troubleshooting page (such as jed:setup-keys) seem to be missing.
I also seem to be experiencing the same problems as this guy here: emacs-jedi does not find numpy completions, but I'm not sure if the two problems are linked.