Passion gone, start talking! (4,4)
I believe the answer is:
fire away
'start talking' is the definition.
(phrase used to tell someone to begin speaking)
'passion gone' is the wordplay.
'passion' becomes 'fire' (fire is a kind of passion).
'gone' becomes 'away' (synonyms).
'fire'+'away'='FIRE AWAY'
(Other definitions for fire away that I've seen before include "Make a start or go ahead - using guns?" , "Informally, go ahead with all guns blazing" , "Go ahead, begin" .)