how to get an airlock out ov a 2002 transit van?

having cut out on me i thought it was out ov diesel so put £20 in and still wont start i hav cracked the 1st injector of tried towing it for a good 7 miles still wont start took the diesel filter of it was only half full so i have topped it up tried towing it again still no go any ideas would be gratefull im desperate to get it fixed for work