Hopefully I am posting this in the right place. I'm new here today, looking for any ideas / help as getting very frustrated with my E320 CDI engine. 1. Have removed two injectors to fit new seals. 2. Bought injector puller from ebay, pulled injector out but made hole in rocker box cover ! 3. Lost tiny ball bearing from inside of injector. 4. Bought replacement injector and fitted. filled hole in rocker box cover. Now engine shows no sign of firing at all. Any ideas please on why this might be ? thanks in advance from thoroughly frustrated, Essex !!