Injectors

Hi, just wondering three injectors are very bad in my car. I was driving today and it started making a lot of noises i pulled in and turned it off and it stayed running for a few seconds. i drove again for a bit and now it will not start at all. i tried bleeding the injectors and no diesel is coming out? It is a Zetec S 130 and i was wondering can 2.2 st injectors fit and work instead of the ones i have in it? Could it also be that i have a bad injector pump that there is no diesel getting to them? Any help would be great thanks.