Try to resize the content size to huge numbers. I couldn't understand why my scroll view doesn't scroll even when its content size seems to be bigger than control size. I discovered that if the content size is smaller than needed, it doesn't work also.
self.scrollView.contentSize = CGSizeMake(2000, 2000);
Instead of 2000 you can put your own big numbers. And if it works, it means that your content size is not big enough when you resize.
The delegate is not necessary for scroll view to work.