Autocomplete is behaving as it is supposed to. It sounds like you want
all of the selection items to appear, not just the ones that start with
4, etc. If that is the case, you want a combobox, or maybe just a
select list. Either will be easy for users for a small number (say 3 to
20) select items.
Take a look at the Autocomplete Combobox demo. If it serves
your need "as is", you may want to use it. Don't try to
modify it - it will make you go insane. If you need a modified
Combobox, do a search and look at the many combobox plug-ins that are
available. They use options and can be easily modified.
If I've missed your requirements, tell us more.