auto ctrl-P in Vim

Hi,

My desire is to make vim automatically open complection menu ( like when I hit ctrl-P ) after I've inserted 3d symbol in the word. I've tried to search plugins or scripts, but didn't find anything simple/convinient yet. 

I'm not familiar with writing vim plugins or scripts, so I can't imagine how to do it by myself. Can you help me and point out if there is anything already developed? Or what should I add to my vim settings?

Thanks in advance.

Alex.