well gents, thank you all for your assistance! here is what happened.
that "valve box" actually ONLY controlled the front yard. there were originally 3 valves in there, but one of them went NOWHERE. ha.
here is a before shot:
https://sphotos.xx.fbcdn.net/hphotos-ash3/532853_3164487114355_1330680285_32529363_740395893_n.jpg
here is after:
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/581258_3207133700493_1330680285_32544761_1997709743_n.jpg
the front yard is controlled by two valves. replacing all equipment with new stuff fixed my problem. i guess possibly ALL diaphragms (the original three) OR all valve bodies were messed up.... who knows at this point.
the "third" valve on the SE corner of my home controls a portion of the backyard.
I don't know where the fourth valve is that controls the other side of my house. i'm sure i'll find it when i need to
now... i guess the only thing i have to do is install a "back flow preventer"? man whoever did this install sucked.
you guys rock, thank you for giving me leads. now any leads on the back flow preventer?