Check your battery connections and ground. Most likely the starter is not getting enough juice to fire up.

hey im having a problem with my yota, its a 1990 pickup 2wd v6 it was working just fine on sunday,monday i went out to start it and it would not start all i hear is a clicking sound comin from the starter,i replaced the starter and i used my friends battery and it still doesnt wanna start,i still hear the clickin sound coming from the starter but still no start. i checked all my wiring its good,its an auto if that helps!