Asking a deceased wali to make dua for oneself

When one goes to the graveyard, then the sunnah practice is that one recites verses of the Quraan Majeed and conveys the reward to the deceased. Making dua to Allah Ta'ala for one self, the deceased and the ummah while standing at the grave is also permissible. However, asking the deceased to make dua for you is not established in the sunnah. Therefore, one should refrain from this.

And Allah Ta'ala (الله تعالى) knows best.