Board Thread:Manga/@comment-7278867-20170405013703/@comment-31655854-20170406113514

Jaegermeister Braun wrote: Junior0124 wrote: Actually what are you talking about, Grisha never got the chance to try in the first place. He went straight to Eren after he ate Frieda. Grisha wasn't able to use it as eating doesn't work and he thought he wiped out the royal family so there was no one to for him to use it with. Eren's had the co-ordinate ability ever since he ate Grisha but wasn't able to use it until he touched Dina, that's what was made clear in chapter 89 after the correction.

It doesn't state in the manga that Grisha tried to use the coordinate does it. His 13 years were probably already up at that time as well. Although I think that the manga does state that Kruger didn't know that only people of the Royal bloodline could fully use the coordinate so maybe Grisha didn't know that either which is why he tried to wipe out the royal family. Ah who knows..