He isn't potty trained until he doesn't poop in his pants. He is half way done but not totally. Until he wants to do it, there isn't much you can do other then avoid a power struggle. I say keep the pullups on him all the time for now and let him take his time. It will save your sanity and stress and keep from messes constantly happening. Set him on the potty at the times you know he may or may have to poop, DO NOT ASK him if he has to go, set him on the potty and ask him to please try. If he goes celebrate! If he doesn't just thank him for trying.
He may understand the urge for peeing coming about but not pooping yet so he may just not be ready.
Really focus on him being a big boy, reward chart for every time he does poop in the potty and take away the underwear until he is fully there.
Many hate pullups however I honestly think we prematurely stick them in underwear then feel overwhelmed by messes and the stress when they have accidents. That actually will backfire as when it becomes stressful then it starts a power struggle, because you cannot make him poop on the potty. I trained both of mine with pullups and both when they went to underwear finally it was done 100%! I didn't deal with poop or pee on the floor or the stress of cleaning out underwear. When my kids were really ready it was all over with and such a huge relief.
Just step back, put him back in pullups tell him when he is ready to be a big boy and poop in the potty he can have his underwear back. If he is over three or three and a half, take away big boy toys and big boy priviledges and explain that until he proves himself as a big boy then he probably shouldn't have them. Tell him he can earn it back. If he is under three, give it time, boys take longer.