No ideas other than make sure you're pushing the center of puller against the crankshaft, and not the center of pulley. I'm only familiar with the 3.2 and 3.5 where the pulley has a center that positively stops at crank snout, unlike the v-8s that most folks are used to messing with. In the case of the 3.2, 3.5, you have to place some kind of dummy spacer smaller than the threads of the crank bolt you removed. Hard to explain.