I have to remove my harmonic balancer/crank pulley, but cannot hold it to loosen center bolt. Have tried strap belt but it just slides in strap, tried placing wrench on ground and touching starter, but just lifts car. Any suggestions?

 

Bug fat impact wrench will do it. Or 1/2 dive breaker bar and socket, whack handle with a hammer. Make sure you are turning the bolt counter clockwise.