Saute onion in oil until tender, about 2 -3 minutes. Stir in syrup, vinegar, mustard, soy sauce and pepper. Let simmer gently for 10 minutes. Remove from heat and set aside.
Grill chops over medium-hot coals for 7-8 minutes, until nicely browned. Turn chops and brush liberally with glaze. Grill for 5 minutes more. Turn and brush with glaze for 3 minutes more, or until chops are done and nicely glazed. Do not overcook. Serve chops immediately.