Put the vinegar and wedges in a medium pot and bring to a boil. Reduce heat to medium and cook for 10 minutes or until the potatoes are a little tender, but not fully cooked.
Remove the pan from the heat and let the potatoes sit in the vinegar for 20 minutes.
Preheat the grill to medium-high heat.
Drain the potatoes and add the oil, salt, and pepper.
Place the potatoes directly on the grill grates and cook for 10 minutes on each side.