Heat coals or gas grill for direct heat. Cut four 18x12 inch pieces of heavy-duty foil. Cut each squash lengthwise in half; remove seeds.
Place squash half, cut side up on each piece of foil. Sprinkle with salt.
In small bowl mix butter, orange peel and 2 tablespoons of the maple syrup. Brush over squash halves.
Fold foil over squash so edges meet. Seal edges, making tight ½ inch fold; fold again.
Allow space on sides for circulation and expansion. Cover and grill packets over medium-low heat 50 to 60 minutes, rotating packets ½ turn after 25 minutes, until squash is tender.
Place packets on plates. Cut large X across top of each packet fold back foil. Sprinkle pecans over squash; drizzle with remaining 2 Tbsp maple syrup.