Make a lengthwise slit along the inside curve of each banana – Do not cut all the way through! Gently open to form a long hollow and then place each banana on a large piece of foil. Combine the marsh mellows, chocolate chips and pecans together, separate into four equal portions. Stuff each banana with a portion and seal foil around the banana; Preheat grill to medium and barbecue 8 minutes Carefully open the foil packs - chips should just be starting to melt