Place a pan of soaked hickory chips on grill burners and preheat one side of grill.
Scrub potatoes under water with a vegetable brush. Cut into quarters, lengthwise. Coat with the olive oil, salt and pepper and place on a baking sheet.
Put baking sheet on opposite side of the grill, not over direct heat. Turn grill to low and cook for 15-20 minutes. Turn potatoes and continue cooking/smoking until fork tender, cool to room temperature.
Meanwhile, in a large bowl, combine mayonnaise, sour cream, celery, salt and pepper.
Cut potatoes into bite-sized pieces and add to dressing along with half of the bacon, cheese and green onions. Lightly fold vegetables into dressing to combine.
Cover and refrigerate for several hours. Garnish with remaining bacon, cheese and green onions and serve.