Place potatoes and ½ cup water in a large microwaveable bowl. Cover and cook for 10 minutes or until potatoes are just fork tender but not falling apart. Drain.
In a large bowl, combine mayonnaise, vinegar, sugar and mustard. Season to taste with salt and pepper. Add potatoes, bacon, celery and onion and stir until evenly coated.
Place two pieces of 18x24-inch heavy duty aluminum foil on top of each other. Pour potato mixture onto foil. Fold and seal foil edges together to form a packet. Grill for 35-40 minutes, turning every 10 minutes.
During the last 10 minutes of grilling the potato salad, add sausages to the grill and warm according to package directions. Serve with potato salad.