In a large bowl, mix together hamburger meat and barbecue sauce. Season with salt and pepper.
Shape mixture into 4 large patties. Place a slice of pineapple on top of each. Crisscross 2 bacon strips around each burger, and secure with toothpicks.
Brush oil on grate. Place burgers on grill over medium low heat. Cook, covered, until the burger is cooked through. Turn often to avoid burning the bacon.
