Mix together the olive oil, soy sauce, white wine vinegar, honey, Dijon mustard, salt, and garlic powder in a bowl.
Cut up the pork loin and place in a ziploc bag, pour marinade over the pork, reserving 1/4 Cup for later use. Place in refrigerator for at least one hour. (I prefer overnight.)
If using wooden skewers, make sure to soak for at least 30 minutes before using.
Cut up the pineapple.
Begin making the skewers by placing pork on skewer first, followed by pineapple.
Preheat grill to medium-high heat and spray with grill cooking spray.
Place skewers on preheated grill and cook for about 10-15 minutes. Brush with marinade and turn over. Brush with marinade and cook for another 10-15 minutes, or until pork is done. Pork should be cooked to an internal temperature of 145 degrees.