Combine chili sauce, bourbon, mustard, garlic, soy sauce and maple syrup in large plastic bag or large glass baking dish. Marinate the pork loin in the sauce for two or more hours.
Prepare grill for medium heat.
Remove pork loin from marinade, reserving marinade in small sauce pan. Place marinade over high heat until reduced and sauce thickens, at least 15 minutes.
While sauce is cooking, grill pork loin until a meat thermametor reads about 135 deg F - remove from grill, cover with foil and let sit for 10 minutes before serving.