Start your Grill on 'smoke' with the lid open until a fire is established in the burn pot (3-4 minutes). Preheat to 250F.
Place the roast beef in an aluminum pan. With your Meat Injector, inject the beef broth throughout the roast. Pierce the roast with the needle and inject the broth as you pull the needle out. Make slits about 1/2 inch deep with a sharp knife all around the roast and push the slivers of garlic in each hole. Season the roast with the onion powder, salt, and pepper. Pour the rest of the beef broth into the bottom of the aluminum pan.
Place the entire aluminum pan in the , making sure that the fat side of the roast is up. This will allow the fat to melt through the meat as the roast is cooking.
Smoke the roast beef for about 4-5 hours, or until the internal temperature reaches 155F. Baste every hour to keep the meat nice and tender.
Once the internal temperature reaches 155F, remove the roast beef from the grill and wrap in aluminum foil to let rest for about 20 minutes. Slive against the grain and serve with roasted vegetables.