Preheat an outdoor grill to medium heat.
Rinse roast with cold water and pat completely dry with paper towels. For the dry rub, in a small bowl, combine ingredients for dry rub. Place tri-tip on plate or platter and season with kosher salt. Rub a generous amount of dry rub into both sides of meat. Let set for 10 to 15 minutes. Repeat rub 2 to 3 times until all seasoning is used.
While meat is resting between rubs, prepare BBQ sauce. In a saucepan over medium heat, combine pasta sauce, chili powder, dry mustard, Worcestershire sauce, and honey. Bring to a boil, lower heat and simmer for 15 minutes. Set aside about half the sauce for serving, use half as a mop while grilling.
Oil grill or spray with cooking spray. Grill meat about 20 minutes total for medium-rare, turning and mopping with BBQ sauce every 5 minutes. Transfer meat to a cutting board. Tent with foil; let stand 10 minutes. Cut diagonally across the grain. Serve with extra sauce.
If cooking on a grill pan, sear meat 5 minutes on both sides then finish in a preheated 400 degree F oven for 10 to 15 minutes.