Crumble meat to a fine texture with a fork, if necessary; drain excess fat. Stir in the mustard, vinegar, sugar, water, Worcestershire sauce, celery seed, hot pepper sauce and ketchup. Mix well reduce heat to low and simmer, uncovered, for 35 to 40 minutes.
Chili is thick, filling, and can stand as a main on its own; it's spoonable. Coney sauce is traditionally very thin: You should be able to drizzle it on the hot dog, and if spooned on a plate, it will spread everywhere. Chili on a plate will look like a mound, while coney on a plate will look like a mess.
The "Coney Island hot dog" actually originated in Michigan, not Coney Island, New York. At least three restaurants purport to have created the famous hot dog, two in Detroit, Michigan and one in Jackson, Michigan. There's also a Cincinnati version. The hot dog is topped with Cincinnati chili, shredded cheese, mustard, and some chopped onion.