In a large stock pot, add a tbsp of olive oil and cook onion and celery and sweat. Add green pepper and sweat. Add ground beef and cook until brown. Drain fat if needed.
In a large saucepan, boil water and add elbow macaroni, let water return to boil, cover, turn off burner, let sit for 8 minutes.
Add tomato sauce and cook for 5 minutes.
Add diced tomatoes, cook until it simmers. Leave on medium heat for 5 minutes.