Sauté the bacon in the cooker until it has reduced its fat.
Add the onion, garlic, and green pepper and cook until the green pepper is softened.
Stir in the flour, then add the potato, celery, tomato, clam juice, bay leaf, salt, and pepper.
Close the lid and bring to pressure. Cook on High for 5 minutes or Low for 9 minutes. Release the pressure and open the cooker.
Discard the bay leaf. Stir in the clams and serve. The soup gains in flavor if it sits a few hours at room temperature or is refrigerated overnight.