Preheat oven to 350 degrees F. Generously grease two loaf pans, or line with parchment paper.
In a large bowl, stir together 2 cups sugar, 1 cup brown sugar, 1 cup vegetable oil, 2 teaspoons vanilla, 4 eggs, 1 15 oz. can pumpkin puree and 2/3 cup water until smooth.
In another large bowl, whisk together 3 1/2 cups flour, 2 teaspoons baking soda, 1 teaspoon salt, 1 teaspoon ground cloves, 1 teaspoon pumpkin pie spice, 1 teaspoon cinnamon, and 1/2 teaspoon ground nutmeg.
Add the pumpkin mixture to the dry ingredients and mix until incorporated. Do not overmix. Divide the batter evenly between the prepared pans.
In a small bowl, stir together the 6 tablespoons pepitas, 1 tablespoon maple syrup and 1/2 teaspoon vegetable oil. Sprinkle the pepita mixture over the batter in the pans.
Bake for 55-65 minutes, or until a tester inserted in the center comes out clean. Cover with foil partway through baking if the tops are becoming to brown. Remove to a wire rack to cool completely before slicing.