Preheat the oven to 350 degrees. Grease and flour a baking pan and set aside.
In a bowl beat the vegetable oil, sugar, eggs and water together until frothy.
Add the pumpkin puree, flour, baking powder, vanilla extract, pumpkin pie spice, and cinnamon and beat until everything is well incorporated around 3 minutes.
Pour the batter into the prepared cake pan and bake for 50 to 60 minutes or until golden brown.