Add the cake mix, pumpkin, eggs, melted butter, water, vanilla, cinnamon, nutmeg, cloves and salt to a large bowl. Whisk until combined, some chunks of cake mix are ok, don't over mix.
Spray the slow cooker well with non-stick spray.
Pour the cake batter into the slow cooker, spread until smooth.
Add the pecans on top of the cake batter, arrange them in a design if desired.
Cover and cook on HIGH for 1 hours and 45 minutes. (see notes)
After the cooking time is done, turn off the slow cooker.
Spoon the cake into bowls and top with ice cream, if desired.
I keep an eye on the cake towards the end of the cooking time. If the slow cooker insert is askew and closer to one side of the warming device, it can burn there, check for that and move it away from that side.