Hi,

Without code I'm not sure there is a quick solution to that. You could define a calculated field for each value you want to use using the formula
=1/1/'field name'
which would return an error for each 0 field and that would not be plotted. You can suppress the errors from displaying in the pivot if you want.

As a side note, I would strongly recommend you use a different type of chart - probably a bar chart, which would make the text axis more legible than a column chart. It will be much easier to read and compare values than a pie chart.