File field emptied on node_save
Well I answered my own question eventually.  The issue was the format for saving to this particular type of field 'file'.   I changed

$node-&gt;field_file_upload[$node-&gt;language][0]['value']=(array)$file_object;

to

$node-&gt;field_file_upload[0]['fid']=$file_object-&gt;fid;


For some reason the formatting that was given in other answers was not functional for me.  The file field type seems to be very particular about it's format, but it only NEEDS, the fid.  Once the node is loaded the full file array is loaded.

To answer longboardnode what I wanted was the array of data about the file that is stored when the file is uploaded.  Unfortunately node fields seem very picky about formatting.