Eloqua Bulk API import definition can include a maximum of 100 fields. If you specify more than 100 fields, the task fails to create import definition.
Eloqua Bulk API export definition can include a maximum of 250 fields. If you specify more than 250 fields, the task fails to create export definition.
Note: The fields you map in Field Mapping tab of a synchronization task correspond to the fields in Eloqua Bulk API import or export definitions.