Blender fbx import from ascii format

If you have Visual Studio installed try to open the original file then save it and import in Blender. This should work.

For some reason Blender import doesn't support FBX models that are serialized to text.

As a workaround the model can be changed to binary FBX model and imported to Blender. At least I am able to use Autodesk FBX 2013.3 Converter even I don't have any other Autodesk software installed.

Other option that might work is to use Bos FBX Importer.

PS. If you want to export FBX models from Blender and be able to import them again, you can choose version: FBX 7.4 binary not FBX 6.1 ASCII in the export settings panel.

Unfortunately I can't comment yet but here's an update to maZZZu's answer:

The Bos FBX Importer will also not open ASCII .fbx files, however Autodesk's FBX Converter still does. Here's the updated URL: https://www.autodesk.com/developer-network/platform-technologies/fbx-converter-archives