I have been doing many of the small airports around Eastern Iowa and have fairly good luck in setting  up a taxi route using the ATC button in WED from airplane to runway..but I downloaded an airport that I upgraded and installed a simple taxi route from ramp start to runway and it does not work for some reason.

 

The route goes from a grass ramp start to the runway with some bends over an asphalt taxi poly. When I add an AI plane it will start at the ramp start but then just goes the complete other way over the grass to the far end of the runway. No matter how I set the wind it goes to the far runway side ignoring the taxi route.

 

I have the ramp start set to props and miscellaneous and the taxi route has been validated as ok with no breaks or double nodes or splits.

Sorry, I can be of no help other than to suggest that there is a certain X-Plane site where your question would be answered, google is your friend :wink: