The memo field will hold 65,536 characters.
I have no idea why it won't work for you when it did for me and other users.
Did you try

DoCmd.TransferText acImportDelim, , "temptable2", "C:\Access\TEST.TXT", False


So let's see if we can find out if your VBA code is working on the Import part.
After this line add this line of code

Line Input #1, strInput

Msgbox strInput

That should attempt to display the Data in the string.

If that doesn't work we can input a character at a time to see if that works using

Input #1, strInput

instead if Line input.