You cannot e-file a past year amended return. You have to send those past year amended returns by mail. Use a mailing service like certified mail so you will know the IRS received them since you will be waiting for a long time for them to be processed.
Do not expect quick results from amending. It can take four months or more for the IRS to process an amended return.
You can watch for information here:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**