Since a pension is considered Unearned Income, it would not qualify for a Foreign Earned Income Exclusion.
However, if you paid tax on your Foreign Pension Income in Ireland, you could claim a Foreign Tax Credit.
US citizens are required to report their 'world-wide income' to the IRS.
Click this link for instructions on Reporting Foreign Pension Income. There are two different ways to do this; however, the end result is the same.
Here's how to claim a Foreign Tax Credit.
This IRS link has details on Foreign Pensions and Annuities.