Cisco 2621 to other subnet

Do you have a return route on the pfsense box? You'll need to put in a route that says something like this:

Network: 172.16.1.0
Subnet Mask: 255.255.0.0
Gateway: IP address of the Cisco 2621 router on the 192.168 side

This is where you should have the IP address of the 2621 as a static and not a dynamic.