If a BC pump cannot emit (forge) fluids directly into an adjacent tank or pipe it is usuallly because you have 'incompatible' versions of binnies mods, forestry and buildcraft - or some other mod that bundles the buildcraft api.
First, update to the latest versions of all the mods that might include Buildcraft integration and retry. If still broken then:
strip your modpack down to just buildcraft, create a test map, and verify the pump works (it will).
Add mods until the pump stops working.
Notify the author of the last mod added to fix their $#!^.
