good point nickj, i think its turbulence too, but i also dont know how much volume the malpassi can take and my fuel pump came form tanks inc in the states as a in tank kit with out any specs on volume.
i could try fitting a valve in the line but not sure how to monitor it, as you cant gauge the flow rate.
yes tim13 its plumbed on the outlet side of the fuel rail and that bottom outlet goes back to the fuel tank in a 3/8 aluminum line
i haven't tried hooking a vacuum line to the top.
the trick here is that it does it either way with engine running and off, so its got to be flow related, maybe there is sparp edges in the regulator that are causing it, wont know till i pull it apart.
kind of expected this to be a good reg as Palm side use these on their rally cars