I pulled the electrical connector off the CDCV. I tried both with the ignition on/car off, and car on and there was no voltage across the terminals. It may have briefly pulsed on when I turned the key, unfortunately I didn't have a second person and I can't be in two places at once -- but it didn't seem to ever turn on. I believe that passage is normally open and closes when energized, which explains why I was seeing a leak through the vent. Question is, is this normal behavior or do I have another problem? Do I have to just put 12V across the CDCV and re-test?
Also, as for the fuel pump, yeah, I was replacing the tank so only that metal ring was ugly, and I think that I might even have gotten a new one with the tank. The question is, is it possible to assemble the thing wrong and create the fuel cut symptom? I just saw that new plastic piece at Rockauto for $28, might have been wise to put that in, I know I didn't do that.
Looking at the service manual it unhelpfully says:
Connect WDS to DLC-2
Turn ignition on
Close the CDV using ON-BOARD DEVICE CONTOROL [sic] function.
NOTE: The CDCV is closed for 10 minutes UNLESS the following any action is done [sic]:
-- The engine is started
-- The ignition key is turned off.
-- The fuel tank pressure sensor signal exceeds 6.43 kPa.
Since I don't have a WDS (whatever that is) (and I bet most independent mechanics don't either) I guess you either have to jury rig it with a power supply/battery or go to a dealer. Great!