I was trying to set up an automatic lava-lake-to-obsidian harvester and ran into a big problem: The fluidic plenisher in this setup spits out a single bucket of lava and then completely stops working.

http://imgur.com/rOLqDxU

Instead of the expected behavior of detecting the block update below it and automatically placing another bucket, I had to stand there whacking it continuously with a configurator shift-right-click to reset it after each piece of obsidian was removed by the AE2 annihilation plane.

Additionally, when both the electric pump and fluidic plenisher were empty of lava, the advanced mechanical pipes appeared to still be full. When I added additional pipes leading to a portable tank, the lava contents appeared to redistribute among the pipes (without filling the tank either), but when I removed one pipe all of the lava vanished, so this is probably just a display bug.

I got about 90 blocks of obsidian out of the small surface lake I used to test this concept, but it would be really nice if it would work for pumping out and converting the hundreds (or thousands) of blocks of lava in some of the bigger deep cave systems (without manually clicking for every single block). It's understandable that it should shut off when finished if it's filling a large area, to avoid constant unnecessary block scanning. But a block update in the space directly below it seems like it would naturally demand a re-check of at least that one space, even if a full re-scan isn't performed.

I have the same problem (testing lava into water to create obsidian). It appears to only work one time I place the fluidic plenisher. I have to break and replace it. When looking at the sourcecode, it could be a problem with the "finishedCalc" value in mekanism.common.tile.TileEntityFluidicPlenisher, line 129. It doesnt seem to get reset to "false" after the first onUpdate()

Just implemented the change myself, thanks :)