Thats your problem right there!
A BC pump(which I guess that is) requires 10MJ per block of lava it pumps out. A Redstone engine only produces 0.08MJ/t at the red state. You really need a better engine powering that pump. You could use a Magmatic Engine or Electrical+Geothermal engine combo perhaps. Or if you have a MJ production back at base, you could simply make an Energy tesseract to send power to the pump.
The BC pumps speed limit is REALLY high, you just need to supply it enough power.
Also, remove the Liquiduct between the pump and the Liquid tesseract and place the tesseract directly against the pump. This will remove any bottlenecks once you got the pump running at higher speeds.