Okay, so here's the set-up. 2 combustion engines fueled with ethanol from an ender tank and cooled with water from a nearby aqueous accumulator. The combustion engines are running and storing energy (maxed at 10k MJ). They are connected to the fabricator via wooden kinesis pipes that are then connected to golden kinesis pipes that are connected to the fabricator. I've attached an image so you can see what's going on. I'm assuming the problem is on the output side of the power plant but the pipes are all connecting to their respective blocks. What am I doing wrong?
You're trying to use Buildcraft engines and kinesis pipes, which went back to MJ in the 1.12.2 builds, to power a Forestry machine, which last I knew uses RF (well technically Forge Energy, but same thing from a player standpoint). I don't know why the kinesis pipes still connect to the fabricator (or what mod is giving you a reading in MRF for the kinesis pipe you're looking at), but I think you'll need either a converter block or some power sources and transfer blocks from RF mod(s) (e.g. Thermal Expansion Steam Dynamos, Forestry Peat Engines, or Ender IO Stirling Generators as the power sources, and Thermal Dynamics Fluxducts or Ender IO Energy Conduits to transfer the power to the fabricator)
Edit: possible alternative explanation - does the fabricator have any sand or glass in the left slot to melt? The fabricator only heats up when it does - it doesn't pre-heat.