I have an ender-thermic pump set up connected to a magmatic dynamo:
It works as expected, once started with a bucket of lava in the dynamo-the pump powers the dynamo, and the dynamo powers the pump.
Periodically, it just...stops. The lava production ceases. The dynamo does not run out of energy, yet somehow appears to be the cause, as breaking and replacing the dynamo restarts the system.
I know there was a precursor to this device: the magmatic engine, which apparently overheated quite easily. However, the corresponding page for the magmatic dynamo, which I'm using, mentions nothing of that sort.
I've read that the ender-thermic pump is supposed to load the chunk it's on automatically, which brings up the question of whether the dynamo is being unloaded by accidentally straddling a chunk boundary. It is not:
Those red lines indicate the chunk boundaries, and my entire setup is within the cobblestone structure you see, which is clearly all in a single chunk.
What's going on here? A bug? Undocumented overheating?