If I put all the machines in place first, and the steam engine becomes a modular steam engine, and then add fuel to the boiler, the modular steam engine will not use the steam from the pipe, and copying and pasting the modular steam engine will not work properly

Should be fixed in the new version - collision boxes were pretty far from the edges, which worked fine but possibly some update to the base game made it too far for the pipes to connect.

You MAY have to pickup and replace some old quad turbines/engines to get them to connect, though they seemed to migrate fine for me.

I am a multi-mod player, and this problem still exists. After I use this mod again, the first quad steam turbines can receive steam normally, but the double and quad steam turbines placed next cannot receive the steam in the pipes.