When simulation is loaded pressure everywhere is zero. It messes up some engines and other stuff, some engines just don't work without pressure and won't launch after they are loaded. Some other things need time for pressure to rise before they can work.

Fix it please.

@Catelite
I like minimalism. I think machine that can work without fan whol or pump is better, than machine that has a lot of stuff.

Look at his engine for example, uses only pressure from explosion and nothing else