.. Make the engine work again

Correct. Explore more until you find gas.

First, talk to Piscilla by walking up. Then, begin to find Butcher's lab. Come back when you are in a cryo room.

There's a gas canister in the cryo room ( It is there far left. If you don't see it, load the game fullscreen or different resolution. ) .

Pour the gas into the admission valve and pull the lever. The engine starts working and you got electricity.