Just a preface : these items are not kept when you save, so you need to grab all 3 in a single segments and without dying. I recommend having the max level card (Class A / Blue) before trying to gather those, with a SMG fully upgraded to deal with the army of crabs at the end.
Fuel is located in the red area (from the start, take the elevator down, left and down again). Right at the start that area, you go all the way up the first elevator, down the second elevator, then the one on the left (requires green keycard) and it should be there.
Engine and Radio are located in the green segment of the map (from the start, go right and ignore the first elevator, go down all the way at the second elevator, then fully to the right and through the blue door).
When you are there, call up the elevator and go to the last floor, keep going and take the second door, you will find the radio.
Go back to the elevator and go down the 2 floors and into the first door, you can enter a dialogue by pressing E near the screen.
(As of right now, I don't think you can get the engine any other way), ask for the engine, accept to start the self-destruct sequence.
Go right, take the door and immediatly right, get pass the enemies and the engine should be in the room.
Now you can rush back to the start and activate the contraption.
