The map says jump in ths pool and go down, but t pool is very dark and I hit the bootom, but I can't seem to find the palce where the map wants me to go.
Use your machete to get through the bottom of the pool. If you increase the brightnes of your screen, you should be able to see the bottom of the pool.
Light the fire bowl up and leap back into the well-lit water and spot the vines at the bottom. Cut them with your machete and dive through the exposed hole.
Found this information at:
http://www.the-spoiler.com/ACTION/Lucas.arts/infernal.machine.1.html)