Hi!
First of all, I have several others mods too (I don't know if there's ones that doesn't work with BuildCraft or not).
I want to pump the water into my Reaction Chamber (Techguns mod), so I use this mod to do it. I did everything as described. Water, pump, stirling engine, lava bucket, lever, golden waterproof pipes, etc. The pump IS working because it starts moving after I pull the level but the water IS NOT coming anywhere.
I really need help with that. Thanks xx

What version of buildcraft are you using? Also, how long have you left the engine + pump going?

I don't really know which version, I got it from 9Minecraft: http://www.files.9minecraft.net/index.php?act=dl&id=1511504960.
I've left the engine going for hours and it did nothing. I watched tons of tutorial videos of this and their pump started working and water started going immediately after they turned it on.

Try updating Buildcraft to the newest stable version available at https://www.mod-buildcraft.com/. 9Minecraft.net downloads can be unreliable.