Buildcraft 1.8.9 pre 12

When I tried to pump some liquid with the pump it didn't work. I tried with the 3 engines types but none of them get any liquid. #

What setup are you using? What liquid are you trying to pump? Have you attached a lever to the engine? is the engine pumping? Do you have a fluid pipe attached to the pump?

What do you mean with setup?

I tried to pump water and yes, I used the lever to activate the engines and I made sure that engines were working as they got some temperature (I used builcraft 1.7.2 many time ago)

Updating to 7.2.0 beta (later than pre12) should help, it might be the case that pumps were broken in pre12.

I've just donwloaded the 7.2.0 from this website and the problem seems to persist. I downloaded also the last forge version.

https://gyazo.com/b2cfdf9fef5b99610efcd8a394ec5cf8

It's courious because when I turn down the lever the pump extend his own pipe.

You can use a redstone signal to disable pumps, so what's happening here is that the redstone signal is travelling through the engine and disabling the pump. Try moving the lever to a block next to the engine or running the engine through some kinesis pipes before going to the pump.

Ahhh I see, that's new! Now is pumping but I'm still not sure about stirling engines, after a while working they become black and stop working, why is that?

And I cannot connect a lava pipe to power the Stirling engines ?

Stirling engines only accept solid fuel. The only way to get lava into a Stirling engine is to first put it into a bucket and then you can put it in.

they become black and stop working

The engine is overheated and needs to be broken and placed again.