Instead of:
clearInterval(ciclo);
setTimeout(startSlidercicle(), 3000);
or:
clearInterval(ciclo);
setTimeout(startSlidercicle, 3000);
I changed the code to be:
clearInterval(ciclo);
startSlidercicle();
And now the slider just works fine. I think that, in the first two proposals, every time I click on the div, a new function is created, "overlapping" over the existing cycle and, thus, it looks like the slider speeds up, but its just one cycle starting over another.