It would help to know your location.

Could you describe the distinctive characteristics? Is it woody or soft stemmed?  Can you send a picture of the entire plant?  

Entire Plant

It appears that you have some kind of passion fruit plant growing in yojur garden, possibly passed on by seeds.  The passion fruit, or passiflora, grows well in your area, and likes warm, wet locations. once established it will grow fast and bear fruit.  From the flower you could identify the genus, possibly take a sample to your local extension office for a definite identification.

I would like to offer a different opinion on the likely identity of your mystery plant.  I think it is a species of Piper (Piperaceae), which is a very large (1-2 thousand species worldwide) genus of mostly tropical plants.  It includes the "black pepper" of commerce.  Leaves are variable, but your plant looks like most Piper species, and the tail-shaped inflorescences with many tiny flowers are highly characteristic.  There are many different species of Piper in Ecuador, so you will need to consult a local expert to take this further.