When something is not working well enough or it's performance leaves a lot to be desired, one can say: echele leña. This something is usually an object/person very old, outdated or not fit for the job. In the past, I believe, one would have to throw firewood (echar leña) to machines as fuel or to keep them working. For instance, if you turn on your laptop to show a video to one of your friends, but the laptop takes too long to start, your friend can say "échale leña".
Note that there's another expression "échale leña al fuego" which means to fan the flames of a fire...
Used in US as well
"Man, your computer is somewhat slow, échale leña."
The expression " Check out firewood " It's a colloquial way used in Colombia to insinuate that it is achieved with a slight push to rough-Hew. Used when tempers of two parts are warring about to discuss, and that with a light source is assembled the Trojan war. Encourage, stimulate, encourage, Excite, induce, instigate, cause, incite, tempt. ignite.