Training A Hard Headed Chihuahua….. Plz Help!!?

nugget aka “nug the luv bug” is a chihuahua and is 1yr, 2m old and weighs only 3 pounds. he is the hard headedest dog there is that could be trained. i got him when he was 2-3 months old. he was pretty good about peeing on the puppy pad, but not pooping on the pad. he stays inside along with my 12 yr old cockapoo that is fully trained. it only took about 2 wks to train my cockapoo, but my chi that’s a different story and a year later, i am still spraying cleaner to clean up poop and pee. now my house is starting to smell. i have tried the crate training, but didn’t get any results, only had to clean that also. he goes out when my other pooch out as well as not with her. the little fart doesn’t even go off of my porch to do his biz. now that he’s older, he won’t use a pup pad, he will hike that lil leg instead. i am to the point of putting a bandade on his little dinger, lol.. but that won’t stop the pooping. there’s not a training shop anywhere near me, so what can i do???
plz help…