Funky/weird/nasty taste could be a lot of things. Yes, an oil or grease coating on the wire might be the problem. Alternatively, it could be the wick, or something on or in the wick (like an oil of some sort) or the legs of the coil could be getting hot and burning/scorching the o-ring (if you're rebuilding a protank head). It could even be the juice (have you tried this juice in another device?).