The wick might have become to short to lead the fluid to the coil. After burning the crud off the coil no gunk should be left to make a burnt taste. You can see the coil and see if the crud turns to ash. If it doesn't turn to ligh grey ash covering the coil you migh have to dry burn it some more. If you see the light grey ash the coil is clean. It has to be the wick. Either too short or not clean.
But I re-wicked the wick with new silica and feel sure the wick is long enough to hit the coil; but will double-check now.