I haven't tried it empty but I guess if thats one way to tell I will try that. Just a pain in the .... getting rid of all that juice to try it.
its the only way to check if coils are correct. you cannot really check for properly firing coils with the juice in the tank. this is usually done after coiling the wick and before adding juice. this is how to coil a wick..... oxidize wick/ coil the wick after annealing your wire/ wrap wick/ attach leads/ set voltage to a low setting(3.0v)/ pulse button on and off, then again, then again, each time increasing the lenght of hold on button, after a couple of times you will see the coils firing up, hold down button a little longer, and watch the coils light up,then increase voltage in even increment then repeat.. if any are glowing more then others, hot spot, short, no good. / take a toothpick or something to prod the wires above and below the red coil, if you persist at this you should be able to even everything up by proding the wires while they are actually glowing, but just give some time for things to rest, dont keep the button pressed for to long. after you get every wire glowing evenly, stop and wait....... wait ...... then try again check to see if still good if so wait.... wait.... check one more time, still good add juice, check resistance and vape... now if you cannot work out coils no matter what you do, it could be that either the coils are to loose, to tight, to much tension, or just a bad wick not done properly... it can be so many things. it takes time, lots of time and reading differnt posts and threads and videos... be patient but you will get it and when you do it will be all worth it.