Bought a new 5-pack of 0.5 coils. Pulled the old coil and screwed a new one in, no smoke. Tried another, same thing. It's like it's not making contact. I did notice the tip that makes contact with the base is shaped differently than the old one and has more holes (the old ones had one hole straight through, the new one has two cross-holes). What changed? What do I need to do to make it work?
Have you checked the scratch code ? Are they genuine coils ?
If you have an ohm meter, check the resistance between the center pin of the 510 connection, and base of your tank with the coil installed. If you read 0.5Ω, or don't have an ohm meter go to step 1. If you get an open circuit go to step 2.
Step 1: If your MOD had an adjustable 510 connector, raise the center pin by turning it counterclockwise one turn. If your MOD has a spring loaded center pin for the 510 connection verify that it works by pressing down on it with the tip of a pencil. Try the tank again. Try the tank on another MOD, as yours may be broken. You can try another turn or two if you have an adjustable 510 center pin if your tank works on another MOD. If you didn't have an ohm meter go to step 2, otherwise replace your MOD.
Step 2: Try tightening the coil into the base another quarter turn. If that didn't do it, try using the o-ring from the old style coil. Still no luck? You need to bridge the connection between the coil's center pin and base of your tank. Cut a 6mm (1/4 inch) square piece of aluminum foil. Hold the coil up side down, and press the foil onto the center pin. It will bend to match the pin's profile and keep it in place. With the coil up side down, screw the base onto the coil. This should work, if not, try a second piece of foil.