Use DCEN (Direct current electrode negative) for flux core....this means that the wire is negative. You will have to reverse the two welding cable connections under the wire feeder conver. DCEP is for solid wire (probably have to look it up on the miller site. Make sure you have FLOW out the nozzle. If you have junk in the gas line it might whoosh, then flow at a really low flow rate and burn welds. Some flux core wire is shielded with gas AND flux.
Hope this helps


64 & 66 GMC long fleetside 4x4
Cartwright, OK