Calicool gave you some pretty good advise also, so I really can't offer anything to you. Is the cap that you installed the spektrum recommended one? Do you ever need to rebind them together? Is your spektrum system an older unit they may not have received their updates? I know I had to send my units in. They were first and second generation units a few years back. Other then getting the wire up and straight I got nothing else for you. Good luck.
Team ORCA / ORCA USA / Pro Spec
Serpent America / Team Serpent S411 ERYX / On Point Racing OP12C, S120 / Xceed Products
Hangar 30 / Seattle RC Racers
Fasttrax Racing Series / NORA On Road Series