Take your igniter and put a glow plug in it and see if it glows, and if it does, does it glow brightly. I'm guessing your engine isn't broken in yet. Engines can be VERY hard to get running until they are fully broken in. Do you have a pull start on this truck? What size engine is in it? What brand and nitro % of fuel are you using? Have you done any adjustments to the idle, low speed needle, or high speed needle? It may help to use a hairdryer to warm up the engine a significant amount before trying to start it. This may help.