Control car using pixhawk`outputs under qground control

#1

So i tried to control my car with pixhawk using spectrum DX8 under airframe Traxxas stampede vxl 2wd. So i connected servo for steering(2 MAIN OUTPUT) and motor(4 MAIN OUTPUT) and set SYS_AUTOSTART to 50002. Arming in QGround always succesful and i even can change fly mode (In instruction was writen that Manual works fine ), but when i tryed to pull throtle motor and servo won`t moving.