I have to heat the bed n nozzle manually Everytime before printing

I'm using self made prusa type printer (with marlin, slic3r) the prints are just great ,but a strange problem,before starting to print from my sd card (which I always do) I've to manually heat the bed and nozzle from my lcd controller.I have tried cura it makes the heatbed working but not the hotend Please someone help.

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Newbie with scratch built Prusa i3 with Ramps 1.4 , arduino mega using marlin firmware.

put these in your custom gcode, stat gcode

{IF_BED}M190 S{BED}
{IF_EXT0}M104 T0 S{TEMP0}
{IF_EXT0}M109 T0 S{TEMP0}

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Prusa i3 upgraded with some of my own parts and E3D v6 hardened steel nozzle, large 400mm3 enclosed printer in to revision 3

Tried it, don't work