Why isn't my custom texture showing up?

PP_START and END should work. Did you add them to the Patch Table and TEXTURE1 lumps? If not, open up Doom2.wad and copy and paste the files PNAMES and TEXTURE1. When they're in your wad, right click all the graphics in the PP section and add them to both the TEXTURE and PNAMES lumps.

try P_start and p_end if its a wall texture try f_start and f_end if its a floor texture

22 minutes ago, Lizardcommando said:

Thanks for the assist. I ended up adding the TX_START and TX_END for the new texture. That seemed to have done the trick.

Sorry if I'm pedantic, but that only works in ZDoom derived ports, I believe. A good solution if you're using a ZDoom format like ZDoom in Doom or Doom in Hexen or UDMF. But it won't work in something for Vanilla, Boom, Doom Legacy, Doom Retro, MBF, etc. I'm mostly posting this because people look these up and I want to be thorough 

Glad you got it working. 

Thanks for the assist. I ended up adding the TX_START and TX_END for the new texture. That seemed to have done the trick.

Oh, I did not know TX_START/TX_END was for ZDoom related ports only. Good to know for next time though.