The universal emptiness, negatory, good old buddy, el zilcho.

[AlexMiller1994]

There was only blackness and that unviversal emptiness, negatory, good old buddy, el zilcho. Cold limbo. (Dead Zone by Stephen King)

Hi. Could you please tell me what does it mean?

In this scene, the character is in a serious car accident. He's flying out of the windshield and hit the ground hard. But I didn't understand what that sentence means, especially that last word "el zilcho".

 

[Myridon]

I would assume that "negatory, good old buddy" King's idea of CB radio lingo though the "old" is a rather odd insertion. "Negatory" was slang for "no" and they used "good buddy" a lot.
"El zilcho" is faux Spanish for "the zilch." "Zilch" means "nothing" or "zero."
zilch - WordReference.com Dictionary of English