Use ListPointPlot3D
:
data = {{1100, 1000, 90, 100}, {1200, 1000, 89, 110}, {1300, 1000, 88, 120}, {1400, 1000, 87, 130},
{1500, 1000, 86, 140}, {1600, 1000, 86, 150}, {1700, 1000, 85, 160}, {1800, 1000, 84, 170},
{1900, 1000, 84, 180}, {2000, 1000, 83, 190}, {2100, 1000, 82, 200}, {2200, 1000, 81, 210},
{2300, 1000, 81, 220}, {2400, 1000, 80, 230}, {2500, 1000, 80, 240}, {2600, 1000, 79, 250},
{2700, 1000, 78, 260}, {2800, 1000, 78, 270}};
ListPointPlot3D[data[[All, {1, 2, 3}]]]
But with y being constant, it's not a very interesting display.
And my point about needing y to vary is that IF the formula depends on y you can't get there from here if y doesn't vary. It might end up that y isn't used at all in the formula but one can't know that either without varying y.