Since minecraft uses his Tessellator to render stuff, glColor4f can not be used for that.
WHat you have to do is creating an instance variable of Tessellator and then calling the setColor-method like this:
public void renderTileEntityAt(TileEntity te, double x, double y, double z, float scale) {
Tessellator tessellator = Tessellator.instance;
glPushMatrix();
tessellator.setColorRGBA(ValueRed,ValueGreen,ValueBlue,ValueAlpha);
//Rest of your rendercode here
glPopMatrix();
}