How to overcome failures while doing UI Automatin for Knockout Web sites

I'm working on knockout based site using selenium web driver + c# to automate. my test methods fail because of elements not found / not able to click as the site is slow / or the binding/ rendering of html is slow after the ajax calls are finished.

below is sample code i used to know the ajax calls have finished and i can proceed to search elements.

public static void waitForAjax(IWebDriver driver, String action)
        {
            try
            {
                TimeSpan tp = TimeSpan.FromSeconds(1000);
                driver.Manage().Timeouts().SetScriptTimeout(tp);
                ((IJavaScriptExecutor)driver).ExecuteAsyncScript(
                "var callback = arguments[arguments.length - 1];" +
                "var xhr = new XMLHttpRequest();" +
                "xhr.open('GET', '/" + action + "', true);" +
                "xhr.onreadystatechange = function() {" +
                "  if (xhr.readyState == 4 && xhr.status == 200) {" +
                "    callback(xhr.responseText);" +
                "  }" +
                "};" +
                "xhr.send();");
            }
            catch
            {
            }
        }

Im calling the above method before going to find the elements

Test Method

try
            {
                IWebDriver _Driver;
                IWebElement ele;
                FirefoxDriverService _Service = FirefoxDriverService.CreateDefaultService(@"D:\CodePlex_C#\SeleniumTestWithHtml\SeleniumTestWithHtml\Drivers");
                _Driver = new FirefoxDriver(_Service);
                _Driver.Navigate().GoToUrl("HomepageURl");
                System.Threading.Thread.Sleep(2000);
                waitForAjax(_Driver,"Call1");
                waitForAjax(_Driver,"Call2");
                System.Threading.Thread.Sleep(2000);
                ele = _Driver.FindElement(By.LinkText("DASHBOARD"));
                ele.Click();
                //System.Threading.Thread.Sleep(2000);
        waitForAjax(_Driver,"Call1");
                waitForAjax(_Driver,"Call2");
                waitForAjax(_Driver,"Call3");
                waitForAjax(_Driver,"Call4");
                System.Threading.Thread.Sleep(2500);
                ele = _Driver.FindElement(By.Id("QuickSearchCnt"));
                ele.Click();
            }

But My Code Fails. I suspect the code to find the calls have finished to execute is not working properly.

I Need help in knowing is my approach right? and need help in fixing the issue.