Autocomplete search with One letter is not working

When I search the user name in the search box of autocomplete by using the first letter of the user name. Its not showing any names. When I enter the second letter its showing the names. But when I erase the second letter of the name and its showing the names with the single letter.

Here are the code I'm using:

keyUp: function (e) {
                var inputFieldName = this.name;
                var inputFieldValue = this.value;
                console.log(inputFieldName);
                console.log(inputFieldValue);
                var autocompletedata='';
                if(inputFieldValue != undefined){
                if(inputFieldName==='checkedoutuser' && inputFieldValue.length >= 1) {
                    var inputFieldValue = this.value;
                    Vsuite.services({
                           service:'searchsuggestion',
                          async: false,
                           type: 'get',
                           json: true,
                           data: {
                                  facetValue: inputFieldValue, 
                                  resultSetLimit: 20
                         }
                          }).done(function (responseData) {
                              console.log(responseData);

                              var checkedOutId = $('.repeat-instance input[name="'+inputFieldName+'"]').attr('id');
                              this.setProperties({
                                  autocompletedata: responseData,
                            });
                              console.log(autocompletedata);
                              console.log(responseData);
                               $('#'+checkedOutId).autocomplete({
                                    source: responseData,
                                    delay: 1000,
                                    minLength: 1,
                                    open: function () {
                                        console.log($('#autocomplete-add-refine').length)
                                        console.log(checkoutUserList.length)
                                        if ($('#autocomplete-add-refine').length == 0 && checkoutUserList.length >= 5) {
                                                $('<li id="autocomplete-add-refine"><b>Continue typing to refine further</b> </li>').appendTo('ul.ui-autocomplete');
                                                console.log($('#autocomplete-add-refine').length);
                                                $('ul.ui-autocomplete').css({
                                                    'max-height': '120px',
                                                    'overflow-y': 'auto',
                                                    'overflow-x': 'hidden'
                                                });
                                        }
                                        else {
                                            $('#autocomplete-add-refine').remove();
                                        }
                                   }
                              if($('#autocomplete-add-refine').length > 0 && checkoutUserList.length <=20) {
                                $('#autocomplete-add-refine').remove();
                            }

                               });
                          }.bind(this));
                }
                else {
                    Ember.run.later(this, function () {
                        this.$().change();
                    }, 125);
                }
                }
            },

I need the search names needs to come when I enter the single letter of the name on the first time itself. Your help will be appreciate. I'm using Ember 1.4.0.