jQuery: JSON.parse doesn't work for a long JSON string

I am downloading a large text file from a server to a phonegap app. The text is valid JSON in string form. I write the text data to the device's file system, then read it later. I fetch the text data using the filereader adn this seems to work fine. Its when I parse the string JSON that the problem occurs.

When I download a text file containing 2500 elements(records returned from a DB and returned in json format) the JSON.parse(stringJSON) function works fine and returns a JSON object, however if I increase the number of elements returned from the server to 3000 then I get no response, teh json output seems to be formatted correctly. It looks like a memory problem, the JSON data is at most 1.5MB, is that too much to parse using jquery's JSON.parse, with phonegap. I looked at this page and tried including parse_json instead of JSON.parse and it still returns nothing (I included the relevant script in my page).

var ft = new FileTransfer();

 ft.onprogress = function(progressEvent) {
    if (progressEvent.lengthComputable) {
        var perc = Math.abs(Math.floor((progressEvent.loaded / progressEvent.total) * 100));
        $loading.html(perc + " Loading...")
    } else {
        if($loading.innerHTML == "") {
            $loading.innerHTML = "Loading";
        } else {
            $loading.innerHTML += ".";
        }
    }
};

var dlPath = DATADIR_separate.fullPath + "/"+foldername_separate+".html";
ft.download("http://downloadURL", dlPath, function(){
    alert('saved');
    $loading.hide();
    remove_permanent_overlay();
}, function(){
    alert('fail');
    $loading.hide();
    remove_permanent_overlay();
});

then after all the file reader callbacks:

function readAsText_READ(file) {
var reader = new FileReader();

reader.onloadend = function(evt) {
    alert('loaded');//this fires, so filereader is working
    //alert(evt.target.result);//this alerts even with a large string
    //var parseTarget = JSON.parse(evt.target.result);//works for smaller strings fails with larger strings
    console.log('parsing now...');
    var parseTarget = json_parse(evt.target.result);//same result as JSON.parse
    console.log(parseTarget);
    //var parseTarget = $.parseJSON( evt.target.result );
    //var parseTarget = eval( "("+evt.target.result+")" );
    //alert(parseTarget);
    alert(parseTarget["879"]);
};

reader.readAsText(file);
//reader.readAsDataURL(file)
alert('reading file: '+file);

}

*Edit In phonegap's weinre debugger I get the following when I try to read the large json string.

parsing...
processMessage failed: Message: S01 File1238321490
s{"really long json... jsonetc..."}
processMessage failed: Error: [object Object]
processMessage failed: Stack: undefined

not quite sure what those error messages mean, I'll try find out...

Any help would be greatly appreciated.