Most of your commented codes are wrong. Please remove them. There's no point in keeping them. If you power the accelerometer with 3.3V, did you use 3.3V as analog reference voltage? No, according to your setup(). So your base value is not near 500 but near 338. That is the first thing I noticed. If you set the accelerometer flat, what do you get for x and y? 338 or near 500?
What do you to accomplish? You said nothing about it. From what I know, you can only sustain acceleration with circular motion. So your acceleration goes above alarm only for a short moment before you need to decelerate.