This is telling you a lot about the problem "when i disable the accelerometer block the app work properly." There is something wrong in where you place that block in the event handler or something wrong with how you schedule a sequence of events. If you would post the blocks where you disable the accelerometer, you would get specific advice.
App Inventor apps are event driven, which simply means one activity can only start after a previous activity has finished. Therefore this could be a timing issue as a guess or simply an issue of how much you process.
Are you using AI to control LegoMindstorms or an Arduino or what? If you use the Search for topics block at the top of this page to the right of the colorful Google and input the search words, you can benefit by previous Forum discussions if you peruse the list of provided links. How to do what you want might be discussed there.
Regards,
Steve