As long as you keep the app running in the background, all the data shall be saved automatically.
When you say it doesn’t show records, can you send some screenshot? Is it the timeline or the dashboard that you are talking about?
If you keep the app running in the background and sees the 3 LED ontop of the in-car receiver is solid white, it means the phone has a solid connection with the device. When low tire pressure is detected in one of your tires, you will receive push notifications on your phone and you could obviously see the corresponding Green LED flashing along with a warning buzzer beeping, you won’t miss it.
Same here, as long as the app is still running, either in the foreground or in the background, and the White LED indicator is solid on, you will receive notification when such tire conditions are detected.