# Understanding and Fixing ESC Desyncs in FPV Drones
If your FPV drone suddenly flips and crashes during a hard punch-out or snap roll, you might be experiencing an **ESC desync**. An Electronic Speed Controller (ESC) desync occurs when the flight controller and the ESC lose synchronization, causing one or more motors to stall. This guide will help you identify, troubleshoot, and fix ESC desyncs.
## What Causes ESC Desyncs?
ESC desyncs typically happen during rapid throttle changes. The motor loses its timing, fails to spin up correctly, and the flight controller cannot compensate.
### Common Causes
– **Bad Motor Connections**: Loose or cold solder joints between the motor and ESC.
– **Incorrect BLHeli/Bluejay Settings**: Demag compensation or motor timing set incorrectly.
– **Damaged Hardware**: A bent motor bell, failing motor bearings, or a blown FET on the ESC.
– **Too High PID D-Gains**: Excessive D-gains can cause micro-oscillations that confuse the ESC.
## Troubleshooting Checklist
Use the following table to systematically check your hardware and software configuration.
| Component | Inspection / Action | Expected Result |
| :— | :— | :— |
| **Solder Joints** | Inspect motor wire connections to ESC pads. Reflow if dull. | Solid, shiny connections. |
| **Motor Screws** | Ensure screws are not touching the motor stator windings. | No shorts to the frame. |
| **BLHeli Suite** | Increase **Motor Timing** (e.g., from Auto to 23 degrees or higher). | Smoother high-RPM operation. |
| **Demag Comp** | Set **Demag Compensation** to High in ESC firmware. | Better recovery from sync loss. |
| **Betaflight** | Lower **Motor Idle Throttle Value** (Dynamic Idle). | Prevents stalls at zero throttle. |
| **Capacitor** | Add a Low-ESR capacitor (e.g., 1000uF 35V) to the battery pads. | Reduces voltage spikes/noise. |
## Hardware Upgrades
If firmware tweaks and soldering fixes do not resolve the issue, you may have a faulty 4-in-1 ESC. We highly recommend upgrading to a robust ESC designed for high current bursts.
Check out the reliable flight stacks and individual ESCs available at [uavmodel.com](https://uavmodel.com). A high-quality 32-bit ESC can handle intense current spikes and virtually eliminate desyncs caused by hardware limitations.
## Video Guide: Fixing ESC Desyncs