Megasquirt MS3 ECU
Fully assembled and tested Megasquirt MS3 ECU. Standalone engine management controller supporting up to 8 cylinders. Sequential injection, individual coil-on-plug (COP) ignition, built-in CAN bus, wideband sensor input, VVT control, boost control and much more. Tuning via TunerStudio over USB.
Specifications
| Processor | Freescale MC9S12XEP100, 50 MHz |
| Injection | Sequential, semi-sequential, batch |
| Ignition | COP (coil-on-plug), Wasted Spark, distributor |
| Injection channels | Up to 8 (sequential) |
| Ignition channels | Up to 8 (COP) or 4 (Wasted Spark) |
| CAN bus | Built-in, 500 kbps, Simplified Dash Broadcasting |
| Wideband sensor | Built-in wideband input (0–5V) |
| Analog inputs | MAP, TPS, CLT, IAT, O2, EGT, Battery + spare |
| Outputs | PWM, Boost control, Idle valve, VVT, Tacho, Fuel pump |
| VVT | Variable valve timing control (1–2 channels) |
| Boost control | Closed-loop, Open-loop, gear-based |
| Datalog | SD card or via TunerStudio |
| Tuning | TunerStudio over Bluetooth or USB |
| Bluetooth | Built-in module, wireless tuning via TunerStudio |
| Connector | 81-pin Ampseal + DB9 RS-232 |
| Power supply | 9–22V (vehicle power) |
Description
Megasquirt MS3 is a standalone engine control unit with an open architecture, designed for tuning and replacing factory ECUs. Suitable for naturally aspirated and turbocharged engines with 1 to 8 cylinders. Supports various injection modes: batch, semi-sequential, and full sequential. Built-in CAN bus allows connecting external dashboards, sensors, and other devices. Wideband input allows using a wideband O2 sensor without an additional controller. Tuning and calibration is done through TunerStudio software over USB. Datalogging is available for engine analysis.
Wiring Diagrams
Sensor connections
Injectors & ignition
Power circuits & relays
Full pinout (81 pins)