Standalone Engine Management SEM103 Based on MS3x

$USD 220.0

Out of stock

SKU: sem103 Category:


Standalone engine management system based on Megasquirt MS3x Processor and firmware with enhanced inputs and output ports. It is capable of controlling sequential injection on engines up to 4 cylinders, or semi-sequential up to 8 cylinders, combined with direct fire ignition for engines up to 4 cylinders or wasted spark ignition on engines up to 8 cylinders. Can be connected as fully standalone ECU or as piggyback and share the sensor reading with the stock ECU as it has differential trigger inputs, The 4 bar internal MAP sensor can read up to 44psi of boost, Programmable knocking detector circuit can be used to adjust the ignition timing,  5V ref voltage, and internal switch to pull up resistor. The CAN bus facilitate the communication with SPTRONICS O2 sensor wideband controller and EGT amplifier for more accurate reading. It has dedicated inputs (Crank, CAM, CLT, IAT, MAP, TPS, O2 and knocking) and 9 low side outputs to drive injectors or any solenoid valve. 4 dedicated ignition outputs. Bluetooth connectivity.


  • 2x Deferential Trigger inputs (Hall, VR and Opto).
  • 4x High impedance injectors output  2.5A each.
  • 4x Ignition output 1A max (5V or 12V)
  • 4x dedicated analog input, coolant temperature, Intake air temperature,  O2 sensor, Throttle position.
  • Fuel pump output.
  • Tachometer output (5V or 12V).
  • 2/3 wire Idler control.
  • Knocking input with adjustable gain.
  • 2x analog/digital inputs.
  • 3x 2.5A outputs.
  • 4 bar built in MAP sensor.
  • Fully compatible with MSextra Software
  • Fuel Table 16×16
  • Ignition Table 16×16
  • Connected to computer through USB.
  • Supports CAN Bus
  • Bluetooth connectivity.
  • Can be connected as standalone or piggyback
  • Dimensions  95mm x 76mm


Fuel table size 16×16
Fuel table resolution 0.1%
rpm resolution 1 rpm
Accel enrichment Simple (TPS,MAP), Enhanced (wall-wetting)
Spark table size 16×16
Advance resolution (commanded) 0.1 deg
Injector phasing Bank/batch fire,Semi sequential or 4cyl sequential
Injector timing Timed within crank pulses or timed for start, middle, end of injection pulse
Injector trim Mapped trim table per cylinder when running sequential.
Spark trim Not adjustable
Distributor spark Y
Trigger return dizzy Y
Simple wheel decoding Y
Every tooth wheel decoding Y*
Wasted spark Y
Coil on plug Y
Dual dizzy Y
Cam / 2nd tach input Y
Number of spark outputs 6
Rotary trailing Y
HEI7, GMDIS Y (with bypass control)
Oddfire wheel decoder Y
Oddfire dizzy Y
Neon/420A Y
36-1+1 Y
36-2-2-2 Y
Subaru 6/7 Y
IAW Weber-Marelli Y
Mitsubushi 6g72 Y
4/1 CAS Y
4G63 (Miata) Y
99-00 Miata Y
Renix 44-2-2 Y
Twin trigger (aka. dual spark) Y
Suzuki Swift Y
Suzuki Vitara Y (Untested!)
Daihatsu 3 cyl Y (Unproven)
Daihatsu 4cyl Y (Untested!)
Rover K Series 36-1-1 Y
Rover K Series 36-1-1-1-1 Y
Rover K Series 36-2-2 Y (Untested!)
Honda VTR1000 12-3 Y
Chrysler 2.2/2.5 Y
GM 7X native Y
Nissan 360 tooth CAS N/P>
Load methods SD, AN, map/baro (load%), ITB
Load blending Y
Load tables 2
Staged injection Y
Over-run fuel cut Y
Tachometer output Y
Launch Control/flat shift Y
Spark cut rev limit Y
Dwell duty% Y
Dwell battery correction table of %ages
Cranking pulsewidth table of %ages
Alternate cranking injection Y
Specific cranking advance, dwell Y
Fixed timing for setup Y
Test mode Pump, Inj, Coils, Idle
Closed loop idle control Y
Boost control Y (open or closed loop with PID control)
Nitrous control Y (2 stage)
Knock sensor (software) Y
Realtime barometric correction Y
Water Injection N
Table Switching Y
Configurable outputs Y
AFR target tables Y
Dual fuel tables (per bank) Y
Synchronous sensor sampling Y
Built in tooth/trigger loggers Y (tooth, trigger, composite, sync-errror)


Download Tunerstudio

Download USB driver

SEM103_rev1 Manual

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