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MegaSquirt 3 EMS System V3.57


Frequently purchased together


8' MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready) – optional

DB15 Pigtail Harness – optional

USB Tuning Cable for MegaSquirt-III/ MS3Pro 1st Gen – optional

SKU: MS3357-C_BL Category: Tags: , , , , , , , , Brand:


Important Note:  Due to supply chain challenges and the lack of ability to have parts anodized at this time, we are transitioning to brushed silver enclosures.  We appreciate your understanding.  

MegaSquirt 3 Engine Management System w/PCB3.57 – The MegaSquirt 3 is a drop in daughter card that greatly expands the MegaSquirt’s functionality. This model is equipped for basic, batch fire, but can be expanded to add sequential injection and 8 channel ignition control with an MS3X card (sold separately). Advantages include loads of additional processing power, speed, and features over the existing MS1 and MS2 systems. The MegaSquirt 3 daughter card alone provides these features and more:

  • VE and ignition tables are now both 16 x 16
  • 0.1% steps on VE table, 0.1 degree steps on ignition table
  • Socket for an onboard SD card – no laptop required for data logging  (SD Card not included)
  • Built in USB port
  • GM stepper IAC control
  • Closed loop idle and mixture control
  • CANBus communications for interface with GPIO Board, IO Extender, or other devices
  • Staged injection
  • Native support for many different OEM trigger patterns

Ready for two fuel outputs and one 5V logic level spark output. The MegaSquirt 3 also gives you a starting point for even more expansion. Further expansion with MS3X enables features like:

  • 8 channels sequential fuel control
  • 8 channel sequential ignition control
  • Individual fuel and spark trim for cylinder by cylinder tuning
  • 2 and 3 channel PWM IAC control
  • 2 stage nitrous controller
  • Table switching for multi-fuel engines
  • 2 step launch control

For complete MS3 documentation and more see

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What harness do I need with this?

  • You need only the MegaSquirt (MS1/MS2/MS3 Ready)  harness.

What inputs and outputs is the MS3 V3.57 set up for?

  • It is set up for basic fuel control and single channel logic level spark output, with the following inputs and outputs:
    • Coolant temperature
    • Air temperature
    • MAP sensor (built in)
    • Throttle position sensor
    • O2 sensor – narrow band or external wideband controller
    • Single RPM input – Hall, optical, or VR
    • On/off, stepper, or PWM idle control – unused idle control outputs can be repurposed as general purpose relay control outputs
    • Fuel pump relay
    • Two fuel injector banks
    • One 5 volt logic level spark output
    • CANbus

What firmware does it have?

  • The MS3 V3.57 ships with the latest MS3 code. The code it initially shipped with will be indicated on a sticker on the underside of the unit.

Is the V3.57 board available in kit form?

  • The V3.57 is essentially a V3.0 that has been changed for machine assembly with very few differences. Consequently, it is not offered in kit form.

What connections are on the DB15?

  • By default, it only has a couple extra reference voltage and ground pins for sensors. The DB15 can be used for adding optional I/O if you run out of pins on the main connector.

Where is it built?

  • The components are assembled at various locations in the US, with final assembly completed in Gainesville, Georgia.

What is the warranty?

  • We provide a one year limited warranty against manufacturing defects.

Questions & Answers

  1. 0 votes

    Yes, this is supported. You may need to adjust the VR trim pots on the MS3X to get the right amount of noise filtering for the cam signal.

  2. 0 votes

    The MS3 can run an EDIS type ignition with or without the module. If not using the module, you will have a much easier time using the MS3X; an MS3 without MS3X will need considerable modification, while adding the MS3X gives you eight spark outputs out of the box.

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