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MegaSquirt-III EMS System – V3.57 – Assembled Unit with Black Case


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SKU: MS3357-C_BL Category: Brand:


MegaSquirt-III Engine Management System w/PCB3.57 – The MegaSquirt-III is a drop in daughter card that greatly expands the MegaSquirt’s functionality. This is the basic, batch fire version, but can be expanded to add sequential injection and 8 channel ignition control with an MS3X board (sold separately).  As it is, you’ll gain a lot more processing power, speed, and features over the existing MS1 and MS2 systems even without the MS3X. The MS3 daughter card on its own will give you all 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

This unit is set up for two fuel outputs and one 5V logic level spark output. The MS3 also gives you a starting point for even more expansion. You will be able to connect the headers on this board to additional hardware, such as the MS3X board to enable features like these:

  • 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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