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MegaSquirt 3 ECU with MS3X Expansion

MegaSquirt 3 EMS System V3.57



Frequently purchased together

Product Quantity

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

DB15 Pigtail Harness

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

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

    Hi folks. Do you have a handle on the odd Subaru 6/7 crank trigger or would I have to switch it out for the WRX unit? I'm planning to run this on a 93 Subaru 2.2L turbo car. I bought a Micro squirt awhile back, but couldn't find any long term success stories. Got a lot of negative feed back from my Suby crowd, so I sent it back to you. I'd be will to try the MS 3, if it will work for me with out too much headache. Thanks. Steve.
  1. 0 votes
    Q Hi folks. Do you have a handle on the odd Subaru 6/7 crank trigger or would I have to switch it o...... Read more
    Asked by Steve Webster
  2. Is the MS3 compatible with a ford EDIS system and do i need the module to run it?
  3. 0 votes
    Q Is the MS3 compatible with a ford EDIS system and do i need the module to run it?
    Asked by Hugh
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