Manuals for MegaSquirt MS1/Extra, MS2/Extra and MS3 firmwares on Megasquirt-1, Megasquirt-2, Microsquirt, Microsquirt-module (DIY-PNP) and Megasquirt-3

If you live or intend to operate your engine in an area that has specific pollution regulations, but sure to check the laws that apply in your locality to determine if using a MegaSquirt® or MicroSquirt® controller is legal for your application.

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Jump to: Megasquirt-1 - - Megasquirt-2 / Microsquirt / Microsquirt-Module - - Megasquirt-3 - - MS3-Pro - - (Spectre) EMS-Pro - -
Tuning Software - - Trans control - - Schematics - - Stim

Megasquirt product information

DIY Assembly
  • Assembly
  • Downloads
  • MS1/Extra manuals

    Configuration and setup for Megasquirt-1


  • MS1 Extra Info, Downloads

  • MS1 Extra Basic Configuration Manual
  • MS1 Extra Software Manual
  • Advanced Settings (Hybrid Alpha-N and MAF)
  • 300 and 400KPa Sensors
  • Map Sensor Settings
  • Idle Control valves
  • Layout of the Settings Pages in Megatune
  • MegaView
  • Fuel Only Setup, No Ignition
  • Ignition Selection
  • Spark Settings
  • This / Next Cylinder
  • Idle Advance Settings
  • Knock Settings
  • IAT/CLT_Related Ignition
  • Dwell Settings
  • Stim for Wheel
  • Rotary Trailing Ignition
  • Odd Fire Wheel Settings
  • MS1 Tuning Manual
  • Ignition Setup Options
  • Trigger Input Options for V2.2 PCBs (green pcb):
  • Trigger Input Options for V3.0 PCBs (blue pcb):
  • Spark Output Options for V2.2 PCB (green pcb):
  • Spark Output Options for V3.0 PCB (blue pcb):
  • MS1-Extra Quick Guide to Tuning / Datalogging and using MegaTune
  • Hardware
  • MS1 Extra Hardware Manual
  • Knock Detection
  • Mass Air Flow Meters
  • Nitrous (N2O) Control
  • Second O2 Sensor
  • Dual Table
  • EGT Logging
  • Boost Control
  • Anti-rev / traction control

  • Technical
  • MS2/Extra manuals
    Megasquirt 2 manuals
    Microsquirt manuals
    Microsquirt-module manuals



    microsquirt module

    Configuration and setup for Megasquirt-2, Microsquirt, Microsquirt module, DIY-PNP, MSPNP2

    Downloads page for firmware   -  Donate

    As of July 2014, the web-manuals have been superceded by manuals in PDF format.

    Megasquirt-2 Setting Up manual

    MS2/V3.0 Hardware manual

    MS2/V3.57 Hardware manual

    Microsquirt Hardware manual

    Microsquirt-Module Developers guide

    Megasquirt-2 TunerStudio Reference manual

    For the old web-manuals, Click here

    Megasquirt 3 manuals

    Megasquirt 3 (aka MS3, MS3EFI) is the latest Megasquirt product offering up to 8cyl sequential fuel and spark.


    These manuals are presently (mid 2014) under-going a re-write to PDF format. Please check back soon for updates.

    DRAFT Megasquirt-3 Setting Up manual

    DRAFT MS3base/V3.0 Hardware manual

    DRAFT MS3X/V3.0 Hardware manual

    DRAFT MS3base/V3.57 Hardware manual

    DRAFT MS3X/V3.57 Hardware manual

  • Initial setup
  • Hardware, Sensors and wiring
  • Configuration
  • Background information
  • MS3-Pro

    ms3 pro

    MS3-Pro manuals are available on DIYAutoTune.com's site.

    Spectre EMS-Pro

    Manuals for your product: Install Guide   Tuning Guide   Megatune Reference

    General Megasquirt-1 manuals here

    Tuning software

    Most users will want to install Java, TunerStudio and MegaLogViewer

    Transmission controller

    Alternative firmware that converts your Megasquirt into an automatic transmission controller

  • Introduction
  • Schematics

    For assembly, diagnostics and repair.

  • Board Schematics
  • Megasquirt Simulator


  • JimStim information
  • Megastim v1 information
  • Megastim v2.1 information
  • Tutorial on bench testing with the Stim (in progress)
  • Megamanual

    The previous Megasquirt manuals.

  • Megamanual index
    Caution!! The MegaManual should not be used for MS1/Extra, MS2/Extra or MS3 as the settings and wiring are frequently different. You will only confuse yourself.
    MS1/extra headerMS1/Extra firmware - use this MSEXTRA manual
    MS2/extra headerMS2/Extra firmware - use this MSEXTRA manual
    MS3 headerMS3 firmware - use this MSEXTRA manual
    94% of users run MSEXTRA firmware and should use this MSEXTRA manual ONLY.

    Users of basic fuel-only MS1 firmware and the alternative MS2 B&G firmware will find instructions in the Megamanual.
    b+g headerMS2 B&G firmware - use MegaManual
    The MSGPIO board is covered in the MegaManual

  • MegaSquirt® and MicroSquirt® controllers are not for sale or use on pollution controlled vehicles. Check the laws that apply in your locality to determine if using a MegaSquirt® or MicroSquirt® controller is legal for your application.
    ©2004, 2009 Bruce Bowling and Al Grippo. All rights reserved. MegaSquirt® and MicroSquirt® are registered trademarks.