Microsquirt Hardware Manual Megasquirt-2 Product Range MS2/Extra 3.3.x Dated: 2015-03-14 Hardware manual covering specific wiring and configuration of your Microsquirt ECU. This version of the documentation applies to: • MicroSquirt V3 as shown above running firmware MS2/Extra 3.3.x Does not apply to other Megasquirt products or other firmware versions. (c) 2014 James Murray Microsquirt Hardware Guide Table of Chapters 1 Introduction..............................................................................................................................7 2 Microsquirt System Hardware.................................................................................................9 3 Wiring.....................................................................................................................................11 4 Fuel System...........................................................................................................................36 5 Ignition System - fundamentals.............................................................................................45 6 Ignition system - specific operating modes...........................................................................74 7 Throttles...............................................................................................................................136 8 Optional Hardware..............................................................................................................137 9 Example wiring....................................................................................................................139 10 Further information............................................................................................................140 11 Appendix A Schematics.....................................................................................................140 12 Appendix B: Junkyard guide to finding EDIS....................................................................149 13 Revision history.................................................................................................................154 (c) 2014 James Murray 2015-03-14 Page 2/154 Microsquirt Hardware Guide Contents 1 Introduction..............................................................................................................................7 1.1 Emissions and disclaimer................................................................................................7 1.2 Required tools..................................................................................................................7 1.3 How to use this manual....................................................................................................7 2 Microsquirt System Hardware.................................................................................................9 2.1 Overview..........................................................................................................................9 2.2 Microsquirt Installation.....................................................................................................9 2.3 Wiring Harness and fuses..............................................................................................10 2.4 Crank / Cam Inputs........................................................................................................10 2.5 Sensor Inputs.................................................................................................................10 2.6 Outputs...........................................................................................................................10 2.7 Tuning interface..............................................................................................................10 3 Wiring.....................................................................................................................................11 3.1 Best Practices.................................................................................................................11 3.1.1 Wire and connector choice.....................................................................................11 3.1.2 Soldering or crimping..............................................................................................11 3.1.3 Re-pinning AMPSEAL.............................................................................................11 3.1.4 Fusing......................................................................................................................11 3.1.5 Making the harness.................................................................................................11 3.1.6 Four-pin relay pin-out note......................................................................................11 3.1.7 Relay and accessory power routing.......................................................................12 3.2 Grounding (Earthing) Schemes.....................................................................................12 3.3 Core Wiring Diagram......................................................................................................14 3.4 Relay Board...................................................................................................................17 3.5 Inputs..............................................................................................................................17 3.5.1 Crank and Cam Tach inputs...................................................................................17 3.5.2 MAP (Manifold Absolute Pressure) sensor.............................................................17 3.5.3 IAT/MAT (Intake/Manifold Air Temperature) sensor................................................18 3.5.4 CLT (Coolant Temperature) sensor........................................................................21 3.5.5 TPS (Throttle Position Sensor)...............................................................................21 3.5.6 O2 (Oxygen) Sensor / Lambda Sensor..................................................................22 3.5.7 MAF (Mass Air Flow) Sensor..................................................................................24 3.5.8 Flex / Switch input...................................................................................................27 3.5.9 Spare ADC / Switch input.......................................................................................28 3.5.10 BOOTLOAD input.................................................................................................28 3.5.11 CAN comms..........................................................................................................29 3.5.12 Knock sensor........................................................................................................29 3.6 Outputs...........................................................................................................................30 3.6.1 Fuel Injector outputs...............................................................................................30 3.6.2 Ignition outputs.......................................................................................................31 3.6.3 Fuel pump output....................................................................................................31 3.6.4 Idle valve.................................................................................................................31 3.6.5 Tacho output...........................................................................................................32 3.6.6 WLED/ALED outputs..............................................................................................32 (c) 2014 James Murray 2015-03-14 Page 3/154 Microsquirt Hardware Guide 3.7 Inputs and Outputs Summary........................................................................................33 3.7.1 Pin vs. feature table................................................................................................34 3.8 Bench test wiring............................................................................................................34 3.8.1 Minimal connection.................................................................................................35 3.8.2 JimStim connection.................................................................................................35 4 Fuel System...........................................................................................................................36 4.1 Introduction....................................................................................................................36 4.1.1 Existing EFI Vehicle................................................................................................37 4.1.2 Retro-fit EFI Vehicle................................................................................................37 4.2 Single Fuel pump...........................................................................................................37 4.3 Low pressure / high pressure - twin pump.....................................................................37 4.4 Wiring the Fuel Pump.....................................................................................................38 4.5 Fuel Line.........................................................................................................................38 4.6 Fuel filter.........................................................................................................................39