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MegaSquirt MS3 Hardware Manual

Megasquirt-3 series
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MS3(base)/V3.0 Hardware Guide
Megasquirt-3 Product Range
MS3 1.4.x
Dated: 2016-11-13
Hardware manual covering specific wiring and configuration of your Megaquirt MS3/V30 ECU.
This version of the documentation applies to:
MS3 on a V3.0 mainboard without MS3X as shown above running firmware MS3 1.4.x
•
See the Setting Up manual for more detail on version numbers.
Does not apply to other Megasquirt products or other firmware versions.
(c) 2014-6 James Murray

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Summary of Contents for MegaSquirt MS3

  • Page 1 Hardware manual covering specific wiring and configuration of your Megaquirt MS3/V30 ECU. This version of the documentation applies to: MS3 on a V3.0 mainboard without MS3X as shown above running firmware MS3 1.4.x • See the Setting Up manual for more detail on version numbers.

  • Page 2: Table Of Contents

    MS3base/V3.0 Hardware Guide Table of Chapters 1: Introduction..........................8 2: Megasquirt System Hardware....................10 3: Wiring...........................12 4: Fuel System..........................60 5: Ignition System - fundamentals....................70 6: Ignition system - specific operating modes................110 7: Throttles..........................183 8: Optional Hardware......................184 9: Example wiring........................184 10: Further information......................186 11: Appendix A Schematics....................186...
  • Page 3 1: Introduction..........................8 1.1 Emissions and disclaimer....................8 1.2 Required tools........................8 1.3 How to use this manual....................8 1.4 Scope of advice without MS3X..................9 2: Megasquirt System Hardware....................10 2.1 Overview........................10 2.2 Megasquirt Installation....................10 2.3 Wiring Harness.......................11 2.4 Crank / Cam Inputs......................11 2.5 Sensor Inputs.........................11 2.6 Outputs...........................11...
  • Page 4 MS3base/V3.0 Hardware Guide 3.5.1 Fuel Injector outputs....................42 3.5.2 Ignition outputs.......................42 3.5.3 Fuel pump output....................42 3.5.4 Idle valve.........................43 3.5.5 Tacho output......................47 3.5.6 Other relay outputs....................48 3.5.7 Boost control output....................48 3.5.8 Alternator control wiring..................49 3.6 Bench test wiring......................58 3.6.1 Minimal connection....................59 3.6.2 JimStim connection....................59 4: Fuel System..........................60 4.1 Introduction........................60 4.1.1 Existing EFI Vehicle....................61...
  • Page 5 MS3base/V3.0 Hardware Guide 5.3.2 Logic coils.......................92 5.3.3 Amplifiers (ignitor, power transistor, ignition module)...........100 5.3.4 High current coils....................105 5.3.5 CDI modules (e.g. MSD, Crane etc.)..............106 5.3.6 Mazda Rotary ignition wiring................107 5.3.7 Toyota DLI ignition wiring..................108 6: Ignition system - specific operating modes................110 6.1 Coil negative for fuel only.....................112 6.2 Distributor pickup......................113 6.2.1 Traditional vac/mech distributor................113...
  • Page 6 MS3base/V3.0 Hardware Guide 6.15 6G72...........................164 6.16 IAW Weber.........................165 6.17 Mitsubishi CAS 4/1.....................166 6.18 Mitsubishi 4G63 (and Miata)..................166 6.19 Twin trigger.........................168 6.20 Chrysler 2.2/2.5......................169 6.21 Renix 44-2-2 (66-2-2-2).....................169 6.22 Suzuki Swift........................169 6.23 Suzuki Vitara 2.0......................170 6.24 Daihatsu 3cyl......................170 6.25 Daihatsu 4cyl......................170 6.26 VTR1000........................170 6.27 Rover#1........................171 6.28 Rover#2........................171...
  • Page 7 MS3base/V3.0 Hardware Guide 12: Appendix B: junkyard guide to finding EDIS..............198 12.1 North America - EDIS4....................198 12.2 Europe - EDIS4......................199 12.3 Europe - EDIS6......................201 12.4 Europe - EDIS8......................201 12.5 Europe - 36-1 trigger disc..................201 12.6 Europe - VR sensor....................202 12.7 World - Coilpack(s).....................202 13: Appendix C: V3.0 Board Assembly..................203 13.1 Introduction........................203 13.2 Build choices......................203...

  • Page 8: 1: Introduction

    MS3base/V3.0 Hardware Guide 1: Introduction The MS3/V3.0 is an ECU based on Megasquirt-3 technology, consisting internally of an MS3 card installed on a through-hole DIY V3.0 mainboard. This manual covers MS3/V3.0 specific installation details and should be used in conjunction with the general Setting up and TunerStudio reference manuals.

  • Page 9: Scope Of Advice Without Ms3X

    This manual is written for the MS3/V3.0 without the MS3X board. Instructions for DIY modifications for inputs and outputs are given using the mainboard connections only – not the “MS3X” pin headers on the MS3 card. Customers requiring additional inputs and outputs with less internal DIY modifications are recommended to consider upgrading with the MS3X card.

  • Page 10: 2: Megasquirt System Hardware

    2.2 Megasquirt Installation The Megasquirt is not designed to be installed in the engine compartment. Typically it will be installed under the dash in a car or under the seat on a bike - but away from direct engine temperatures. The temperature must not exceed 185°F (85°C.) It should be protected from water.

  • Page 11: Wiring Harness

    MS3base/V3.0 Hardware Guide 2.3 Wiring Harness The Megasquirt can be supplied with a "pigtail" wiring harness to form the basis of your own wiring. 2.4 Crank / Cam Inputs The Crank and Cam sensors provide the Megasquirt with engine position information which is critical for ignition timing.

  • Page 12: 3: Wiring

    MS3base/V3.0 Hardware Guide 3: Wiring A main step in your Megasquirt installation is connecting up the wiring. Be sure to follow the guidance here to avoid common mistakes that will often lead to problems. 3.1 Best Practices 3.1.1 Wire and connector choice For many first-time users, it may be tempting to re-use old connectors and wiring.

  • Page 13: Grounding (Earthing) Schemes

    The Megasquirt measures the voltage from the sensor and converts it into a temperature, position etc. reading. If that sensor is grounded to anything other than the Megasquirt itself, then that input voltage will be altered by any external voltage drops. For a sensitive measurement such as AFR (lambda) this can be a real problem. All good wideband controllers offer a high-current ground (connects to engine) and a sensor/signal ground (connects to Megasquirt.)

  • Page 14: Core Wiring Diagram

    If re-using or splicing into OEM wiring, do not assume that their wiring is OK. Always follow the above principles. As a check, with the Megasquirt connector unplugged, ensure that the sensor grounds have no continuity to engine/body ground. Your sensor readings will be junk if they do have continuity - the sensors must ground at the Megasquirt only.

  • Page 15: Optional Connections

    SPR3, SPR4 have no standard function and are spare IAC1A, IAC1B, IAC2A, IAC2B are typically connected to the stepper outputs from the MS3 card. FIDLE as standard is only suitable for switching a relay. To use it with a 2-wire PWM idle valve the transistor on the mainboard needs uprating.
  • Page 16 All pins marked # in this table are raw CPU pins and must not be directly connected to anything outside of the Megasquirt case without a protective circuit. (c) 2014-6 James Murray...
  • Page 17 MS3base/V3.0 Hardware Guide (c) 2014-6 James Murray 2016-11-13 Page 17/222...
  • Page 18 MS3base/V3.0 Hardware Guide Main plug (DIYAutoTune.com colors) Pin# Name Color In/Out Function Max amps Black Crank sensor ground Crank sensor shield SPR1 (Comms) (CANH) SPR2 Tan/Red (Comms) (CANL) SPR3 Tan/Green spare SPR4 Tan/Orange spare Black/White Sensor ground spare GND spare GND spare GND spare GND spare GND...

  • Page 19: Relay Board

    The 'Relay Board' is an optional add-on that may be useful for installs that do not have any existing EFI wiring. It provides a 'main' relay to switch clean power to the Megasquirt, a 'fuel pump' relay to operate the pump and accessories and a 'fast idle' relay for an on/off type idle valve.
  • Page 20 (Out) (High current ignition) FP (Pump) Via fuel pump relay Relay Outputs The FIDLE and FP ground outputs from the Megasquirt are used to control relays on the relay board. Relay Board # Relay Board Name In/Out Function Max amps...

  • Page 21: Inputs

    3.4 Inputs 3.4.1 Crank and Cam Tach inputs These sensors provide the Megasquirt with engine position information and are used to schedule fuel and spark. See Crank and Cam tach inputs for detailed information on these sensors and wiring. 3.4.2 MAP (Manifold Absolute Pressure) sensor The MS3/V3.0 uses an internal MAP sensor.
  • Page 22 MS3base/V3.0 Hardware Guide MAP sensor hose connects here This sensor measures air pressure on absolute scale where zero is a complete vacuum and sea-level ambient pressure is around 101kPa. This sensor is the primary input for the "Speed-Density" fuel algorithm. Alpha-N users do not require a MAP sensor and can optionally use the built-in sensor as a baro sensor.

  • Page 23: Iat/Mat (Intake/Manifold Air Temperature) Sensor

    MS3base/V3.0 Hardware Guide 3.4.3 IAT/MAT (Intake/Manifold Air Temperature) sensor This external sensor measures the temperature of the air entering the engine. This is used to calculate air density and is a key factor in the Speed-Density fuel calculation. The temperature sensor is a variable resistor (a thermistor). Higher temperatures give a lower resistance, the response is non-linear.
  • Page 24 MS3base/V3.0 Hardware Guide Temperature sensor resistance 120000 100000 80000 60000 40000 20000 Temperature (degF) The red dots are the three standard calibration points for GM sensors. The ECU uses a circuit to convert the resistance into a voltage that it measures. Temperature sensor signal at ECU Temperature (degF) 3.4.3.1 Sensor calibration...
  • Page 25 MS3base/V3.0 Hardware Guide The manual calibration process requires the use of a multimeter set to measure resistance and ideally a thermometer. Without a thermometer your calibration will be fairly close but not perfect. 1. Set the meter to ohms and connect the meter to the two terminals on the MAT or CLT sensor. 2.

  • Page 26: Clt (Coolant Temperature) Sensor

    This external sensor measures the position of the throttle plate. It is a variable resistor (potentiometer) and sends a 0-5V signal back to the Megasquirt. The sensor has three wires, 5V supply (TPSVREF), Ground (sensor ground return) and signal. The Megasquirt converts the signal to a 0-100% scale using your calibration numbers.

  • Page 27: O2 (Oxygen) Sensor / Lambda Sensor

    MS3base/V3.0 Hardware Guide Any install not using a TPS should connect the TPS input to sensor ground to prevent the reading "floating". 3.4.6 O2 (Oxygen) Sensor / Lambda Sensor 1-wire Narrowband 4-wire Narrowband Wideband The O2 / oxygen sensor / lambda sensor input gives feedback on the air:fuel ratio (mixture) of the engine and is screwed into a threaded bung which is welded into the exhaust system.
  • Page 28 Wideband sensors require an external controller for use with the Megasquirt. Widebands are more expensive than narrowband sensors but give readings over a far wider range of exhaust mixtures. When used with a Megasquirt they give you the ability to tune your engine in the rich (power) and lean (cruise) regions. Strongly recommended.

  • Page 29: Maf (Mass Air Flow) Sensor

    MS3 supports voltage MAFs (most common) and frequency MAFs (such as LS1). 3.4.7.1 Voltage MAF The sensors have at least three wires, 12V supply, Ground (sensor ground return) and signal to the Megasquirt. To connect a MAF to MS3/V3.0 internal hardware modifications are required. You may choose from either pin 'JS5 (ADC6)' or 'JS4 (ADC7)' so long as the input port setting in TunerStudio is set to match.
  • Page 30 MS3base/V3.0 Hardware Guide Voltage MAF Solder into proto area. Run jumper wire to JS5 or JS4 (your choice.) Run jumper wire to SPR3 or SPR4 (your choice.) Ford 4 pin MAF This earlier style MAF has an oval connector. A = Switched 12 Volts Supply B = Power Ground C = MAF Sensor Ground D = MAF Sensor Signal...
  • Page 31 Many GM (USA) vehicles from 1994 onwards use an AC Delco frequency MAF. (Earlier Bosch units are voltage type.) The sensors have at least three wires, 12V supply, Ground (sensor ground return) and signal to the Megasquirt. (c) 2014-6 James Murray...
  • Page 32 MS3base/V3.0 Hardware Guide To connect a MAF to MS3/V3.0 internal hardware modifications are required. Without the MS3X, pin JS10 is the only option. Set the input port setting in TunerStudio to match. Externally you choose which pin on the main connector is used. Typically SPR3 or SPR4 would be used if they are free.
  • Page 33 E = MAF Sensor Signal 3.4.7.3 MAF flow curve The flow response of MAF sensors is non-linear and uses a calibration tuning curve in the Megasquirt to convert the input signal into a grammes/second flow rate number. MAF sensor response (Ford V8)

  • Page 34: Flex / Switch Input

    The Flex fuel (or fuel composition) sensor detects the percentage of ethanol within the fuel passing through it. This can be used by the Megasquirt to automatically adjust fuel and spark to allow for the change in fuel. Higher ethanol blends require more pulsewidth and additional spark advance.

  • Page 35: Spare Analogue (Adc) Inputs

    MS3base/V3.0 Hardware Guide 3.4.9 Spare Analogue (ADC) inputs The JS4, JS5 connections on the MS3 card can be used as 0-5V analogue inputs. The Generic Sensors system should be used to translate the raw ADC value into useful temperature or pressure numbers.

  • Page 36: Switch Inputs

    This is a pressure sensor from Honeywell with a 1/8"NPT thread and a plug the same as GM TPS plugs. The sensor takes a 5V supply (from TPS REF), signal ground at the Megasquirt and gives a 0-5V output (actually 0.5 to 4.5V).

  • Page 37: B/Ld Boot Jumper

    3.4.11 B/LD boot jumper The B/LD jumper on the MS3 card is shorted (with a shunt) to force the Megasquirt into "bootloader" monitor mode. This is only typically needed when loading the firmware for the first time. It can optionally be used if the firmware has become corrupted (e.g.

  • Page 38: Can Comms

    The CANH/L wires are used to connect to add-on units such as transmission control, CANEGT interfaces, data capture or compatible dashboards. The Megasquirt includes a terminating resistor. To use the CAN connections, you need to run internal jumper wires as shown in section 13.4 JS6 ->...

  • Page 39: Knock Sensor

    The Megasquirt includes a terminating resistor internally, so no additional resistor is required at that end. 3.4.13 Knock sensor Megasquirt supports knock sensing with an external interface to the knock sensor. Do not connect a sensor directly to the Megasquirt - it will not work.

  • Page 40: Speed Sensor Inputs

    It allows per-cylinder detection and tuning to specific engine bores size. However, the add-on requires that the MS3X spark outputs are used and is not compatible with the "LED" spark outputs when the MS3 is used without. See the MS3X/V3.0 manual for more details. 3.4.14 Speed sensor inputs The speed sensors system expects to receive a 0-5V pulsed signal internally at the processor.

  • Page 41: Egt Input

    MS3base/V3.0 Hardware Guide 3.4.15 EGT input K-type thermocouple probe and bung. For multiple channels of EGT, an external solution such as the "CANEGT" add-on device is likely the best choice. For a single channel, it is possible to DIY a solution. Build the following circuit in the prototype area. Connect both EGT sensor wires out through spare pins on the main DB37 plug.

  • Page 42: Outputs

    3.5 Outputs 3.5.1 Fuel Injector outputs The Megasquirt has two injector outputs. These can supply up to 14A maximum each. Typically this allows up six injectors per channel. MS3/V3.0 supports both hi-z (14 ohm) and low-z (e.g. 2.5 ohm) injectors directly.

  • Page 43: Idle Valve

    Additionally it can be used for "closed-loop idle" to maintain a steady idle RPM under varying engine loads (lights on vs. off etc.) As standard, the MS3/V3.0 supports on/off type valves and stepper idle motors. Servo type idle valves are not currently supported.
  • Page 44 V3.0 modified FIDLE output The 12V supply for the idle valve must be a fused switched supply - ideally from the fuel pump relay. It must never be supplied power when the Megasquirt is off. (c) 2014-6 James Murray 2016-11-13...
  • Page 45 MS3base/V3.0 Hardware Guide 3.5.4.3 4-wire or 6-wire stepper idle valve 4-wire stepper idle valves are common on many GM vehicles. MS3 can control these directly. All that is required is that internal jumper wires are installed as per section 13.4...
  • Page 46 MS3base/V3.0 Hardware Guide Other manufacturers use 5- or 6-wire steppers which are uni-polar. These are usually wired as shown in the schematic below, with a center tap on each of two windings. In use, the center taps of the windings are typically wired to the 12V supply, and the two ends of each winding are alternately grounded to reverse the direction of the field provided by that winding.

  • Page 47: Tacho Output

    MS3base/V3.0 Hardware Guide 3.5.5 Tacho output A tacho output typically provides a 0-12V pulsed signal that is suitable for driving an aftermarket tachometer (rev counter.) Some older tachometers expect the high-current "spike" from the ignition coil and may not work directly with a 0- 12V signal.

  • Page 48: Other Relay Outputs

    SPR3 or Tacho From SPR4 etc. 1k 1/8W GND proto 3.5.6 Other relay outputs Other pins on the MS3 card can be reconfigured as outputs. Internal hardware modifications will be required. (S12) 1N4001 2N2222A / PN2222A SPR3 or From SPR4 etc.

  • Page 49: Alternator Control Wiring

    MS3base/V3.0 Hardware Guide may occur. This same circuit could be used to drive a small bulb such as a shift light instead of the solenoid. Boost solenoid (S12) 1N4001 TIP122 SPR3 or From SPR4 etc. 1k 1/8W Bottom of R43 3.5.8 Alternator control wiring The software settings for alternator control are covered in the TunerStudio reference manual.
  • Page 50 MS3base/V3.0 Hardware Guide Target Voltage Frequency Target Voltage Period 13.0V 250Hz 12.0V 0.5ms 13.3V 190Hz 12.8V 3.4ms 13.6V 154Hz 13.6V 6.3ms 14.4V 125Hz 14.4V 9.3ms 15.2V 82Hz 15.2V 12.2ms 16.0V 66Hz 16.0V 15.1ms (Firmware 1.4.x is programmed by frequency and has a maximum of 250Hz, firmware 1.5.x uses the time-period instead of the frequency.) If no signal is sent or a voltage of 12.0V is commanded, the alternator does not charge.
  • Page 51 MS3base/V3.0 Hardware Guide Capture Polarity: Inverted 3.5.8.2 Chrysler Alternators Most/all Chrysler/Jeep alternators use direct field control - the ECU gets direct control of the alternator "field" and is required to control it in a closed-loop manner to maintain system voltage. A switched, fused 12V supply is required and should be taken from the fuel-pump relay to ensure it is switched off when the engine is not running, around 5A is required.
  • Page 52 MS3base/V3.0 Hardware Guide 1970-2006 : isolated field, low-side wiring In this year range, both field terminals are available externally and a simple low-side driver circuit can be used. One side of the field is provided with fused, switched 12V and the other side is controller by the ECU. These alternators can optionally be wired as high-side with one side of the field externally grounded.
  • Page 53 MS3base/V3.0 Hardware Guide Control Mode: High speed feedback field control Control Output: high or mid current output of your choice to match your wiring Output Polarity: Inverted A warning lamp may be configured. or with a 0-5V output: Settings Control Mode: High speed feedback field control Control Output: 0-5V output of your choice to match your wiring Output Polarity: Normal A warning lamp may be configured.
  • Page 54 MS3base/V3.0 Hardware Guide P = Phase. Used as an engine speed output on some diesel engines. L = Lamp. Used as an input to enable the alternator and also as an output to indicate fault conditions. I/F = Ignition or Field. Ignition is a 12V feed to the alternator to enable it.
  • Page 55 MS3base/V3.0 Hardware Guide ECU control with load monitoring There are reported to be two types of this alternator that use the "I/F" pin for different purposes. With the wiring unplugged, measure the resistance between "L" and "I/F". If a high resistance (over 1000ohms) is found, the "I/F"...
  • Page 56 MS3base/V3.0 Hardware Guide As a recap: when mid-current (relay) outputs are used, the "inverted" output setting is required. • when digital 0-5V outputs are used, the "normal" output setting is required. • 3.5.8.5 Chevrolet 2-wire alternators RVC (remote voltage control) series alternators (two pin) have been used since the mid 2000s on many applications including Chevrolet/Daewoo vehicles.
  • Page 57 MS3base/V3.0 Hardware Guide Alternatively, a direct 0-5V output may be used. Build the circuit in section 3.4.14, in this case the circuit is used as an output, the 1k resistor protects the processor when the alternator grounds the "L" terminal. Settings Control Mode: Open-loop duty Control Output: high or mid current output of your choice to match your wiring...

  • Page 58: Bench Test Wiring

    • L = dash indicator lamp connection. • 3.6 Bench test wiring Before installing on your engine, it can be useful to install the Megasquirt on the bench to become familiar with the tuning software. (c) 2014-6 James Murray 2016-11-13...

  • Page 59: Minimal Connection

    For more extensive testing, the JimStim can be used. This has the mating DB37 connector to plug directly into your Megasquirt and can simulate many of the engine sensors. Make sure that the JimStim does not touch anything conductive as it is uninsulated.

  • Page 60: 4: Fuel System

    4.1 Introduction The fuel system install comprises electrical and plumbing work. The Megasquirt has two injector outputs. These can supply up to 14A maximum each. Up to six injectors are allowed per channel. The following shows a typical EFI fuel system.

  • Page 61: Existing Efi Vehicle

    • 4.1.1 Existing EFI Vehicle Most vehicles with EFI already fitted are readily adaptable to use Megasquirt for control. Typically all of the fuel system components will be readily suitable. However, if like many users you are increasing the power of your engine, you will need to consider whether your injectors are large enough and whether your fuel pump has adequate flow.

  • Page 62: Wiring The Fuel Pump

    Ensure it is totally leak free. 4.4 Wiring the Fuel Pump To activate the fuel pump, the Megasquirt provides a ground for the fuel pump relay circuit -see the main wiring diagram. Ordinarily, at power on, the Megasquirt will run the fuel pump for 2 seconds, then when you start cranking the fuel pump is enabled again.

  • Page 63: Fuel Filter

    MS3base/V3.0 Hardware Guide and aluminum for this purpose. Do not use plain copper and it can fatigue fail with dangerous leaks resulting. The size is generally given as the outside diameter of the tubing. Unless you have a very unusual combination (or very high horsepower, well over 500+), you should be able to use 3/8"...

  • Page 64: Injector Installation

    MS3base/V3.0 Hardware Guide 4.8 Injector installation Many "high performance" vendors offer ready made EFI intake manifolds for engines that did not originally come fitted with EFI. Or you can choose to modify your existing intake by welding, glueing or screwing in injector bungs.
  • Page 65 MS3base/V3.0 Hardware Guide Injectors Rating Required in cc/min (lbs/hr) Number of Injectors Horsepower 620 (59) 305 (29) 158 (15) 126 (12) 105 (10) 924 (88) 462 (44) 231 (22) 189 (18) 158 (15) 116 (11) 620 (59) 305 (29) 252 (24) 210 (20) 158 (15) 777 (74)

  • Page 66: Injector Impedance And Batch-Fire Wiring

    4.10.2.3 Low impedance injectors - Injector PWM Injector PWM is built into the MS3/V3.0 and allows direct connection of low-z injectors. The PWM mode is effectively "peak and hold" controlled by software. At each injection event, full power is applied to the injector until it opens, then the output drops back to a pulsed output to hold the injector open.
  • Page 67 MS3base/V3.0 Hardware Guide 30% PWM duty is recommended with MS3/V3.0. Be sure that you have sufficient power grounds from your Megasquirt to the engine. A small number of installs have reported interference from the PWMing of injectors. Re-routing the flyback current can help.
  • Page 68 Low-z injector wiring with Switched resistor Inj 1 and fused 12V supply INJ1 3R3 25W Power Megasquirt resistors INJ2 Inj 2 Switched and fused 12V supply Diagram showing one injector per channel and 3.3 ohm series resistors. (c) 2014-6 James Murray...

  • Page 69: Staged Injection

    See the TunerStudio reference manual for configuration details. 4.10.4 Sequential injection The MS3 was designed to run sequential fuel and spark. The sequential output signals are provided on the J1 and JP2 headers. These are low-voltage signals designed to feed the MS3X card.

  • Page 70: 5: Ignition System - Fundamentals

    5.2 Crank and Cam tach inputs The tach input is one of the most important signals going into the Megasquirt and correct system operation is not possible until the tach input is correctly installed and configured. Until the Megasquirt reads the correct RPM, nothing else will work.

  • Page 71: Coil Negative Input

    MS3base/V3.0 Hardware Guide The sensor types fall into a few basic families of sensors and the right way to use the sensor depends more on the type rather than the particular vehicle or manufacturer. There are also a few "special" systems in use from the eighties that combine a sensor input with an ignition driver output in one module.

  • Page 72: Vr (Magnetic) Sensor Input

    The Megasquirt has this conditioner built in. The two signal wires from the VR sensor are connected to Tach-in and GND at the Megasquirt. Ideally use a screened twisted pair cable and connect the screen to sensor ground at the Megasquirt end only.

  • Page 73: Hall Sensor Input

    MS3base/V3.0 Hardware Guide b) Solder a wire between VrOUT and TSEL c) With a small screwdriver, turn the pots, R52 and R56, about 12 turns anticlockwise (sometimes you may feel a "click" when the end position is reached, they can't be damaged by turning too far.) This sets them up for most VR sensors.
  • Page 74 MS3base/V3.0 Hardware Guide part of the engine (crank, cam sprocket etc.). As the magnet passes the hall sensor, the output switches to ground. The most common OEM arrangement for a hall sensor is within a distributor. The vanes in the distributor rotate and block or unblock a magnet.
  • Page 75 The hall sensor requires a supply voltage which is usually 12V from a fused 12V supply or 5V from the TPSREF output of the Megasquirt. The sensor is then grounded at the Megasquirt sensor ground and the signal wire connects to the Tach input. A pull-up resistor is required in the wiring harness or inside the Megasquirt.
  • Page 76 Tach in (DB37 pin 24) Ground Sensor ground at Shield Screened Megasquirt cable - if used VR Input with pullup for hall sensors, LS2/58X, optical sensors or points a) Solder a link between VRIN and TACHSELECT b) Solder a wire between VrOUT and TSEL c) Install a 1k resistor (any value 470R - 2k2 is likely OK) in the proto area.

  • Page 77: Hall Sensor Input (Built-In Pull-Up)

    MS3base/V3.0 Hardware Guide Optionally, when adjusting R56, you can measure the voltage at the "top" of R54. You'll need the board powered up. Set your meter to volts, and connect the +ve probe to the top of R54 and the -ve probe to ground. Adjust R56 to get around 2.5V on your meter.
  • Page 78 The hall sensor requires a supply voltage which is usually 12V from a fused 12V supply or 5V from the TPSREF output of the Megasquirt. The sensor is then grounded at the Megasquirt sensor ground and the signal wire connects to the Tach input.

  • Page 79: Gear-Tooth Sensor Input

    MS3base/V3.0 Hardware Guide d) Turn R56 back about 6 turns clockwise. Optionally, when adjusting R56, you can measure the voltage at the "top" of R54. You'll need the board powered up. Set your meter to volts, and connect the +ve probe to the top of R54 and the -ve probe to ground. Adjust R56 to get around 2.5V on your meter.

  • Page 80: Gm Ls 24X Crank/Cam Sensors

    MS3base/V3.0 Hardware Guide 5.2.6 GM LS 24X crank/cam sensors The sensors used on the LS family of GM engines are designed to read the crank and cam triggers specific to those engines. The 24X crank pattern uses a pair of adjacent toothed wheels and requires the specific GM sensor.

  • Page 81: Optical Sensor

    It is possible to convert a points distributor to give a tach input to Megasquirt and have control of your timing. In this case the points now only provide a tach signal and the Megasquirt is used to control the coil. Most conventional points distributors have a mechanical advance (weights) and a vacuum canister.

  • Page 82: Combined Ignition Module (Tfi, Edis, Hei, Gmdis)

    Some ignition modules, particularly from the 1980s combine the tach input and coil driving ignition output within one module. All of them supply a simple square wave digital signal to the Megasquirt and should be connected to the Tach input.
  • Page 83 MS3base/V3.0 Hardware Guide Optionally, the low-resolution inner signal alone can be used with a single coil and distributor in "Basic Trigger" mode. Optispark. When using the stock trigger disc and "Basic Trigger", the high-resolution outer track is not used. The low- resolution inner track is connected to the Tach input.

  • Page 84: 4G63 / 6G72

    MS3base/V3.0 Hardware Guide Switched 12V Sensor Sensor GND Megasquirt Outer Inner Tach in Typical settings: Spark mode = Basic Trigger Trigger angle/offset = Start at 10 deg - adjust while strobing timing. Ignition input capture = ???? Number of coils = Single coil 5.2.12 4G63 / 6G72...
  • Page 85 MS3base/V3.0 Hardware Guide the main tach input inverts the incoming signal, so the added cam tach input must do the same. The suggested circuits here respect that requirement. 5.2.14.1 Adding a cam sensor input - VR/magnetic sensor For the DIYer, the most straightforward circuit for the cam input is based on the LM1815 chip. (An alternative would replicate the crank circuit, but for the DIYer there are significantly more components.) Build the following circuit in the proto area.
  • Page 86 MS3base/V3.0 Hardware Guide h) Fit or jumper D1 and D2 5.2.14.4 Adding a cam sensor input - ground switching This option uses the spare opto-isolator on the mainboard for the cam input, with the sensor in ground-switching mode. This will usually give more reliable operation, but it does not match the polarity inversion of the VR/universal tach input - this is not a problem in "Toothed wheel"...

  • Page 87: Ignition Outputs

    MS3base/V3.0 Hardware Guide 5.3 Ignition outputs The MS3/V3.0 has provision for a single high-current ignition output as standard. Up to six ignition outputs are available with suitable internal modifications. On regular ignition installs, the ignition outputs must be connected in firing order sequence.

  • Page 88: Building Ignition Outputs

    5.3.1.2 High current output (additional) Additional BIP373 drivers can be installed inside the Megasquirt case. The simplest way is to buy a second heatsink bar and install it above the existing one. Extra BIP373 can be bolted on with the correct mica insulator.
  • Page 89 MS3base/V3.0 Hardware Guide 5.3.1.3 Logic spark outputs - FET driver method This circuit is suitable for driving LS1 type coils and many other logic coils including VW COPs with a low input impedance. See also section 5.3.1.4 for a simple method. With this wiring the Spark output must be set to "Going High".
  • Page 90 MS3base/V3.0 Hardware Guide Proto 5V or S12C 15R 1/8W Top of R26 Spark A Channels 1+2 15R 1/8W 4427 Top of R29 Spark B Proto GND Proto 5V or S12C 15R 1/8W Top of R27 Spark C Channels 3+4 15R 1/8W 4427 JS11 Spark D...
  • Page 91 MS3base/V3.0 Hardware Guide The diagram here shows the connections required for four channels (e.g. 4cyl COP or 8cyl wasted spark.) If 5th and 6th logic channels are required, build additional transistor circuits with the inputs JS5 and JS4 and route the output from the circuits to spare output pins of your choice.

  • Page 92: Logic Coils

    Spk Firing order Good engine ground 5.3.2 Logic coils These coils can directly accept the 0-5V logic level signal from the Megasquirt. The contain an ignition driver and a coil within the package. (c) 2014-6 James Murray 2016-11-13 Page 92/222...
  • Page 93 MS3base/V3.0 Hardware Guide LS1 (left), LS2 middle), Truck (right) coils A dwell figure of 3.5ms is advised for LS1 coils.(was 4.5) Note that some coils have a built-in over-dwell protection feature. If given too much dwell the coil will automatically spark. This can give a dangerous advanced spark. Be sure to strobe your timing at high revs to ensure this is not happening.
  • Page 94 MS3base/V3.0 Hardware Guide A dwell figure of 3.5ms is advised for truck coils. Note that some coils have a built-in over-dwell protection feature. If given too much dwell the coil will automatically spark. This can give a dangerous advanced spark. Be sure to strobe your timing at high revs to ensure this is not happening.
  • Page 95 MS3base/V3.0 Hardware Guide General layout for 4-cyl coil-on-plug using LS coils Switched 12V supply SENSOR Spark A spark plugs Spark B Megasquirt Spark C Customised for logic spark Spark D outputs Good engine ground Set the Spark Output to Going High. Build circuit in section 5.3.1.3...
  • Page 96 MS3base/V3.0 Hardware Guide IGN1A logic coil A - Ignition signal from Megasquirt B - Logic ground, connect to Megasquirt sensor ground C - Spark wire ground, connect to cylinder head D - Power ground, connect to battery negative E - 12 volt power (switched and fused) Set the Spark Output to Going High.
  • Page 97 This cost effective OEM logic wasted coil has a built-in ignitor. Fitted to many VAG vehicles including 1.6 litre mk4 Golfs. Intermotor 12919 To spark Switched plugs 2&3 12V supply Spark B Megasquirt Spark A Customised for logic spark outputs Good To spark engine ground plugs 1&4...
  • Page 98 4 = Spark input signal 3 5 = Spark input signal 4 6 = 12V supply Switched spark 12V supply plugs Spark D Spark C Megasquirt Spark B Customised for logic spark Spark A outputs Good engine ground (c) 2014-6 James Murray...
  • Page 99 Before using an "unknown" coil it is necessary to check the resistance to ground on the input. Using a multimeter set to resistance, check between the Spark Signal Input and Signal Ground. If you have a reading of say ~1k then the Megasquirt outputs can be used directly. (c) 2014-6 James Murray...

  • Page 100: Amplifiers (Ignitor, Power Transistor, Ignition Module)

    Bosch 0 227 100 124 Cross references Intermotor 15015. This single channel module can be used to drive a single high-current coil. Dwell is controlled by the Megasquirt. Set the Spark Output to Going High. Build circuit in section 5.3.1.3...
  • Page 101 This dual channel module can be used to drive a high-current wasted spark coil-pack for full spark control on a four-cylinder engine, or a pair of COPs on a two-cylinder engine. Dwell is controlled by the Megasquirt. Set the Spark Output to Going High. Build circuit in section 5.3.1.3...
  • Page 102 This four channel module is typically used to drive four COPs on a four-cylinder engine, it could also be used to drive a pair of high-current wasted spark coil-packs for full spark control on an eight cylinder engine. Dwell is controlled by the Megasquirt. Set the Spark Output to Going High. Build circuit in section 5.3.1.3...
  • Page 103 This aftermarket four channel module operates similarly to the Bosch 211, but is typically more cost effective. Pin-out Thickness Function Yellow 20 gauge Spark Input A (from Megasquirt) White 16 gauge Spark Output A (to coil negative) Orange 20 gauge...
  • Page 104 MS3base/V3.0 Hardware Guide Violet 16 gauge Spark Output D (to coil negative) Black 4 x 14 gauge Ground (to engine block or cylinder head) Recommended - build circuit in section 5.3.1.3. Set the Spark Output to Going High. The wiring in section 5.3.1.4 is not recommended. As an alternative, install 330R resistors in the prototype area.

  • Page 105: High Current Coils

    Shown are conventional single coil, GM wasted spark coil, Ford wasted spark coil-pack, Renault 2-wire COP. All of these coils are high current coils and require an ignition amplifier module (ignitor) to connect to the Megasquirt. 3-wire COPs are ambiguous, many are high-current (needing an ignitor), some may be logic level with a built in driver.

  • Page 106: Cdi Modules (E.g. Msd, Crane Etc.)

    5.3.5 CDI modules (e.g. MSD, Crane etc.) Typical CDI units provide a "white wire" trigger input that can be connected to the Megasquirt for ignition control. Follow the manufacturers installation instructions for the other wiring. Ensure that no other trigger inputs are connected (e.g.

  • Page 107: Mazda Rotary Ignition Wiring

    With the MSD ignition box, we use the white 'points' input wire. Do not connect anything to the green and violet wires. The MSD box is only being used to fire the coil. The Megasquirt must receive its tach input from a crank or distributor pick-up.

  • Page 108: Toyota Dli Ignition Wiring

    In the software settings ensure that "Toyota DLI" is selected. Set the Spark Output to Going High. Build circuit in section 5.3.1.3 IGc1 Spark A Toyota ignition IGdA coils Spark B IGc2 Megasquirt (4cyl) Customised for logic spark outputs (c) 2014-6 James Murray 2016-11-13 Page 108/222...
  • Page 109 MS3base/V3.0 Hardware Guide IGc1 Spark A Toyota IGdA ignition Spark B IGc2 Megasquirt coils IGdB (6cyl) Spark C Customised for IGc3 logic spark outputs (c) 2014-6 James Murray 2016-11-13 Page 109/222...

  • Page 110: 6: Ignition System - Specific Operating Modes

    For installations on engines without a supported tach input, a 36-1 trigger wheel on the crankshaft is the suggested setup. Here are all of the 'spark modes' supported by the Megasquirt-3 product range and whether they support wasted spark (W/S) and COP/seq (coil-on-plug or sequential fuel) or not on a 4-stroke engine. 2-stroke engines only need a missing tooth wheel on the crankshaft for sequential fuel and spark.
  • Page 111 MS3base/V3.0 Hardware Guide Spark Mode W/S ? Applications input /seq ? needed Renix 44-2-2 If cam Renault 4cyl, also V6 with 66-2-2-2 used Suzuki Swift* Distributor trigger wheel Suzuki Vitara 2.0* Suzuki Vitara 2.0 Daihatsu 3cyl* 3+1 cam trigger Daihatsu 4cyl* 4+1 cam trigger VTR1000* 12-3 on crank...

  • Page 112: Coil Negative For Fuel Only

    CDI type coil with a high primary voltage. Coil negative input CANNOT be used for installs using the Megasquirt to control ignition. Coil negative (not CDI)

  • Page 113: Distributor Pickup

    MS3base/V3.0 Hardware Guide 6.2 Distributor pickup The distributor is the traditional method of timing spark and distributing the high-tension spark voltage to individual spark plugs. Typically this used a set of breaker points, a condenser and a single ignition coil. Most distributors feature mechanical and vacuum advance systems to match spark timing somewhere close to optimal for different operating conditions.

  • Page 114: Input Phasing

    MS3base/V3.0 Hardware Guide Typical original arrangement Typical arrangement with ECU ignition timing control and locked distributor 6.2.2 Input phasing A typical distributor includes advance mechanisms which were originally used to control the timing. These are not used when using computer control and must be locked out to give a "locked" distributor. Correctly modifying an old distributor to give a reliable tach input may well be more difficult than adding a crank trigger wheel and will never be as accurate.
  • Page 115 HEI7/8, Bosch hall effect.) Align as per the factory manuals and determine how it is phased before you modify anything! The crank angle at which the tach input triggers is of importance and needs to be configured in the Megasquirt. For best spark control there are some optimal and some disallowed crank angles.

  • Page 116: Rotor / Output Phasing - All Distributor Installs

    MS3base/V3.0 Hardware Guide Allowed high angles Timing allowed in normal range (up to 5 degrees less than trigger angle.) Retarded ATDC timing possible. Disallowed angles. Do not use a trigger angle between 16 and 54 degrees. Timing will not work correctly. Distributor must be moved or re-phased.

  • Page 117: Distributor With Hall/Optical 'Trigger Return

    MS3base/V3.0 Hardware Guide When using the distributor for the tach input as well, beware of just rotating the distributor - that would change the input phasing that you already set - you may need to make a physical modification to rotate the rotor arm. (e.g.
  • Page 118 MS3base/V3.0 Hardware Guide A. Hall/opto distributor showing inactive trigger. B. Engine rotated forwards until edge at sensor. The crank angle here is the "Trigger Angle" C. Engine turned forwards some more. D. Engine turned forwards some more. This is the Return angle and needs to match your setting for cranking advance.

  • Page 119: Distributor With Basic Crank Trigger

    MS3base/V3.0 Hardware Guide The output phasing on an OEM trigger-return type distributor installed in the normal position should not require adjustment. Trigger-return can also be used with a latching hall sensor and pairs of magnets on a crank trigger. One pole (e.g.
  • Page 120 MS3base/V3.0 Hardware Guide The 'CCD' type is claimed to be black in color. and pin 4 runs as a diagnostic signal to the original ECU. These modules need standard dwell control e.g. 3ms instead of a fixed duty. Other wiring should be the same. Base Timing and phasing "Base Timing"...

  • Page 121: Gm Hei7

    The 'Est' signal from Megasquirt to the module controls the advance when running. The 'Bypass' signal from Megasquirt to the module allows the module to beneficially control its own advance during cranking. Once the engine has been running for more than 5 seconds, the Megasquirt takes control of timing.
  • Page 122 MS3base/V3.0 Hardware Guide Set the mainboard as per section 5.2.4 Make the following modifications: Add 1k 1/8W resistor from (-) of D14 to the right hand side of the resistor below. Add 1k 1/8W resistor from (-) of D16 to the right hand side of the resistor below. Jumper from (-) of D14 to IGN Jumper from (-) of D16 to SPR3 (or your chosen pin) (c) 2014-6 James Murray...

  • Page 123: Gm Hei8

    P = Positive from VR sensor N = Negative from VR sensor G = Ground to Megasquirt Sensor ground B = Bypass from Megasquirt bypass output (SPR3 shown) R = Reference (REF) to Megasquirt Tach in E = Electronic spark timing (EST) from Megasquirt IGN...

  • Page 124: Dual Sync Distributor

    A dual-sync distributor is an aftermarket locked distributor that provides a clean trigger signal for an ECU. The signal can be used for sequential fuel in some situations. As Megasquirt has only two fuel channels, it is simplest to ignore the "reference" signal from the distributor and configure as a regular distributor using "Basic Trigger."...

  • Page 125: Ford Edis

    MS3base/V3.0 Hardware Guide 6.7 Ford EDIS Ford's Electronic Distributorless Ignition System (EDIS) is an ignition system that does not require a cam position signal. It requires a variable reluctor (VR) sensor and a 36-1 tooth crank wheel (36-1 means '36 teeth minus one', and refers to 36 evenly spaced teeth, one of which has been removed), it will not work with other pattern wheels or hall sensors.

  • Page 126: Ecu Wiring

    MS3base/V3.0 Hardware Guide 6.7.2 ECU wiring Set the mainboard as per section 5.2.4. The following internal modifications are required: a) Ensure that Q16 is not fitted. b) Run a jumper wire from JS10 to IGN (c) 2014-6 James Murray 2016-11-13 Page 126/222...

  • Page 127: Module Wiring

    MS3base/V3.0 Hardware Guide Typical Settings Spark mode = "EDIS" Ignition capture = "Rising Edge" Spark output = "Going High" Spark A output pin = "JS10" 6.7.3 Module wiring The EDIS system comes in three varieties : EDIS4, EDIS6, EDIS8 which are suited to even-fire 4, 6, 8 cylinder engines.
  • Page 128 MS3base/V3.0 Hardware Guide (c) 2014-6 James Murray 2016-11-13 Page 128/222...

  • Page 129: Trigger Wheel And Vr Sensor

    MS3base/V3.0 Hardware Guide 6.7.4 36-1 trigger wheel and VR sensor The relationship of the VR sensor and the missing tooth is critical. The EDIS module expects and requires a specific phasing. On engines originally equipped with EDIS this will already be set. Later Ford engines also maintain the same phasing even though the EDIS function is now built into the ECU.
  • Page 130 MS3base/V3.0 Hardware Guide 6.7.4.2 EDIS4 - Clockwise rotation (normal) - method b Turn your engine to 90 BTDC. Mount the VR sensor wherever is convenient and mount trigger disc so that the center of the sensor aligns with the center of the missing tooth. 6.7.4.3 EDIS6 - Clockwise rotation (normal) - method a Set your engine at TDC, then put the missing tooth 6 teeth earlier (more clockwise) than the sensor.
  • Page 131 MS3base/V3.0 Hardware Guide 6.7.4.4 EDIS6 - Clockwise rotation (normal) - method b A different way of looking at the SAME phasing. Turn your engine to 60 BTDC. Mount the VR sensor wherever is convenient and mount trigger disc so that the center of the sensor aligns with the center of the missing tooth.
  • Page 132 MS3base/V3.0 Hardware Guide 6.7.4.6 EDIS8 - Clockwise rotation (normal) - method b Turn your engine to 50 BTDC. Mount the VR sensor wherever is convenient and mount trigger disc so that the center of the sensor aligns with the center of the missing tooth. (c) 2014-6 James Murray 2016-11-13 Page 132/222...

  • Page 133: Checking The Timing

    The same internal modifications are required as for HEI7 in section 6.4 This wiring need confirming. P = Positive from VR sensor N = Negative from VR sensor G = Ground to Megasquirt Sensor ground B = Bypass from Megasquirt SPR3 (c) 2014-6 James Murray 2016-11-13...

  • Page 134: Toothed Wheel

    MS3base/V3.0 Hardware Guide R = Reference (REF) to Megasquirt Tach in. E = Electronic spark timing (EST) from Megasquirt IGN (36) These settings need confirming. Ignition capture = "Falling" (check!) Spark output = "Going High" (check!) Spark A output pin = "LEDs Spark"...
  • Page 135 MS3base/V3.0 Hardware Guide Note - this table is for four-stroke piston engines. Two stroke or rotaries only need 360 degrees of information for full sequential and COP. Commonly used modes have detailed sections on how to set them up. Unusual modes are not documented in detail at this time.

  • Page 136: Terminology Notes

    Sequential - each injector fires once per engine cycle timed to a specific cylinder event 6.9.3 Wheel naming There does not appear to be universal agreement on the way to name wheels, however in the Megasquirt world, they will be named like the following examples.

  • Page 137: Retrofit Install

    For very high revving engines (such as motorcycle engines) due to the number of teeth per second, 36-1, 24-1 or 12-1 are preferred. (Megasquirt-3 can reliably support higher revs and more teeth than Megasquirt-2.) While the code can cope with any sensor/tooth phasing, during cranking the rpms vary up and down greatly as the engine rotates.

  • Page 138: Existing Install

    6.9.5 Existing install In this case where you are fitting Megasquirt to an engine already fitted with a trigger wheel, your main task is to wire up the sensor(s), determine the tooth #1 angle and wire up your coil(s). It should not normally be necessary to modify the trigger wheels.
  • Page 139 MS3base/V3.0 Hardware Guide Clockwise rotation (normal) - method Set your engine at TDC, then count the number of GAPS to tooth#1 in the direction of rotation (clockwise here) and multiply by the angular size of the tooth. e.g. 8 teeth * 10 deg/tooth = 80 deg 36-1 wheels are 10 deg per tooth 60-2 wheels are 6 deg per tooth 24-2 wheels are 15 deg per tooth...

  • Page 140: Missing Tooth Cam Wheel

    MS3base/V3.0 Hardware Guide 6.9.7 Missing tooth cam wheel This arrangement is not commonly used by OEMs but does support full sequential with a single wheel and sensor. Cam triggering is less accurate than crank triggering due to timing belt or chain stretch. The software benefits from a reasonable number of teeth (hence 36 or 60) for best ignition timing accuracy.
  • Page 141 MS3base/V3.0 Hardware Guide The definition of tooth#1 is the same as the basic missing tooth crank wheel and should be phased in the same way. Ensure you also read the section above. The cam input tells the code which engine cycle/phase it is on. From the crank wheel alone the code knows when cylinder one is at TDC, but it cannot distinguish TDC compression or TDC exhaust.
  • Page 142 MS3base/V3.0 Hardware Guide First, set your engine at TDC compression #1 Now rotate the engine backwards to tooth#1 The angle read off the damper is the tooth#1 angle (c) 2014-6 James Murray 2016-11-13 Page 142/222...

  • Page 143: Missing Tooth Crank Wheel And Polled Cam Wheel

    'looks at' (polls) the cam just after the missing tooth to determine engine phase. The wide/narrow type is used for VVT control on some engines and is supported by Megasquirt-3. (c) 2014-6 James Murray...
  • Page 144 MS3base/V3.0 Hardware Guide Typical polled cam triggers: 4 tooth wide/narrow type e.g. GM LS2 4X / VW / Mercedes Vane cup with single window e.g. 1 window Bosch dizzy in Vauxhall red-top. Half-moon type (c) 2014-6 James Murray 2016-11-13 Page 144/222...
  • Page 145 MS3base/V3.0 Hardware Guide General arrangement The definition of tooth#1 is the same as the basic missing tooth crank wheel and should be phased in the same way. The cam input tells the code which engine cycle/phase it is on. From the crank wheel alone the code knows when cylinder one is at TDC, but it cannot distinguish TDC compression or TDC exhaust.
  • Page 146 The cam sensor should be roughly in the middle of window/tooth/vane With the cam sensor powered and connected to the Megasquirt measure the output voltage. A voltage of ~0V here requires the HIGH setting and a voltage of ~5V here requires the LOW setting.

  • Page 147: Nippondenso Cas

    MS3base/V3.0 Hardware Guide Now rotate the engine backwards a full revolution. The cam sensor will be opposite that previous window/tooth/vane. (If there was a window before it must be a vane now and vice- versa.) Typical settings: Spark mode = Toothed wheel Trigger angle/offset = 0 (not used in toothed wheel mode) Trigger wheel arrangement = Dual wheel with missing tooth Trigger wheel teeth = number of teeth including missing teeth (e.g.
  • Page 148 MS3base/V3.0 Hardware Guide (c) 2014-6 James Murray 2016-11-13 Page 148/222...
  • Page 149 MS3base/V3.0 Hardware Guide CAS connection Megasquirt connection NE- / GND Pin 2 / GND Tach in G1 or G2 Cam input (mods req'd) Other G not used 6.9.10.1 NipponDenso CAS with single G tooth With the single tooth every 720 degrees this setup gives enough engine information for full sequential fuel and spark.
  • Page 150 MS3base/V3.0 Hardware Guide Now rotate the engine backwards until the 'cam' sensor and tooth line up. If you rotated more than one turn, then add 360 to your tooth#1 angle. Now rotate the engine forwards until the next 'crank' tooth aligns with its sensor.
  • Page 151 MS3base/V3.0 Hardware Guide 6.9.10.2 NipponDenso CAS with two G teeth With the cam tooth every 360 degrees this setup gives enough engine information for semi-sequential fuel and wasted spark. (On a rotary such as the RX7, or a two-stroke engine, full sequential fuel and spark is possible as the engine cycle spans 360 degrees.) What is Tooth #1 With the engine rotating in the normal direction...

  • Page 152: Non-Missing Tooth Crank Wheel With One Cam Tooth

    MS3base/V3.0 Hardware Guide 6.9.10.3 NipponDenso CAS with three or four G teeth This version is used on three and four cylinder engines with one G tooth per cylinder. There is only enough position information to run a distributor and untimed injection. It is not strictly necessary to use both Ne and G wheels.
  • Page 153 Generally Megasquirt benefits from many crank teeth to improve ignition timing accuracy. However, with this wheel arrangement, you need to beware of trying to use too many teeth on the crank as there is a risk of the trigger inputs overlapping as the cam belt or chain stretches.
  • Page 154 MS3base/V3.0 Hardware Guide First, set your engine at TDC compression Now rotate the engine backwards until the cam sensor and tooth line up. If you rotated more than one turn, then add 360 to your tooth#1 angle. (c) 2014-6 James Murray 2016-11-13 Page 154/222...

  • Page 155: Mitsubishi Cas With Aftermarket Disc - Single Coil / Wasted Spark

    MS3base/V3.0 Hardware Guide Now rotate the engine forwards until the next crank tooth aligns with its sensor. The crank angle now is the tooth#1 angle. (Note that angles shown in diagram are examples only) Typical settings: Spark mode = Toothed wheel Trigger angle/offset = 0 (not used in toothed wheel mode) Trigger wheel arrangement = Dual wheel Trigger wheel teeth = number of teeth...

  • Page 156: Mitsubishi Cas With Aftermarket Disc - Coil-On-Plug

    MS3base/V3.0 Hardware Guide Set the mainboard as per section 5.2.3 Switched 12V Sensor Sensor GND Megasquirt Outer Inner Tach in Typical settings: Spark mode = Toothed Wheel Trigger Angle/Offset = 0 (not used) Ignition input capture = ???? Spark Output = Depends on coils / ignitors...

  • Page 157: Other Wheel Arrangements

    36-1 crank wheel and a VR sensor. Set the mainboard as per section 5.2.2. A high-current coilpack is used and requires two high current ignition outputs - see section 5.3.1.2. Megasquirt-3 only needs the crank signal to run wasted-spark and batch fire fuel, this is the simplest configuration.

  • Page 158: Neon/420A

    1995-2000 Dodge Avenger The crank and cam signal pattern looks as follows: Megasquirt-3 only needs the crank signal to run wasted-spark and batch fire fuel, this is the recommended configuration without the MS3X. (Connecting and configuring the cam signal would allow coil-on-plug ignition with suitable coils.)
  • Page 159 MS3base/V3.0 Hardware Guide The following diagram shows the recommended wiring using internal high current drivers to drive the standard 420A high-current coilpack. It requires two high current ignition outputs - see section 5.3.1.2 Alternative #1: Use an external 2 channel ignitor and customise the mainboard for logic spark outputs as per section 5.3.1.3 Alternative #2: use a logic wasted spark coil pack such as the VW item (032 905 106B) shown in section: 5.3.2 instead of the stock coilpack and customise the mainboard for logic spark outputs as per section 5.3.1.3...

  • Page 160: Ngc)

    MS3base/V3.0 Hardware Guide Typical settings: Spark mode = 420A Trigger Angle/Offset = 0 (tweak if required) Ignition input capture = Rising edge Spark Output = Going High Number of coils = Wasted Spark Injectors are wired up using the general diagram in section 4.10.2.1. Connect injectors 1 & 4 to bank 1 and injectors 2 &...
  • Page 161 MS3base/V3.0 Hardware Guide Megasquirt-3 only needs the crank signal to run wasted-spark and batch fire fuel, this is the recommended configuration without MS3X. Set the mainboard as per section 5.2.3. Four cylinder example : The following diagram shows the recommended wiring using internal high current drivers to drive the standard high-current coilpack.
  • Page 162 MS3base/V3.0 Hardware Guide Typical settings: Spark mode = 36-2+2 Trigger Angle/Offset = 0 (tweak if required) Ignition input capture = Rising Edge Spark Output = Going High Number of coils = Wasted Spark Injectors are wired up using the general diagram in section 4.10.2.1. Connect injectors 1 & 4 to bank 1 and 2 & 3 to bank 2.

  • Page 163: Miata 99-05

    MS3base/V3.0 Hardware Guide See the generic instructions in section 5.2 and 5.2.2. Mazda RX8 engines RX8 engines use rotary specific coils - see section 5.3.6 for wiring. Typical settings: Spark mode = 36-2-2-2 Trigger Angle/Offset = 0 (tweak if required) Ignition input capture = Falling Edge (typically) Spark Output = Going High Number of coils = Coil on Plug...

  • Page 164: Subaru 6/7

    MS3base/V3.0 Hardware Guide 6.14 Subaru 6/7 This mode is designed for the EJ series engines with the unique "6/7" trigger - there are six unevenly spaced teeth on the crank wheel and seven teeth in total on the cam sprocket for cylinder identification. Both crank and cam inputs need to be connected..

  • Page 165: Iaw Weber

    MS3base/V3.0 Hardware Guide Switched 12V Sensor Sensor GND Outer Megasquirt Tach Inner Later 6G72 use two independent sensors on crank and cam, but the signal pattern to the ECU is the same. See sections 5.2.3 and 5.2.14.2 for mainboard modifications.

  • Page 166: Mitsubishi Cas 4/1

    • Mazda Protege and 323 with optical distributor • Switched 12V Sensor Sensor GND Outer Megasquirt Tach Inner See sections 5.2.3 and 5.2.14.2 for mainboard modifications. Typical settings: Spark mode = CAS 4/1 Trigger angle/offset = 0 (adjust with strobe)
  • Page 167 The outer track is considered to be the 'crank' signal and the inner track is the 'cam'. Switched 12V Sensor Sensor GND Outer Megasquirt Tach Inner Later 4G63 use two independent hall sensors with a two tooth crank trigger and a two tooth cam trigger, but the (c) 2014-6 James Murray...

  • Page 168: Twin Trigger

    Number of coils = Wasted Spark Most Miata/MX5 of this era use a logic wasted spark coilpack which can be directly connected to the Megasquirt. 6.19 Twin trigger The twin-trigger mode is designed primarily for 4-cylinder bike engines using a pickup similar to the photo. There is a single tooth and two pickup coils.

  • Page 169: Chrysler 2.2/2.5

    (The TBI versions of this engine used Basic Trigger mode instead.) It uses a four tooth cam trigger with a “window” in the middle of one tooth and two hall sensors. Only one hall sensor is used by Megasquirt, connect to Tach in. Set the mainboard as per section 5.2.3. Typical settings: Spark mode = Chrysler 2.2/2.5...

  • Page 170: Suzuki Vitara 2.0

    MS3base/V3.0 Hardware Guide Ignition input capture = Set according to whichever edge gives the most stable signal. (If timing advances with RPM, try flipping it.) Spark output = Going high Number of coils = Single coil 6.23 Suzuki Vitara 2.0 Known applications include: Vitara 2.0 •...

  • Page 171: Rover#1

    MS3base/V3.0 Hardware Guide Some Honda V-twin motorcycles • It uses a 12-3 crank trigger with a VR sensor and no cam sensor. Typical settings: Spark mode = VTR1000 Trigger angle/offset = 0 (adjust with strobe) Ignition input capture = Set according to whichever edge gives the most stable signal. (If timing advances with RPM, try flipping it.) Spark output = Going high Number of coils = Wasted spark...

  • Page 172: Gm7X

    MS3base/V3.0 Hardware Guide Similar to Rover #2, but the gaps are two teeth wide and positioned differently. As with Rover #2, supports wasted spark and semi-sequential injection, but does not support cam input. Typical settings: Spark mode = Rover#3 Trigger angle/offset = 0 (adjust with strobe) Ignition input capture = Set according to whichever edge gives the most stable signal.
  • Page 173 MS3base/V3.0 Hardware Guide Only the crank sensor is used with Megasquirt-3 without MS3X. Set the mainboard as per section 5.2.4. Mainboard customisation is required for four logic spark outputs. It is preferable to use the MS3X on the 24X engine as it gives full sequential and a more straightforward install.

  • Page 174: Gm Ls2 (58X)

    6.34 GM LS2 (58X) Known applications include: Chevrolet V8s of LS2 family using a 58X crank pattern. (Typically Gen 4.) • Only the crank sensor is used with Megasquirt-3 without MS3X. Set the mainboard as per section 5.2.3. (c) 2014-6 James Murray 2016-11-13...

  • Page 175: Yzf1000

    MS3base/V3.0 Hardware Guide Mainboard customisation is required for four logic spark outputs. It is preferable to use the MS3X on the 24X engine as it gives full sequential and a more straightforward install. The coils are wired in pairs SpkA = 1&6, SpkB = 8&5, SpkC = 7&4, SpkD = 2&3. Coil wiring is shown in section 6.33 Typical settings: Spark mode = Toothed wheel...

  • Page 176: Hd 32-2

    MS3base/V3.0 Hardware Guide 6.36 HD 32-2 Known applications include: Harley Davidson with 32-2 crank trigger • A VR sensor is used on the crank trigger. As standard there is no cam sensor. Phase detection is possible using the MAP sensor. Typical settings: Spark mode = HD 32-2 Trigger angle/offset = 0 (adjust with strobe)

  • Page 177: Gm Optispark

    The Optispark requires a fused 12V supply. This can be tapped into the same 12V supply as the Megasquirt. The Ground connection should be run to the sensor ground at the Megasquirt.

  • Page 178: Nissan Sr20

    MS3base/V3.0 Hardware Guide Set the mainboard as per section 5.2.3 Typical settings: Spark mode = Basic Trigger Trigger angle/offset = Start at 10 deg - adjust while strobing timing. Ignition input capture = Falling edge Number of coils = Single coil 6.40 Nissan SR20 This is not covered as full sequential requires input PT4 to be connected through the MS3X.

  • Page 179: Jeep 2002

    MS3base/V3.0 Hardware Guide This mode has thee sets of four notches on the crank trigger and a one tooth distributor trigger. Requires crank and cam sensors to be connected. Typical settings: Spark mode = Jeep 2000 Trigger angle/offset = 0 (adjust with strobe) Ignition input capture = Set according to whichever edge gives the most stable signal.

  • Page 180: 2Jz Vvti

    MS3base/V3.0 Hardware Guide 1986 and earlier BMW 325e • E30 chassis BMW M3 with S14 motor • Many 1980s and early 1990s Audis • This application uses a VR sensor that counts flywheel teeth, with a second flywheel sensor that reads a single post and, in most implementations, a cam sensor.

  • Page 181: Mazda6 2.3 Vvt

    MS3base/V3.0 Hardware Guide D17 engine • Uses a 12 tooth crank sensor with one tooth added for a total of 13 real teeth, combined with a cam sensor. This allowed Honda to add continuously variable valve timing. Uses VR sensors. Both sensors need to be connected for VVT.

  • Page 182: Honda K24A2

    MS3base/V3.0 Hardware Guide Coil-on-plug is beyond the scope without MS3X, so wasted spark should be used. Factory Chrysler coils are high-current type and require internal or external ignitors. Typical settings: Spark mode = Viper V10 Gen1 Trigger angle/offset = 0 (adjust with strobe) Ignition input capture = Set according to whichever edge gives the most stable signal.

  • Page 183: 7: Throttles

    MS3base/V3.0 Hardware Guide 7: Throttles The major influence on engine speed on a spark-ignition (gasoline) engine is air-flow. (Contrast a compression- ignition (diesel) engine where there is no throttling and fuel flow governs engine speed.) For normal running the main throttle plates control the air-flow. At idle an idle valve can be used to provide controlled flow, or a throttle stop screw can be used on the main throttles to allow a low flow during "closed"...

  • Page 184: 8: Optional Hardware

    8: Optional Hardware 8.1 Expansion boards The Megasquirt was designed with enough inputs and outputs to control a simple engine. If additional inputs and outputs are desired, an add-on expansion board may be used. The Megasquirt has CAN communications that allow the simple 2-wire connection.
  • Page 185 MS3base/V3.0 Hardware Guide (c) 2014-6 James Murray 2016-11-13 Page 185/222...

  • Page 186: 10: Further Information

    9.2 Component pinouts The following are some typical component pinouts that may be of use while adding additional circuits. 10: Further information For additional information or to join the community forums for Megasquirt, please visit: www.msextra.com 11: Appendix A Schematics The copyrighted Megasquirt schematics are provided for repair, interfacing and education purposes only.
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  • Page 195 MS3base/V3.0 Hardware Guide There are no plans to publish the schematics for the MS3 card. (c) 2014-6 James Murray 2016-11-13 Page 195/222...
  • Page 196 MS3base/V3.0 Hardware Guide Relay Board (c) 2014-6 James Murray 2016-11-13 Page 196/222...
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  • Page 198: 12: Appendix B: Junkyard Guide To Finding Edis

    MS3base/V3.0 Hardware Guide 12: Appendix B: junkyard guide to finding EDIS 12.1 North America - EDIS4 Early to mid 1990s Ford Escort/ Mercury Tracer with base 1.9L SOHC engine were fitted with the EDIS4 system. You can tell the engine because it has a tubular aluminium (NOT cast) inlet manifold. The EDIS4 module is mounted just behind the fuse box on the drivers side of the engine bay, it has a label on the plug that says EDIS4.

  • Page 199: Europe - Edis4

    MS3base/V3.0 Hardware Guide 12.2 Europe - EDIS4 1989-1993 Fiesta XR2i 1.6 1990-1992 Fiesta RS turbo 1989-1994 Escort 1.6i 1990-1994 Orion 1.6i Modules are all in the engine bay and typically located in the middle of the bulkhead or the right hand side as you face the car.
  • Page 200 MS3base/V3.0 Hardware Guide Mondeo with 1800/2000 engine. Location of the VR sensor varies. On the small CVH engines it pokes through the rear flange of the engine towards the flywheel. 1.8CVH Sierra has one on the front. 2.0DOHC Sierra/ Granada is in the block at the left side way below the inlet manifold.

  • Page 201: Europe - Edis6

    MS3base/V3.0 Hardware Guide 12.3 Europe - EDIS6 up to 1995ish Mondeo V6 automatic Ford/Cosworth Granada Scorpio 24v V6 Module located rear left of engine bay as you face the car. Known part numbers are: 90GB-12K072-AB 12.4 Europe - EDIS8 Chances of finding one of these in a scrapyard are very low! Not known to have been installed on any European built vehicles.

  • Page 202: Europe - Vr Sensor

    MS3base/V3.0 Hardware Guide 12.6 Europe - VR sensor Usually it is easiest to get from the same vehicle as the EDIS module so the wiring harness wiring colors match. Or any vehicle with a trigger disc will yield one, so CVH Fiesta/Escort/Orion or Fiesta with Valencia (crossflow) engine with ESCII hybrid, DOHC Sierra/Granada, Mondeo.

  • Page 203: 13: Appendix C: V3.0 Board Assembly

    This manual page is primarily intended to help you through the DIY soldering together of the V3.0 mainboard. If you bought a pre-assembled Megasquirt, then this should all be covered. This may also be of use if you are changing the installation of a Megasquirt and need to alter the tach input.

  • Page 204: Assembly

    MegaSquirt kit supplier. (While it is possible to buy all the parts individually, for a single Megasquirt build this is likely to be extremely time consuming and not worth the effort - just buy a complete kit, really.) 2) Clear space on a work bench with good lighting.
  • Page 205 MS3base/V3.0 Hardware Guide Find R12, R37, R38, R43, R39 and R57. Put them out of the way for the moment as you don’t need them yet. R57 is never needed and should not actually be part of the kit. 5) Now solder all of the rest of the ordinary resistors in place - soldering from the top. Note: There is no polarity for resistors, so they can fit in either way round.
  • Page 206 MS3base/V3.0 Hardware Guide (c) 2014-6 James Murray 2016-11-13 Page 206/222...
  • Page 207 MS3base/V3.0 Hardware Guide 12) Next get all the bags of capacitors together, keeping them in the bags (C1, etc). If you’re using the coil –ve as the trigger input go to step 14 (This is rare now.) Note that you CANNOT trigger from coil negative if you are trying to run ignition or sequential fuel - you need a toothed-wheel arrangement.
  • Page 208 17) Find Q16, (Ignition Transistor), D14, D15 and D16 (LEDs) Q4 and Q20 (small transistors) and MS3 CPU card. Put these to one side but don’t lose them!!
  • Page 209 MS3base/V3.0 Hardware Guide Without mica With mica (c) 2014-6 James Murray 2016-11-13 Page 209/222...
  • Page 210 MS3base/V3.0 Hardware Guide 19) Find Y1 (crystal) This is not needed for MS3, but for completeness you can fit it so that the body of the crystal lays on the metal pad above the holes. You should glue this to the board or very carefully solder it so it doesn't move about.

  • Page 211: Jumper Wires

    MS3base/V3.0 Hardware Guide case will distort and read incorrectly. This is installed with the writing facing you, the 'round' side goes towards the board. One of the pins has a small notch out of it which goes in the hole with 'notch' next to it. Don't forget to install Q22, Q23.
  • Page 212 MS3base/V3.0 Hardware Guide It is strongly recommended that these jumper wires are all installed as described, unless you are using the outputs for a custom modification. CAN jumpers - top side of board. JS6 to SPR1 (CANH) JS8 to SPR2 (CANL) S12C-JS9 - bottom side of board This is required to power the stepper driver.

  • Page 213: Testing Stage

    MS3base/V3.0 Hardware Guide 13.5 Testing Stage 24) The board is now built to a basic level and is ready for a few tests: a) Start by looking at ALL of the diodes and ensure they are the right way round. b) Check that you fitted the mica insulators under Q9 and Q12 on the heatsink and that they look OK.
  • Page 214 26) Idle valves: The MS3 card has support for a 4 wire stepper idle valve built-in, just requiring the five jumpers on the mainboard in step 23. If using 2 wire PWM idle, you will need to upgrade the 'FIDLE' circuit on the V3.0 board. (The PWM Idle Valve circuit upgrade can also be used to drive other solenoids such as boost control.)
  • Page 215 30) Now your ready to test the board with the microprocessor in place. Fit the MS3 CPU card into socket U1. Note that it is normal for some of the pins on the large square chip on the MS3 card to appear 'bridged'.
  • Page 216 MS3base/V3.0 Hardware Guide Side view of completed assembly Lower view Top view Plug the ECU into your stim and turn the power on. Feel the top row of power transistors, if they get hot at all turn the power off and check for faults. If the microprocessor gets hot then turn it off.
  • Page 217 MS3base/V3.0 Hardware Guide Installing the circuit board into the case in the third slot up. 3rd slot up Having slotted the assembly into the case, screw in the four endplate to case retaining screws. The connector hex bolts may now be tightened up. The USB end end-plate may now be fitted, screwed onto the case body and the hex bolts fitted.

  • Page 218: Bill Of Materials (Parts List)

    MS3base/V3.0 Hardware Guide 32) You are now ready to load the MS3 firmware and follow the other steps in the Quickstart guide contained within the Setting Up Manual. 13.6 Bill of Materials (parts list) Here are the parts used to assemble the V3.0 main board.
  • Page 219 MS3base/V3.0 Hardware Guide Desc. Part no. Notes C24* Capacitor 47PF 200V 5% CER 399-1911-ND MS1 only RADIAL C25* Capacitor 22PF 200V 5% CER 399-1908-ND MS1 only RADIAL C4,C6,C8,C12,C15 Capacitor 0.001µF 100V 10% CER 399-4202-ND RADIAL - X7R C5,C7 Capacitor 1.0µF 50V 10% CER 399-2102-ND or 399- RADIAL - X7R 4389-ND...
  • Page 220 MS3base/V3.0 Hardware Guide Desc. Part no. Notes Q22,Q23 Transistor PNP 100V 1000MA TO- ZTX553-ND Q3,Q11 Transistor PNP 6A 100V HI PWR 497-2629-5-ND TO220AB Q6,Q7,Q8,Q10,Q13, Transistor NPN SS GP 200MA TO- 2N3904FS-ND Q14,Q15,Q19,Q20 Q9,Q12 Transistor PNP DARL -100V -5A TIP125TU-ND Active flyback TO-220 R16,R19,R26,R27, Resistor 1.0K Ohm 1/8W 5%...
  • Page 221 AE7300-ND or Optional GOLD (4N25) AE10021-ND socket Connector DB-37 Female; 237F-ND Cables DB-37 Hood; 937GM-ND Cables * = MS1 only. The 32kHz crystal and circuit are not used on MS2 or MS3 installs. (c) 2014-6 James Murray 2016-11-13 Page 221/222...

  • Page 222: 14: Revision History

    MS3base/V3.0 Hardware Guide 14: Revision history 2014-08-05 First revision. 2014-08-11 Flip 4G63 tach-in. Add note about tach-in polarities for ref. 2014-08-14 MAP sensor diagram. Optispark for basic trigger. 2014-08-28 Updated external wiring diagram and colors. Add extra i/o table. Speed sensor inputs. Enable automatic numbering - there may be some incorrect section refs.

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