Link G4 Storm User manual

Link G4 Storm
Link G4 Xtreme
Copyright 2009
Link ElectroSystems Ltd
Wiring & Installation
Manual

G4 Wiring and Installation Manual2
© 2009 Link
Table of Contents 0
Part I Introduction 4
...................................................................................................................................41Support Options
Part II Choosing a Configuration 5
...................................................................................................................................51Injector Outputs
...................................................................................................................................62Ignition Outputs
...................................................................................................................................63AuxiliaryOutputs
...................................................................................................................................74 Analog/Temperature Inputs
...................................................................................................................................75Digital Inputs
...................................................................................................................................86Trigger Inputs
...................................................................................................................................87Summary
...................................................................................................................................108Installer IO Table
Part III Component Installation Locations 12
...................................................................................................................................121ECU Location
...................................................................................................................................122Ignition Component Placement
...................................................................................................................................133MAP Sensor Location
Part IV Storm Header Pinout 13
Part V Xtreme Header Pinout 14
Part VI Power and Ground Wiring 15
...................................................................................................................................151Power Supplies
...................................................................................................................................162+14V In
...................................................................................................................................163+14V Aux9/10
...................................................................................................................................174Power Ground
...................................................................................................................................175Sensor Ground
...................................................................................................................................176 +5V Out
...................................................................................................................................177 +8V Out
...................................................................................................................................188ECU Hold Power Wiring
Part VII Input Signal Wiring 19
...................................................................................................................................191Trigger Inputs
.......................................................................................................................................................... 20Reluctor/Magnetic Sensors
.......................................................................................................................................................... 21Hall/Optical/Proximity Sensors
...................................................................................................................................222MAP Sensor
...................................................................................................................................243TPS Wiring
...................................................................................................................................254Engine Coolant Temperature Sensor
...................................................................................................................................255Intake Air Temperature Sensor
...................................................................................................................................266Narrow Band Oxygen Sensor
...................................................................................................................................277 Wide Band Oxygen Sensor

3Contents
3
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...................................................................................................................................278 GP Pressure & Temperature Sensing
...................................................................................................................................289Digital Input Wiring
Part VIII Output Wiring 29
...................................................................................................................................291Fuel Injector Drives
.......................................................................................................................................................... 30High Impedance Injectors
.......................................................................................................................................................... 30Low Impedance Injectors
.......................................................................................................................................................... 31Injection Mode
...................................................................................................................................332Ignition Drives
.......................................................................................................................................................... 33Igniter Requirements
.......................................................................................................................................................... 34Coil Requirements
.......................................................................................................................................................... 35Ignition System Wiring
.......................................................................................................................................................... 35Distributor Ignition
.......................................................................................................................................................... 36Multi-Coil Wasted Spark Ignition
.......................................................................................................................................................... 38Multi-Coil Direct Spark Ignition
...................................................................................................................................383Auxiliary Output Wiring
.......................................................................................................................................................... 39Low Side Driving (Switching To Ground)
.......................................................................................................................................................... 40High Side Driving (Switching Power Supply)
.......................................................................................................................................................... 40Switching Through a Relay
.......................................................................................................................................................... 41Switching an LED
...................................................................................................................................414Idle Speed Control
.......................................................................................................................................................... 42Two Terminal ISC Solenoid
.......................................................................................................................................................... 43Three Terminal ISC Solenoid
.......................................................................................................................................................... 43Four Terminal ISC Stepper Motor
.......................................................................................................................................................... 44Six Terminal ISC Stepper Motor
...................................................................................................................................455Tachometer
...................................................................................................................................456Variable Valve Timing (VVT) Solenoids
...................................................................................................................................467Electronic Throttle Control
Part IX Rotary Engine Wiring 46
...................................................................................................................................471 Rotary Injection Wiring
...................................................................................................................................472Rotary Ignition Wiring
...................................................................................................................................483Metering Oil Pump Wiring
Part X PC Tuning 49
...................................................................................................................................491 Installing USB Drivers
...................................................................................................................................492Installing PCLink Tuning Software
...................................................................................................................................503Communicating With Your ECU
Part XI First Time Setup 50
...................................................................................................................................511Pre-start Checks
...................................................................................................................................512Initial Setup
...................................................................................................................................573Trigger Calibration
...................................................................................................................................584First Time Startup
...................................................................................................................................605 Essential Tuning Adjustments
Index 62

G4 Wiring and Installation Manual4
© 2009 Link
1Introduction
Thank you for purchasing your Link Wire-In Engine Control Unit (ECU). Link G4 ECU's are
an advanced, fully programmable microprocessor controlled Engine Management System.
The G4 software platform boasts an impressive list of features giving a new level of user
adjustment. This flexibility allows the tuner to have complete control over the engine
management system. G4 software employs high resolution fuel and ignition tables with
configurable load and RPM centres. Coupled with up five dimensional fuel and ignition
mapping, barometric pressure compensation and intake air temperature correction this gives
an unprecedented level of tuning accuracy. G4 ECU's are in field upgradeable, no need to
return the ECU for software updates.
All Link G4 Wire-In Engine Management Systems are designed with flexibility and ease of
installation in mind. LinkWire-In systems are deigned to be wired to either existing wiring or
preferably as a complete re-wire. In some cases adapter looms or header boards can be
purchased to allow wiring of the G4 ECU to factory ECU headers. Contact your nearest Link
dealer for more information on these.
Link Engine Management Systems are designed with the final result in mind. Not only do
they boast an impressive range of performance features, but are designed with a focus on
safety, reliability and drive-ability. However, the ultimate success of your engine
management upgrade is determined by how well the system is installed and tuned.
Installing and tuning any after-market engine management system is not to be taken lightly.
G4 ECU's give the tuner the control & flexibility that only top after-market engine
management systems in the world can provide. While every effort has been made to keep
G4 ECU's as user friendly as possible, it should be recognised that added features bring
added complexity.
The complete set-up of your ECU can be divided into two equally important tasks.
1. This manual covers the wiring and installation of your G4 ECU. While it is not strictly
essential that this work is performed by an automotive electrician, the knowledge and
tools available to these professionals makes it highly recommended. Regardless of who
does the installation, it is of utmost importance that clean and robust connections are
made throughout the installation. A significant majority of after market engine
management failures are due to poor wiring practices. Note that use of complex features
such as Variable Valve Timing, Electronic Throttle Control and ECU Hold Power require
advanced wiring practice.
2. Once the G4 ECU has been installed it will need to be tuned using a laptop computer
with PCLink Tuning Software software. Information on the configuration and tuning of
the G4 ECU is detailed in the online help section of PCLink Tuning Software. G4 ECU's
are shipped pre-loaded with a base configuration that should be close enough to get
most engines running after a few application specific adjustments have been made.
While hearing the engine running on the new ECU for the first time is always a satisfying
feeling, it is important to realise that the job is not complete. The amount of tuning
performed and the experience of the tuner are the two most important factors in
determining how happy you will be with your engine management system.
1.1 Support Options
Should any issues arise during installation, the following options exist for technical support:
1. Contact your nearest Link dealer. A Link dealer list is available on our website: www.
LinkECU.com

Introduction 5
© 2009 Link
2. Technical Support Email: [email protected]
3. Online Discussion Board: Available from the Link website.
The majority of questions received by the technical support team are clearly answered in
the manuals. To speed up your technical inquiry please consult the manuals to make sure
that your question has not already been answered.
2Choosing a Configuration
As all G4 inputs/outputs are configurable, the required connections will be highly dependent
on the application. Read this section carefully to ensure the correct functions are chosen.
The first step in installing a G4 ECU is to decide what function each of the configurable
inputs and outputs will provide.
The G4 ECU's have the following input / output pins:
IO
Storm
Xtreme
Injection Drives
4 x Saturated
8 x Peak & Hold
Ignition Drives
4
8
Auxiliary Outputs
8
10
Digital Inputs
3 or 4*
10
Analogue Voltage Inputs
3/4* + Internal MAP
11
Temperature Inputs
2
4
Knock Sensor Inputs
0
2
Regulated Outputs
+8V & +5V
+8V & +5V
Trigger Inputs
2
2
* Storm shares one header pin for DI4 and An Volt 2
2.1 Injector Outputs
The Xtreme has eight independent current controlled (Peak and Hold) injector drives
allowing sequential, sequential staged, group and group staged fuel injection. These
injection drives are designed to be used with low or high impedance injectors without the use
of ballast resisters. Unused Injection channels can be used for additional auxiliary outputs.
The Storm has four independent saturated injector drives allowing sequential, group and
group staged fuel injection. These injection drives are designed to be used with high
impedance injectors. Injector ballast resistors must be wired if low impedance injectors are
to be used. Unused Injection channels can be used for additional auxiliary outputs.
G4 Injection Specifications:
·Max Peak Current = 10 A
·Max Hold Current = 3 A
·Max Saturated Injection or Auxiliary Output Current = 5 A
·Open Collector (not fly-wheeled) in auxiliary output mode.

G4 Wiring and Installation Manual6
© 2009 Link
2.2 Ignition Outputs
The Xtreme offers eight independent ignition drives which can be used in a wide range of
configurations from a basic distributor set-up through to more complex multi-coil
arrangements. Unused ignition channels can be used for additional auxiliary outputs (simple
switching functions only). All direct spark, wasted spark and distributed ignition
configurations requiring up to eight channels are supported by the Xtreme
The same as above applies for the Storm however the Storm has four ignition outputs.
G4 Ignition Specifications:
·Ignition Drive High 20mA @ 5V
·Ignition Drive Low 2A over current protected
·Open Collector (not fly-wheeled) in auxiliary output mode.
2.3 AuxiliaryOutputs
G4 Wire in ECU's have eight general purpose auxiliary outputs. Unused ignition and
injection channels can also be used as auxiliary outputs. Auxiliary outputs are general-
purpose outputs that may be used to perform a wide range of functions. However, the
following limitations apply:
·A Three Terminal ISC Solenoid must be wired to Aux 1 and Aux 2.
·An ISC Stepper Motor must be wired to Aux 5, Aux 6, Aux 7 and Aux 8.
·Variable Valve Timing (VVT) solenoids must be wired to Aux 1 to 4.
·Aux 5 to 8 can not be Pulse Width Modulated (PWM) above 300Hz. Note that PWM
frequencies above 300 Hz may be required to drive a tachometer for a V8 above
4500 RPM.
·An electronic throttle motor must only be wired to Aux 9 (+) and Aux 10 (-).
·Spare Injection and Ignition channels when used as auxiliary outputs can only be
used as Auxiliary Outputs.
Auxiliary outputs supply an earth to switch loads such as a solenoid, relay, bulb or LED. All
auxiliary outputs may be used as a conditional switch that becomes activated at a certain
value (e.g. Honda VTEC), or for more complex control operations such as as idle speed
control and electronic boost control.
Loads may be connected directly to the auxiliary output without using a relay provided they
do not draw more than 2A of current. Essentially this means that a directly connected load
should have a resistance exceeding 7O. Refer to the section on wiring auxiliary outputs.
Some of the functions that may be performed by auxiliary outputs include:
·Fuel Pump Relay Switching (highly recommended for safety reasons)
·Engine Coolant Fan Relay Switching
·Electronic boost control using a boost control solenoid (uses PWM)
·Variable valve timing solenoid (e.g. VTEC)
·Warning / Check Engine Light
·Purge Control
·EGR Control
·Any function requiring an output activated by temperature, manifold pressure (MAP),
RPM, gear position, digital input state etc.
·Water Injection / nitrous oxide control (uses PWM)
·Inter-cooler Water Spray
·Air Conditioning Clutch / Fan
·General Purpose PWM

Choosing a Configuration 7
© 2009 Link
·Idle Speed Control solenoids or stepper motors
·Electronic Throttle Control
G4 Auxiliary Output Specifications:
·1.5k Ohm Internal Pull-up Resister
·Auxiliary Drive Low 2A over-current protected
·Open Collector (fly-wheeled) in auxiliary output mode.
·Aux 5 to 8 High Side Drive (ISC Stepper Mode) 0.5 A.
·Aux 9 and 10 (Xtreme only) Push-Pull drive 4/4 A.
2.4 Analog/Temperature Inputs
G4 ECU's have plentiful analogue voltage and analogue temperature channels. The
difference between volt and temperature channels is temperature channels have an internal
pull-up resister.
All analogue volt channels are created equal and can be wired to any type of analogue input
(there is no restrictions as to what must be wired to each channel).
Analogue Volt Inputs may be configured to accept an analogue signal between 0-5V.
Applications include:
·Narrow-band O2 (0-1V output)
·Wide-band O2 (via external wide-band controller)
·0-5V Voltage (e.g. Boost Adjust)
·Pressure (from 0-5V transducer)
Temperature channels are designed to be used only with PTC or NTC thermistor sensors.
Almost all factory temperature sensors fit this category. Do not wire the output of a 0-5V
temperature sensor (e.g. a pyro. module) to these channels, instead use an Analogue
Voltage Input.
Analogue Channel Specifications:
·Measurable Input Range 0-5V DC
·Input impedance 2.2M Ohm DC (4.7k Ohm AC).
·Maximum Input Voltage +/- 50 V
·Temperature Channel Pull-up Resister 1k Ohm to 5V
2.5 Digital Inputs
Digital Inputs are inputs that recognise either a high (+V) or low (GND) signal. Digital inputs
are typically set-up to monitor the position of manual switches or connected to sensors that
output a signal of variable frequency.
The following Digital Input Limitations Apply:
·Only Digital Inputs 1 to 6 can be used for frequency input (e.g. speed).
·Only Digital Inputs 1 to 4 can be used for Variable Valve Timing (VVT) cam position
input.
G4 ECU's have up to 10 Digital Inputs that can be configured for sensors/ switches such as:
·Vehicle Speed Sensor
·Antilag Switch
·Clutch Switch (for launch control and flat shifting)
·High / Low Boost Switch
·Water Spray Switch
·Dual Fuel / Ignition Map Switch

G4 Wiring and Installation Manual8
© 2009 Link
·Nitrous Oxide Switch
·Anti-theft Switch
·AC Request Switch
Digital Inputs have a software selectable pull-up resister that can be enabled when
measuring from ground switching devices (such as hall effect sensors).
Digital Input Specifications:
·Low Level Input < 1V
·High Level Input > 2 V
·Digital Input Pull-up Resister (if enabled) 4k7 Ohm to 12V
·Maximum input voltage +/- 50 V
2.6 Trigger Inputs
Trigger inputs are required from crank/cam angle sensor(s) (CAS) for the G4 ECU to
calculate the current engine speed and position.
G4 ECU's use on board digital trigger decoding to to determine engine position from the
given signals. Set-up of the trigger inputs is performed using PCLink Tuning Software.
Contact your nearest Link dealer for advice on wiring and set-up of trigger inputs if unsure.
Trigger 1 is used to determine crankshaft position. Trigger 2 is used to determine the
engines position in the firing order. In all cases Trigger 1 will need to be used. In many
cases Trigger 2 must also be used.
Engines with Variable Valve Timing may also require Digital Inputs be wired to cam shaft
position sensors.
Refer to the Trigger Wiring section for more information about trigger requirements for
different ignition/injection set-ups.
2.7 Summary
After reading this chapter you should be able to complete a list outlining the basic
configuration that will be used. It is important to write such a list as you will need to set up
each output in PCLink Tuning Software later on. An example of such a list is shown below.
A blank table to be filled out by the installer is given in the following chapter.
Configuration: 6 Cylinder, direct spark, sequential injection, turbocharged,
variable valve timing
Trigger 1
Crank Angle Sensor
Trigger 2
Cam Angle Sensor
Analogue Volt 1
MAP Sensor (Link 2.5 Bar)
Analogue Volt 2
Throttle Position (TPS)
Analogue Volt 3
After market Wide-band O2 Controller
Analogue Volt 4
Factory Narrow Band O2 (0-1V)
Analogue Volt 5 to 8
N/C
Analogue Temp Input 1
Engine Coolant Temperature
Analogue Temp Input 2
Inlet Air Temperature
Analogue Temp Input 3
Fuel Temperature

Choosing a Configuration 9
© 2009 Link
Configuration: 6 Cylinder, direct spark, sequential injection, turbocharged,
variable valve timing
Analogue Temp Input 4
N/C
+5V Out
TPS and MAP sensor power
+8V Out
Cam/Crank angle sensor power supply
Ignition 1
Igniter Channel 1 (Cylinder 1)
Ignition 2
Igniter Channel 2 (Cylinder 2)
Ignition 3
Igniter Channel 3 (Cylinder 3)
Ignition 4
Igniter Channel 4 (Cylinder 4)
Ignition 5
Igniter Channel 5 (Cylinder 5)
Ignition 6
Igniter Channel 6 (Cylinder 6)
Ignition 7
Fuel Pump Relay
Ignition 8
A/C Clutch Relay
Injection 1
Injector 1 (Cylinder 1)
Injection 2
Injector 2 (Cylinder 2)
Injection 3
Injector 3 (Cylinder 3)
Injection 4
Injector 4 (Cylinder 4)
Injection 5
Injector 5 (Cylinder 5)
Injection 6
Injector 6 (Cylinder 6)
Injection 7
Fuel Pump Speed Control 1
Injection 8
Fuel Pump Speed Control 2
Auxiliary Output 1
Idle Speed Control Solenoid (Close)
Auxiliary Output 2
Idle Speed Control Solenoid (Open)
Auxiliary Output 3
Tachometer
Auxiliary Output 4
Variable Valve Timing Solenoid
Auxiliary Output 5
Inter-cooler Water Spray
Auxiliary Output 6
Shift Light
Auxiliary Output 7
A/C Fan Relay
Auxiliary Output 8
Boost Control Solenoid
Digital Input 1
Vehicle Speed
Digital Input 2
Variable Valve Timing Cam Position Sensor
Digital Input 3
A/C Request Switch
Digital Input 4
I/C Spray Switch
Digital Input 5
Start Position Switch
Digital Input 6
Power Steer Switch
Digital Inputs 7 to 10
N/C

G4 Wiring and Installation Manual10
© 2009 Link
Example of usage of inputs and outputs
2.8 Installer IO Table
Fill out the following table to assist in installation. It will come in useful when configuring
inputs and outputs in PCLink Tuning Software. Shaded areas indicate I/O only available on
Xtreme ECU's.
Configuration: 6 Cylinder, direct spark, sequential injection, turbocharged
Trigger 1
Crank Angle Sensor
Reluctor,
Proximity, Optical
or Hall
Trigger 2
Analogue Temp Input 1
NTC Thermistor
sensors Only
Analogue Temp Input 2
Analogue Temp Input 3
Analogue Temp Input 4
Analogue Volt 1
0-5V Input from
sensor or external
controller
Analogue Volt 2
(Shared with DI4 on Storm)
Analogue Volt 3
Analogue Volt 4
Analogue Volt 5
(Internal MAP on Storm)
Analogue Volt 6
Analogue Volt 7
Analogue Volt 8
Analogue Volt 9
Analogue Volt 10
Analogue Volt 11
+5V Out
TPS and MAP sensor power
+5V Power OUT
+8V Out
Ignition 1
Use spare Ignition
channels for
switching type
Auxiliary Outputs
Ignition 2
Ignition 3
Ignition 4
Ignition 5
Ignition 6
Ignition 7
Ignition 8

Choosing a Configuration 11
© 2009 Link
Configuration: 6 Cylinder, direct spark, sequential injection, turbocharged
Injection 1
Wire Inj 1 to cyl
1, 2 to 2, 3to 3
etc...
Use spare
Injection channels
for switching type
Auxiliary Outputs
Injection 2
Injection 3
Injection 4
Injection 5
Injection 6
Injection 7
Injection 8
Auxiliary Output 1
High Frequency
PWM or VVT
Control.
Three Wire ISC
Solenoid must be
wired to Aux1 and
Aux2.
Auxiliary Output 2
Auxiliary Output 3
Auxiliary Output 4
Auxiliary Output 5
PWM less than 300
Hz or general
switching
functions.
ISC Stepper
Auxiliary Output 6
Auxiliary Output 7
Auxiliary Output 8
Auxiliary Output 9
(E-throttle Motor +)
E Throttle Motor or
GP Output
Auxiliary Output 10
(E-throttle Motor -)
Knock 1
Knock Sensors
Only
Knock 2
Digital Input 1
Frequency Input,
Switch Input or
VVT Position
Digital Input 2
Digital Input 3
Digital Input 4
(Shared with An Volt 2 on Storm)
Digital Input 5
Frequency Input
or Switch Input
Digital Input 6
Digital Input 7
Switch Input Only
Digital Input 8
Digital Input 9
Digital Input 10
Installer IO Table

G4 Wiring and Installation Manual12
© 2009 Link
3Component Installation Locations
The G4 Engine Management System and associated components may be installed in a
variety of locations but it is important to choose component locations in accordance with the
following guidelines.
3.1 ECU Location
The following items should be taken into account when choosing a location for the ECU:
1. The G4 ECU requires environmental protection for both physical and electrical factors
that may affect its performance. Normally this requires the device to be fitted inside
the vehicle cabin. This position avoids the high temperatures associated with the
engine bay and reduces the chances of the ECU getting wet. This position also offers
some physical separation between the ECU and ignition components that may cause
interference.
2. The main exception to this rule is where the engine is somewhat distant from the
driving position, such as a boat. In these cases the ECU should be mounted in close
proximity to the engine but NOT directly on, or next to, the engine (e.g. mounted just
outside the engine compartment). The idea here is to minimise the length of wiring
between the engine and the ECU while maintaining some physical distance to prevent
heat and interference. It is preferable to have short main wiring and a longer tuning
cable.
3. If water immersion or spray is likely (particularly for marine applications), additional
protection may be necessary. A sealed plastic container may be employed here.
4. Allow sufficient space at both ends of ECU for the main wiring harness and tuning
cables to be connected.
5. A mounting bracket is provided. Install the bracket on a flat surface and clip the ECU
into this bracket firmly. Use only the mounting bracket provided and DO NOT drill
holes in the case, as this will probably cause internal damage.
3.2 Ignition Component Placement
All components of the ignition system have the potential to radiate large amounts of
interference (electromagnetic radiation) that can wreak havoc on sensitive electronic
devices. Therefore it is essential that the ignition components are carefully placed and that
full suppression techniques are used. See the ignition wiring section for further details.
IMPORTANT
Never mount the igniter onto or next to the ECU
Always mount igniter(s) in the engine bay as close to the ignition coil(s) as possible. This
helps to minimize the length of high current wiring between the igniter(s) and coil(s). Avoid
areas of high temperature such as exhausts, turbochargers and radiators since the igniter
itself will generate heat at high power. If vibration levels will be excessively high, some form
of soft or rubber mounting is advisable to prevent component and wiring fatigue. Preferably
igniters should be mounted on the chassis rather than the engine to reduce vibration.

Component Installation Locations 13
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3.3 MAP Sensor Location
A Manifold Absolute Pressure (MAP) sensor is required for almost all applications. Storm
ECU's have an internal MAP sensor but can also be wired using an external MAP sensor.
Xtreme ECU's require the installation of an external MAP sensor. The MAP Sensor should
be installed in a location near the engine, but away from excessive heat, vibration and
moisture. It is not recommended to mount the MAP sensor directly on the engine. Refer to
Input Wiring section for more information on plumbing and wiring the MAP sensor.
Ideally the MAP sensor should be mounted higher than the inlet manifold so that moisture
will not condense in the MAP sensor hose.
4Storm Header Pinout
Viewed looking into ECU header (or wire side of loom connector)
* Pin can be used as either An Volt 2 or DI 4

G4 Wiring and Installation Manual14
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5 Xtreme Header Pinout
Viewed looking into ECU header (or wire side of loom connector)

Xtreme Header Pinout 15
© 2009 Link
6Power and Ground Wiring
Correct wiring of the power supplies is a very important part of the installation process. The
following sections describe wiring of power supplies to the ECU and also power supplies
from the ECU.
6.1 Power Supplies
The following diagram shows the recommended wiring arrangement for the power supplies.
The following key points are worthy of noting:
·The switch labelled ‘ignition switch’ is usually the key. The wire that is used to turn on
the main relay should be energised when the key is in the ‘ON’ position. Do not use a
source that provides power when the key is in the ACC position as these are typically
disconnected while the starter motor is being cranked.
·Each relay uses it’s own fuse. Ideally these should be located as close to the battery
as possible to minimise the length of unfused wiring.
·When the main relay is turned off all other relays will turn off. However, the high
current supplied by the other relays is NOT drawn through the main relay.

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Power and Ground Wiring
6.2 +14V In
Storm ECU's have one red wire that supplies power to the ECUs internal supplies.
Xtreme ECUs have two red power wires. The power wire in connector A is used to power
the ECUs internal supplies. The red +14V Aux 9/10 power wire in connector B is used to
power the Aux 9 and Aux 10 drivers. For non electronic throttle control applications both red
wires should be connected to a relay that provides power when the key is in the ‘ON’
position. BOTH +12V In wires must be connected at all times.
Although the ECU does not draw a large amount of current, the voltage applied to the ‘+14V
In’ wire must remain above 7 Volts at all times. This is especially important while the starter
motor is being cranked. A significant drop in voltage will result in the ECU undergoing a
reset that will stop the engine from running. As a result, it is important that the battery is in
good condition and suitable for the application. Also, make sure that all wiring to the battery
and associated terminals are clean and free from corrosion.
6.3 +14V Aux9/10
Note: this applies to Xtreme ECUs only.
The +14V Aux 9/10 wire provides an external power supply to the Aux 9 and Aux 10 driver
circuitry. This allows external disconnection of the supply to these drivers as a safety
measure when electronic throttle control is used. If electronic throttle control is not being
used connect this wire to the same power supply as the ECUs +14V In wire. If wiring with

Power and Ground Wiring 17
© 2009 Link
electronic throttle control, refer to the Electronic Throttle Control section of this manual.
This wire MUST be powered in order for the ECUs self diagnostics and the Aux 9 and
10 drivers to function properly.
6.4 Power Ground
These wires supply the high current earth for the output drives. Since these wire will carry
substantial currents, ensure they are well terminated to a clean earth point on the engine
block. It is also essential that there is a good clean connection between the engine block
and battery negative terminal.
IMPORTANT!
The Power Grounds MUST be run as SEPARATE wires. DO NOT be
tempted to join them together at the ECU and run as a single wire.
Also beware of poor earth points around the engine. Some manifolds
and other attaching parts may be rubber mounted and therefore have
poor earth bonding. A good rule of thumb is to use the engine
BLOCK or HEAD rather than attaching parts.
6.5 Sensor Ground
These wires are used to supply a ground reference for the sensors used by the G4 ECU. As
such, it is ESSENTIAL that these wires are used for all sensors that require a ground (e.g.
throttle position sensor, water temperature sensor, etc.). Failure to do this may result in
unstable sensor readings causing erratic ECU operation. Do NOT be tempted to ground
sensors to the engine block unless it is absolutely necessary (e.g. single wire sensor).
IMPORTANT!
Do NOT connect any green Sensor Ground Wires to the engine
block or other grounded point. This will cause current from other
devices to flow in the sensor ground wires and may result in unstable
sensor readings. Most sensors are isolated from ground so this is
usually not a problem. Pay particular attention to this point when
connecting external controllers.
6.6 +5V Out
This wire supplies a regulated and over current protected +5V to be used by sensors that
operate from a 5V supply. The most common example is a throttle position sensor (TPS)
and some manifold absolute pressure (MAP) sensors. Do NOT connect this wire to +12
volts or any other +5V supply.
6.7 +8V Out
This wire supplies a regulated +8V to be used for the Crank Angle Sensor (CAS) if optical or
hall sensors are being used. Do not use this wire to supply power for other devices.
Care must be taken as some optical and hall sensors are designed to use a 5V supply and
may be damaged if supplied with 8V. If a 5V supply is required then the '+5V Out' may be
used.

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6.8 ECU Hold Power Wiring
This wiring method is only used when an Idle Speed Control (ISC) Stepper motor is
wired. This wiring method allows the ECU and engine management system to remain
powered after the key has been switched off. This allows the ISC stepper motor to be reset
to the appropriate position for the next start up. The ECU will shut down the system when
reset is complete.
The other alternative is to reset the stepper motor at key-on, which can cause excessive
over-rev on start up or extended cranking periods.
This wiring method is shown in the following diagram.
How it works:
1. The ignition switch is turned on, powering the ECU through the external diode.
2. The ECU powers up and switches the ECU and Main Relays on.
3. All systems are powered through the relays now and run as normal.
4. When the ignition switch is turned off, the ECU senses this through its Digital Input.
5. The ECU resets the stepper motor to its default position, then shuts off the ECU and
Main relays when it is ready causing the system to power down.
The following items must be set-up in PCLink Tuning Software when using this wiring. This
should be done on the bench before installing the ECU to prevent damage to the diode as it
will be powering the system until ECU hold power is set up.
·The appropriate Digital Input must be configured as 'Ignition Switch'.
·The appropriate Auxiliary Output (or Ignition or Injection channel) must be configured
as 'ECU Hold Power'.
·The ISC Control 'Stepper Reset' function should be set to 'Key OFF'.
The correct operation of this wiring system can be tested by listening for a pause of a few
seconds between switching the key off and the ECU and Main relays switching off. The ISC
stepper motor may also be heard operating during this period.

Power and Ground Wiring 19
© 2009 Link
ECU Hold Power Wiring
7Input Signal Wiring
The following sections describe wiring of the various types of sensors used as inputs to the
G4 ECU.
7.1 Trigger Inputs
Trigger inputs are required for the G4 ECU to calculate engine speed as well as engine
position. In all but the most basic applications both Trigger 1 and Trigger 2 must be used.
These must be connected to crankshaft or camshaft position sensors to provide the required
information.
·Trigger 1 is used to determine crankshaft position.
·Trigger 2 is used to determine the engines position in the firing order (cam position).
Often called the sync signal.
·Digital Inputs may be required for Variable Valve Timing camshaft position sensors
(Refer to Digital Inputs Wiring for more information).
In applications using direct spark or sequential injection, Trigger 2 must always be driven
from a sensor on the camshaft a sensor using a trigger wheel that performs one revolution
for each 720 degree engine cycle.
The Trigger 1 and Trigger 2 cables each include two wires surrounded by a braided shield.
These have the following functions.