Nexus Plug-in ECU - Mazda RX-8 Series 1

Nexus Plug-in ECU - Mazda RX-8 Series 1



Congratulations on your purchase of a Nexus Plug-in ECU for a Mazda RX-8 Series 1. This vehicle-specific product allows you to seamlessly integrate a Nexus ECU into your vehicle without the complexities of wiring. With this hassle-free solution, you can jump straight into tuning. Nexus ECUs are at the forefront of engine management systems, featuring cutting-edge technology and innovative features. Designed for the next generation of automotive enthusiasts and professionals, this state-of-the-art ECU combines powerful engine control with a range of additional functionalities, making it a versatile and comprehensive solution for everything from everyday driving to high-performance racing. With full compatibility across a wide range of Haltech devices, it simplifies engine configuration and additional functionalities, all programmable through a single software platform.

Supported Models

• Mazda RX-8 Series 1 2003-2008, 13B-MSP Renesis 6-port (ADM, USDM, JDM, EUDM)
• Mazda RX-8 Series 1 2003-2008, 13B 4-port (JDM)
• Manual transmissions only
• Only CAN-based ABS modules are supported

What's in the box?

• Mada RX-8 Series 1 Plug-in ECU
• Air temperature + wideband expansion harness
• Air temperature sensor (1/8 NPT)
• Aluminum weld on fitting 1/8 NPT -27 TPI for air temp sensor
• Mounting brackets and hardware
• 2.5m vacuum hose and T-piece
• Haltech USB-C cable
• Quick start guide




Optional Accessories:

• HT-189002 - IO Expansion Harness 2.5m (8’)

• HT-010746 - LSU4.9 Wideband Hardware Pack




LED Behavior


ECU Specifications


Nexus Software Programmer (NSP)

Installing NSP

Haltech NSP is the software used for tuning and programming Nexus Plug-in ECUs. Follow these steps to install the Haltech NSP software:

1. Download the NSP installer - Go to the Haltech website Downloads section, and click on the download link for the NSP software.



2. Run the installer file - Once the download is complete, locate the downloaded file (usually in the ‘Downloads’ folder of your computer) and double-click on the file to run the Nexus Software Setup Wizard.


3. Launch Haltech NSP - Once the installation is complete, you can launch the Haltech NSP software from the Windows ‘Start’ menu or using the desktop shortcut that was created.



Going online with the ECU

With the NSP software open, connect the supplied Haltech USB cable between your laptop and the USB-C port on the front of the Nexus Plug-in ECU.



The USB connection will let the NSP software automatically recognize the ECU and activate the unit in low power mode. This allows you to either upload a basemap or create a new one through the setup wizard before installing the ECU into the vehicle. In low power mode, the ECU’s inputs and outputs are disabled, ensuring you to safely configure your vehicle setup prior to installing the unit and powering it up.


Setting up Wi-Fi communications

Wi-Fi communication is another method for connecting the Nexus Plug-in ECU to your laptop, serving as an alternative to a USB connection once the Wi-Fi module is enabled.

To set up your Wi-Fi connection follow these steps:

1. Open NSP and connect your Nexus Plug-in ECU using the provided USB-C cable.
2. Click on ‘Connections’ in the navigation tree and enable the Wi-Fi module.


3. Under ‘Connections’, select ‘Wi-Fi’ to set up your SSID and password. Note that your SSID must be at least 1 character long, and your password at least 8 characters.


4. Click ‘Apply’.
5. Power up the ECU using main power (ignition switch on), then go to your computer’s Network settings. Connect to your Nexus Plug-in ECU by selecting your chosen SSID and entering your password.



NOTE: The Wi-Fi antenna is internal on the Nexus Plug-in ECU. The unit must be powered by the main  power source for Wi-Fi communication. Up to two computers can connect to the ECU via Wi-Fi, and one via USB-C, at any given time. When the Wi-Fi module is disabled, it is completely inactive and held in an OFF state.

Haltech Connect App



The Haltech Connect App enables you to connect wirelessly to and interact with your Haltech Nexus Plug-in ECU via your smartphone or tablet. View real-time data from the ECU, set up basic gauges, clear DTCs, assign wiring, and adjust select parameters. Available for free on Google Play (Android) and the Apple App Store (iOS).



Nexus Plug-in ECU Setup Wizard



The NSP software, when used with a Nexus Plug-in ECU, features a comprehensive setup wizard designed to create a basemap tailored for your specific application.
The process begins with naming your vehicle, which creates a dedicated folder on your laptop for saving maps and datalog files. You also have the option to add a vehicle description—a useful feature for quickly identifying different map versions. Next, you select your vehicle and engine type from a list of Mazda RX-8 models from 2003 to 2008, followed by selecting the auxiliary harness you’re using. This allows the ECU to assign I/Os to specific sensors such as a wideband O2 sensor, pressure sensors, and more. The next few steps involve setting up engine-specific options, such as selecting between a 4-port or a 6-port, choosing the porting profile, and defining the injector for all different stages. After completing these steps, NSP presents a summary of your selections for confirmation, allowing any necessary adjustments before finalizing the setup. This thorough process ensures that the Nexus Plug-in ECU is optimally configured to start and run the engine with your own base tune.

Application Specific Notes


This Nexus Plug-in ECU is only compatible with the following vehicles:
• Mazda RX-8 Series 1 2003-2008, 13B-MSP Renesis 6-port (ADM, USDM, JDM, EUDM)
• Mazda RX-8 Series 1 2003-2008, 13B 4-port (JDM)
• Manual transmissions only


1. Wizard setup - Ensure that the ECU is correctly set up using the NSP software wizard, or that a correct map is uploaded to the ECU, before powering the unit through the vehicle.
Please note that the wizard setup or base map serves only as a starting point, and the ECU will require appropriate tuning. Haltech is not responsible for any engine damage resulting from the improper use of base maps.
2. Air Temperature Sensor - The factory air temperature sensor inside the MAF assembly can be used, or replaced with the one included in the kit.
3. Electronic Throttle and Pedal - The Electronic Throttle and Pedal (i.e. DBW) must be calibrated through the NSP software prior to starting the engine.
4. Forced Induction - This Nexus Plug-in ECU supports proper engine modifications to accommodate forced induction (e.g. boost control) using the available outputs in the auxiliary connector.
5. ABS Module/DSC - The ECU currently supports only the ADM, USDM, JDM, and two European versions of CAN addressing for the ABS module. K-line communications is not supported.



An unsupported ABS module will cause the ABS light to turn on, disable the ABS feature, and cause the speedometer and odometer to stop functioning, or result in a combination of these issues.
If this occurs, try selecting different options from the “Vehicle CAN Market” drop-down list found under Connections > CAN > Vehicle CAN System to see if one resolves the issue
After trying each option, the vehicle must be completely turned off, then turned back on and driven to give the module a chance to read vehicle speed before testing the next option.
6. DSC and Dyno Tuning - The “DSC OFF” button must be pressed for several seconds to disable DSC before operating the vehicle on a dyno. The “DSC OFF” indicator light will appear in the gauge cluster when the system is inactive. Press the button again to reactivate the DSC system
7. Wideband O2 - The factory front wideband O2 sensor (4-wire) is not supported. Instead, a Bosch LSU 4.9 or NTK sensor must be used via the auxiliary port connector.

8. MAP Sensor - The Air Flow Meter or MAF sensor signal is not used, and the onboard MAP sensor must be connected instead. A vacuum hose and T-piece are included and can be installed off the vacuum hose that runs to the VDI and SSV solenoids under the inlet manifold. Refer to the diagram below for the location and approximate routing of the vacuum hose.



ECU Pinout


Notes:

• The connector image shows the pin side of the ECU. Pins not listed in the table are not used by the ECU.

• Some injector pin functions are swapped internally depending on how the NSP wizard is set up (e.g. staged injection 6-port vs 4-port).

• Connector 3 is not present in the 4-port harness, but the ECU pins are still available for use as spare I/Os.

• DPO 9–23 functions are fixed and cannot be reassigned in NSP.






Auxiliary Connector

Nexus Plug-in ECUs are fitted with a 26-pin auxiliary connector that can be used to wire in sensors or devices not available in the vehicle from the factory.




The ECU also includes an expansion harness that plugs into the auxiliary connector and can be conveniently routed within the engine bay. The included expansion harness (HT-189000) provides a connector for a Haltech air temperature sensor, which can be used in place of the factory sensor—integrated into the air flow meter. A wideband O2 sensor plug is also included and is controlled directly by the ECU’s onboard wideband O2 controller, allowing direct connection to a wideband hardware pack. A set of spare pins is also provided for the 26-pin connector, enabling the addition of sensors such as fuel and oil pressure sensors, flex fuel sensors, or custom DPO functions (e.g. boost control) that can be configured in the NSP software.

To place pins into the auxiliary connector:
1. Push bottom tabs to unlock
2. Insert pin into harness side of connector
3. Push top tabs to lock




IO  Expansion Harnesses


In addition to the basic expansion harness included, Haltech offers an optional I/O expansion harness (sold separately) to conveniently support common sensor upgrades for your Nexus Plug-in ECU.




This expansion harness is terminated with connectors for sensors such as a Haltech wideband hardware pack, flex fuel composition sensor, oil pressure sensor, fuel pressure sensor, and air temperature sensor. It also includes spare pins for connecting additional outputs available on the 26-pin o.

ECU Installation

The factory RX-8 ECU is located in the engine bay, inside a protective enclosure near the right headlight. It features an air ducting system that channels fresh air from beside the radiator through the enclosure to help cool the ECU.



To install the Nexus RX-8 Plug-in ECU:
1. Remove the ECU enclosure cover by undoing the three cover screws and unclipping it from the enclosure base. The battery cover will also need to be removed for better access to some of the screws and clips.


2. Unplug the connectors from the factory ECU. Remove the three 10mm screws securing the ECU bracket, then remove the factory ECU, its mounting brackets, and the air duct as one assembly.

3. Unclip and separate the top and bottom halves of the air duct to remove the factory ECU. Then, place the bottom half of the air duct back into the ECU enclosure.

4. Install the new Nexus RX-8 Plug-in ECU and the supplied brackets into the ECU enclosure. Refer to the images shown on the right.
5. Reconnect the ECU plugs, the onboard MAP sensor vacuum hose, and the auxiliary harness. Then proceed with the initial ECU Setup Wizard.
6. Reinstall the top half of the air duct and the enclosure cover after completing setup and initial testing to confirm that everything is working correctly and any additional sensors are properly wired and functioning.


NOTE: When reinstalling the top half of the ECU enclosure, a semi-circle can be cut near the rubber seal at the back of the enclosure to route the vacuum hose and auxiliary harness through. Be careful not to crush the vacuum hose, as this could interfere with the MAP signal measured by the ECU. Seal the opening with silicone to ensure proper enclosure sealing.

Haltech CAN System

The Nexus Plug-in ECU is equipped with an onboard CAN connector for direct connection to a wide range of Haltech CAN expansion products.


Multiple CAN devices can be used simultaneously by linking them together using Haltech CAN cables and a Haltech CAN hub. Examples of Haltech CAN devices include the Haltech uC-10 display dash and the Haltech CAN keypad. The dash allows user-selected ECU or engine parameters to be displayed on a customizable screen, while the keypad enables you to scroll through multiple screens or control other functions managed by the ECU. Additionally, a Nexus IO16 can be added to expand input and output functionality via the Haltech CAN system, supplementing the onboard capabilities of the ECU. The diagram on the right illustrates an example of how to connect these Haltech CAN devices (sold separately).





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