Link G4X plug-in Mazda Familia GTX/GTR, MX5 Miata

Please Note: ECUs available on back-order usually ship within 2-3 working days

$ 2,064.25$ 2,205.00

Incl. Tax (NZ Customers)

Excl. Tax (International Customers)

Link G4X plug-in Mazda Familia GTX/GTR, MX5 Miata


Link Part #MX5X (SKU: 212-4000)


The Link G4X range of engine management systems builds upon the previous G4+ ECUs by featuring an all new micro-processor, an upgraded communications chip and expanded data logging. These improvements allow for a more responsive and accurate tune, much faster download speeds and far greater internal data logging capacity.


The Link G4X range of engine management systems are well known for delivering class-leading performance without sacrificing factory levels of drivability. The G4X plug-in ECUs are designed to be the most complete plug-in solution yet.


This Mazda plug-in ECU will save you time and money as it will plug straight into the vehicle’s original wiring loom without the need for messy adapter harnesses. It replaces the original circuit board inside the factory ECU enclosure and mounts using the factory brackets.


This Link G4X Mazda MX5/Miata/GTX/GTR plug-in ECU is suitable for the models listed below:


  • Mazda MX5 / Miata 1989-97 1600cc B6-ZE versions (NA chassis series)
  • Mazda 323 / Familia GTX and GTR 1989-94 models with 1800cc BP-T engine


Note: For MX-5 / Miata models, this G4X plug-in ECU can also be used used on early 1800cc models that have a 2-plug ECU. This typically includes the first generation (NA) cars. Models with 3-plug ECU’s, which are typically second generation (NB) cars, are NOT supported regardless of whether they are 1600cc or 1800cc models.


Once the installation is complete, the Link G4X allows a good tuner to achieve an optimal state of tune to get the most out of any combination of modifications.


All Link G4X plug-in ECUs come with a base map. While these maps are designed to help save time for you and your tuner, it is essential that these are used simply as a starting point for further tuning.


The engine can easily be converted to speed density by removing the air flow meter and instead using a suitable MAP and air temperature sensor.  Likewise, this ECU can also be setup to control boost electronically with in-cabin adjustment. This eliminates the need to purchase a separate electronic boost control system.


The vehicle’s original sensors & actuators are used except for the following exceptions:

  • MAP sensor – The MX5/Miata/Familia G4X plug-in is provided with an on board 4.0 Bar MAP sensor. This is suitable for up to 300kpa (44psi) boost. The on board & external MAP sensors are also suitable for naturally aspirated applications. The airflow sensor is not required.
  • Inlet Air Temp Sensor (IAT) – For naturally aspirated applications the factory IAT sensor is supported and is suitable to use. For forced induction a suitable IAT sensor should be fitted just prior to the throttle body (these are available from NZEFI). This should then be connected to the expansion connector of the ECU. Alternatively options exist for modifying the factory loom to use existing wires for the IAT sensor (contact NZEFI for details on this).
  • Electronic Boost Control – In the case of the Familia GTX/GTR the factory boost solenoid wiring is used, however an appropriate boost solenoid must be used (this is available from NZEFI). For MX5/Miatas that have been turbocharged the same valve is used and NZEFI can assist with wiring details.
  •  Injectors – The G4X plug in is NOT designed to be used with low impedance injectors. All of the Mazda models this G4X plug is designed for use high impedance injectors so no changes are necessary. However if low impedance aftermarket injectors have been fitted then the correct ballast resistors MUST be fitted. These are available from NZEFI
  • Throttle Position Sensor (TPS) – Some of the MX5/Miata 1600cc models do not have a factory fitted TPS. A suitable TPS needs to be fitted and connected to the expansion connector on the ECU (contact NZEFI for assistance with this). This is required such functions as acceleration enrichment, idle speed control and motorsport features. The 1800cc MX5/Miata & Familia GTX/GTR have factory fitted TPS that are supported.
  • Fuel Pump Wiring– Some models may require modification to the fuel pump wiring, NZEFI can advise what is required.


Extra sensor inputs

The expansion connectors on the Link G4X board is provided to allow the easy connection of additional ECU inputs. The two expansion connectors on this particular plug-in model provides the following:

  • 2 x 5V Supply
  • 2 sensor grounds
  • 4 digital inputs
  • 4 analogue voltage inputs
  • 2 analogue temperature inputs


These may be used for functions such as driver adjustable boost control, switchable fuel/ignition maps, wideband lambda input, external MAP sensor, IAT sensor, fuel pressure and oil temp/pressure.



Any redundant outputs may be reconfigured & used for alternative uses. Examples include, shift light, water injection, NOS control etc.



In addition to the ECU which can be purchased separately, we also offer the following packages:

Basic ECU Package:

Turbo ECU Package:

Please select the appropriate package from the drop down menu.

Additional information

Weight 800 g

Part Type



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