Mazda 90-93 Miata – AMP-PNP-MM9093 – Installation

Jump to: Installation | Software | I/O Configuration | Jumper Matrix | Rear Options Connector

ECU Model / Vehicle Specific Installation Guide

Vehicle Fitment:

  • 1990-1993 Mazda Miata 1.6L - Manual Transmission

Please read all documentation before installing your AMP Plug-N-Play ECU and verify that you’ve followed all steps before starting your engine for the first time.

Physical Installation

All you need for a successful installation are basic hand tools. All parts removed during the following steps should be retained for reinstallation, as no factory parts will be discarded.

For a thorough and professional installation, you will need the following items:

  • Ratchet
  • 10mm Socket
  • Needle Nose Pliers
  • Zip Ties
  • Laptop with TunerStudio installed
  1. Disconnect the Negative Battery Cable
  2. Remove the ST SIGN Fuse
    The ST SIGN fuse is located under hood fuse box and NOT reinstalled after of your AMP Plug and Play ECU.
  3. Remove the Door Sill
    Begin by removing the passenger side door sill and pull back the carpet to expose the ECU cover panel at the front of the foot well.
  4. Remove the ECU Cover Panel
    Unbolt the ECU cover panel by removing the four nuts and a bolt at the top right. The same screws that hold the ECU cover panel in place hold the ECU to its mounts, so the ECU can now lift out.
  5. Remove the ECU Harness Fasteners
    There are small pop-in fastener holding the harness to the ECU frame.  Using a pair of needle nose pliers you can squeeze it the ends so they can be removed.
  6. Remove the ECU Connectors from Factory ECU
    There are two connectors that need to be unplugged from the factory ECU. These connectors can be difficult to release as they’re a fairly tight fit in the ECU socket.  Press the locking clips and pull on the connector to unseat them from the socket. Slightly rocking the connector back and forth helps with removal. 

  7. Route the vacuum line through the firewall
    The MAP sensor reference hose can be routed through an existing firewall grommet. Mazda happens to have provided a plug behind the windshield washer reservoir that’s about the perfect size for the MAP hose.
  8. Connect the vacuum line to manifold vacuum
    Route the vacuum hose neatly to the vacuum port on the side of the intake manifold. Trim the MAP hose to length and connect it to the nipple behind the throttle body as shown. If you have cruise control, you will need to cut the cruise control line and use the provided “Y” fitting to attach the MAP line.
  9. Connect the vacuum line to the ECU
    Under the dash, route the vacuum line neatly to the ECU and connect it to the reference port on the back of the enclosure. Make sure the hose is routed so it will not be pinched or trapped when the glove box is reinstalled.
  10. Wiring the Rear Options Connector

    This is the time to wire in your wideband along with completing any optional wiring you plan to use through the Rear Options Connector. This is the best time to wire additional sensors, inputs, outputs, speed inputs, or ignition upgrades, since the connector is easier to access before the ECU is mounted in the vehicle.

    Internal Wideband ECU Models
    If you selected the Internal Wideband ECU model, connect the provided wideband sensor cable to the rear options connector as instructed in the pinout section. This allows the wideband sensor to plug directly into the ECU without using a separate external wideband controller.

    No Wideband ECU Models / External Wideband Setups
    If you selected the No Wideband ECU model, or if you are using an external wideband controller, wire the external wideband controller signal to the appropriate rear options connector input.  Click Here: Wiring a Wideband Controller

    Additional Inputs and Outputs
    We also recommend wiring any other planned sensors or accessories at this time, including additional analog inputs, digital inputs, speed inputs, or outputs. This helps avoid removing or accessing the ECU later as your setup expands. Once your wiring is complete, plug the rear options connector into the ECU until it clicks into place and neatly secure the wiring. Refer to the Rear Options Connector section for pinout details and available functions.

  11. Connect the tuning cable
    Attach the serial cable to the AMP Plug-N-Play ECU.
  12. Connect the main ECU harness to the AMP ECU
    Attach the factory ECU connector to the AMP Plug-N-Play ECU using the reverse of the removal procedure. If the connector does not seat easily with the hasp, do not force it. Remove it, inspect alignment, and reseat as necessary.
  13. Route the Tuning Cable
    Neatly route the serial cable to a convenient location for future laptop access.
  14. Reinstall the ECU Cover Panel and Carpet
    Reinstall the ECU cover panel and the carpet using the reverse of the removal procedure.
  15. Reconnect the Negative Battery Cable

Software

Tuning Software Installation & Setup

Before starting the vehicle, install TunerStudio on your laptop and connect to your AMP Plug-N-Play ECU using the supplied tuning cable. Open TunerStudio, create a new project for the ECU. Once connected, confirm that TunerStudio shows the ECU as Online and that communication is working properly before making any changes.

View Tuning Software Installation & Setup Instructions →

Initial Configuration

Your AMP Plug-N-Play ECU includes a base tune that is configured for a stock application. If your vehicle has any changes from stock, you should review and update the tune BEFORE STARTING THE VEHICLE.

Examples of settings that may need to be reviewed or updated include:

  • Engine Size
  • Injector Size
  • Wideband Controller

Confirm that all required settings match the components installed on your vehicle before proceeding with startup and timing verification.

View Initial Configuration Instructions →

Verifying Base Timing

Now with your new ECU installed, you must verify that the timing commanded by the ECU matches the timing the engine is actually receiving. Improper ignition advance can cause engine damage if it is not checked.

  1. Connect a timing light to Cylinder #1
    Use caution, as secondary ignition voltage can be extremely high. Make sure the timing light leads are routed safely away from moving parts and hot engine components.
  2. Connect your laptop to the ECU and start the vehicle
    Open the tuning software (TunerStudio) and your vehicle’s project. Start the vehicle and confirm that the ECU shows Online.
  3. Set the ECU to fixed timing
    In TunerStudio, go to Ignition Settings > Ignition Options / Wheel Decoder. Under Fixed Advance, select Fixed Timing. Set Timing for Fixed Advance (degrees) to 10.0 degrees, then click Burn.               
  4. Check timing with the timing light
    Use the timing light to confirm that the engine is seeing 10 degrees of timing. If you have a single mark on your crank pulley, align it with the “10” on the indicator dial.  If you have two marks, align the left most mark will align with “10” on the indicator dial and the right mark will align with “T”.  If you have more timing, decrease the “Trigger Angle” (green box above). If you have less, increase this value.
  1. Set the ECU back to Use Table
    Once the timing is correct, change Fixed Advance back to Use Table, click Burn, and cycle ECU power by turning the vehicle off and back on.

Tuning

Congratulations, you have completed the physical installation, software setup, and initial configuration of your new AMP Plug-N-Play ECU. Your ECU is now ready, and you can begin tuning the vehicle.

Base Tune

Your AMP Plug-N-Play ECU is preloaded with a base tune for the specific ECU model and vehicle application it was built for. This provides a proper starting point for initial startup and tuning. If you ever need to restore the original base tune to the ECU, you can download it from our Firmware & Base Tunes page.

Removing the Mass Air Flow Meter

The preloaded base tune is configured for Speed Density, so the factory mass air flow sensor is not required. Removing the factory MAF and replacing it with a straight section of intake pipe can reduce intake restriction and may provide a small horsepower improvement.

The factory MAF also contains the factory intake air temperature sensor. If the MAF is removed, you must install a separate GM Open Element IAT Sensor so the ECU can continue to measure intake air temperature correctly.

Wiring the GM IAT Sensor

Connect the GM Open Element IAT Sensor to the third and fourth wires at the factory MAF connector, as shown in the diagram below. The IAT sensor is not polarity-sensitive, so either sensor wire can be connected to either of these two wires.

You may connect the sensor by installing terminals into the factory connector or by cutting and splicing the wiring. All connections should be properly insulated and protected from heat, moisture, and vibration. If the factory connector remains in place, fold the wiring neatly against the connector and seal the assembly with high-quality automotive electrical tape.

Calibrating the IAT Sensor

After installing the GM IAT sensor, turn the ignition key to the ON position without starting the engine. Connect to the ECU with TunerStudio, then complete the following steps:

  1. Go to Tools > Calibrate Thermistor Tables
  2. Select Air Temperature Sensor
  3. Select GM from the Common Sensor Values dropdown menu
  4. Leave the bias resistor value set to 2490.0 ohms
  5. Click Write to Controller

This updates the ECU calibration for the GM Open Element IAT Sensor.

IAT Sensor Placement

The IAT sensor must be installed where it can measure the temperature of the air entering the engine after any component that may heat or cool the intake air.

On a naturally aspirated application, install the sensor in the intake piping where it will accurately measure incoming air temperature.

On a turbocharged or supercharged application, install the sensor after the compressor and intercooler, as close to the throttle body as practical. This allows the ECU to measure the actual air temperature entering the engine after the air has been heated by the compressor and cooled by the intercooler.

Important: Do not position the IAT sensor where it only measures ambient engine-bay temperature. Accurate post-intercooler air temperature is required for proper fuel and ignition calculations.

Installing an Aftermarket Variable TPS

The 1990-1993 Miata was not originally equipped with a variable throttle position sensor. A variable TPS is not required for most ECU functions, but it can provide additional tuning options and may make throttle-based acceleration enrichment easier to configure.

The AMP Plug-N-Play ECU allows you to add a variable TPS using the factory wiring harness. This is an optional modification and will require wiring changes because a direct plug-in TPS with the correct factory connector and pinout is not available.

Identifying the TPS Terminals

If the TPS terminals are not labeled, use an ohmmeter or multimeter to identify the 5V reference, sensor ground, and signal terminals. Measure the resistance between each pair of terminals while slowly opening and closing the throttle:

  • The resistance between the 5V reference and sensor ground terminals will remain nearly constant.
  • The resistance between sensor ground and signal will be low with the throttle closed and increase as the throttle opens.
  • The resistance between the 5V reference and signal will be high with the throttle closed and decrease as the throttle opens.

Once the terminals have been identified, connect the TPS to the factory wiring according to the pinout shown above. Properly splice, insulate, and secure all wiring.

Enable the Variable TPS Input

After the TPS has been installed and wired, remove the top cover of the ECU by removing the (4) Phillips screws. Follow the Jumper Matrix for the location of the jumper that needs to be applied.

Calibrate the TPS

Turn the ignition key to the ON position without starting the engine. Connect to the ECU with TunerStudio, then complete the following steps:

  1. Go to Tools > Calibrate TPS.
  2. With your foot completely off the accelerator, click Get Current next to Closed Throttle ADC Count.
  3. Press and hold the accelerator pedal fully open, then click Get Current next to Full Throttle ADC Count.
  4. Confirm that the full-throttle value is at least 200 counts higher than the closed-throttle value.
  5. Click Accept to save the calibration to the ECU.

The possible ADC range is from 0 to 1023, although most TPS sensors will not use the entire range. A closed-throttle reading between approximately 0 and 300 and a full-throttle reading between approximately 700 and 1000 is common.

If the full-throttle reading is lower than the closed-throttle reading, swap the 5V reference and sensor ground wires, then repeat the calibration.

I/O Configuration

Below is a breakdown of the I/O usage for your AMP Plug-N-Play ECU. This identifies the default pin assignments for your specific vehicle, allowing you to see which inputs and outputs are already being used for factory functions and why those pins may not be available for use in the tune.

ECU Internal Jumper Matrix

Below is a diagram and overview of the available internal jumpers and their functions. To access the jumpers, remove the top (4) screws from either side of the ECU End Plates.

JP4: Variable TPS Enable (1990-1993 Miata Only)

This jumper is only used on applications where a variable throttle position sensor (TPS) has been installed. Install this jumper on 1990-1993 Miatas that have been modified with a TPS that provides a variable signal.

Default Setting: Not Jumpered

JP7: AFM Signal Selection

This jumper allows the factory AFM signal wire to be repurposed for boost control. When installed, the boost control output is routed to High Current Out 1 (HC1) on the AMP Plug-N-Play ECU.

Default Setting: Not Jumpered

JP8: Cooling Fan Control (1.6L Miata Only)

This jumper is only used when you want the AMP Plug-N-Play ECU to control the main cooling fan. By default, the jumper is left off and the factory thermoswitch on the thermostat housing controls when the cooling fan turns on and off.

Default Setting: Not Jumpered

Rear Options Connector

Your ECU includes a bag containing (2) connector housings and (2) banded sets of pre-terminated wires. One set of wires is intended for the larger openings in the connector, and the other set is intended for the smaller openings. Reference the pinout below for available rear options connector functions and wiring locations.

Important: The pinout diagram below is shown from the back of the connector.

Printable Copy of Rear Options Connector