DIYPNP Documentation for 1985-1989 Toyota MR2

1985-1989 Toyota MR2 (AW11) USDM 4AGE MT

Test Vehicle Details:

The vehicle used for drawing up these application docs was a 58K original mile USDM 1986 Toyota MR2 with 4AGE Motor.  All factory electronics/ignition system components are in place and the factory wiring harness is in perfect condition.  This car has been turbocharged, the injectors have been upgraded to Supra 440cc units, and other supporting mods have been made, also the TVIS System has been removed though we can still tell you how to control TVIS, no problems there.  We we will offer the startup map from our turbo car with large injectors, as well as an estimated map that’s been adjusted for the stock injectors.

Other notes:
Factory TVIS System Removed
440cc Supra Injectors
Stock ignition system using factory Toyota Ignitor
AFM Removed
Fuel pump jumpered on at the AFM
GM IAT Sensor wired in at AFM connector (coming into ECU on stock wiring)
Boost Control is enabled and tuned for this vehicle, you may either disable and/or tune properly for your vehicle.

What to buy:

1- DIYPNPN42-K Kit.  This is the main DIYPNP Kit including the Nippon Denso style 42-pin connector and all components, case, etc.

1- Tuning Cable  This is the same DB9 serial tuning cable used in other MegaSquirt applications.
1- USB Adapter  This is a DB9 serial to USB adapter.  The adapter is needed when the laptop or PC you are using does not have a built in DB9 serial port.
1- StimPower  This is a power supply that is normally sold to power a stimulator, but another use is it can be plugged directly into the DIYPNP mainboard to power the ECU directly, allowing you to load the basemaps and do limited testing on the ECU prior to installing the ECU in your vehicle.  It is particularly nice to be able to flash the firmware and load your configuration on the bench instead of in the vehicle, and allows for less risk of damaging something on the vehicle due to incorrect settings.
1- PNP_IAT-A or PNP_IAT-S AFM/MAF Delete kit. This is a simple kit with an IAT sensor, wire pigtail, crimp pins to poke into the AFM Connector to run the signal back to the ECU, and a steel or aluminum bung (hence the -A and -S in the part numbers).  Perfect for getting rid of a restrictive AFM/MAF with your DIYPNP install.

What tools you’ll need: Soldering Iron, Solder, maybe some desoldering braid in case you make a mistake.  Small phillips screwdriver.  That’s about it.

Startup Maps

Base Configuration .msq files to help you get your car fired up safely and quickly.  Ready to tune.

We’re including these maps prior to showing you how to jumper your DIYPNP up.  There’s a reason for that.  The base ignition settings contained in these maps should be loaded on your DIYPNP before you power your car up (with the key) with the DIYPNP installed.  This is to prevent damage to your ignition system in case the default settings are not correct for your vehicle. Note that you can power up the DIYPNP off the vehicle on a power supply connected to the power jack next to the DB15 connector.

So here’s our recommendation —  After you complete basic assembly, Power up your DIYPNP one of two ways.  Either plug a Stimulator Power Supply into the front panel of the box (the easiest way), or, start the Jumper Section below, but only connect the power and ground wires to start with.  That way you can plug the DIYPNP into your factory wiring harness and safely power it from your car.  The third option, if you’ve fully assembled and jumpered your DIYPNP already, is to unplug your coils from their power connectors before plugging the DIYPNP into your factory harness and powering it from there.

Then and only then, you can flash the firmware on your DIYPNP to the MS2/Extra firmware if you haven’t already, and then load the startup map provided to help you get your vehicle started.

Click Here to Download Startup Maps for this Vehicle

Once the vehicle is started, you will need to use the MS2/Extra manuals to set the base timing and begin to tune the vehicle!  This is critical!  Do not drive an untuned vehicle!

DIYPNP Jumper Configuration

This section will cover the standard, basic jumper configuration required to get the vehicle running using your DIYPNP.

Vehicle informationSystem Information
Market:USDMDIYPNP v1.1
Model:MR2Code Version:
Year:1986MS2/Extra 2.1.0
Edge Pin ConnectionsPull UpsIgnition Settings
MainAdapterConnectionResistanceVoltageSpark ModeBasic Trigger
IATA3ALEDTrigger Angle1
TPS SIGB11OPTO+1k ohm12vOddfire Angle
VR IN +IAC100 ohm5vUse Cam Signal
VR IN –High Current DriversIgnition Input CaptureFalling Edge
OPTO IN +B1OutputEnabledTo PinSpark OutputGoing High (Inverted)
OPTO IN –S1Number of CoilsSingle Coil
VR2 IN +S2Dwell typeStandard Dwell
IACS3Cranking Dwell4
TACH OUTS4Cranking Advance10
FUEL PUMP*Knock CircuitMaximum Dwell3.2
INJ1C9EnabledSensor +Sensor –Maximum Spark Duration0.7
INJ2C4Trigger wheel arrangement
12VA1I/O CircuitsTrigger wheel teeth
12VA8Input FromOut Pin ToPurposeMissing teeth
12VRelay 1Mainboard PA0ConnectorBoard C6TVIS ActivationTooth #1 angle
VREFB12Relay 2Wheel speed
5VBoostSecond trigger active on
SGA12Input 1and every rotation of
SGB14Input 2Notes
GNDC5Connect C10 to GND on Mainboard and GND on the Connectorboard

* See notes below on fuel pump.

GNDC7Misc Jumpers

Other Changes/Considerations

This section will cover changes that need to be made to the DIYPNP that go beyond the standard I/O jumpering, such as intake valve butterfly activation, on/off VVT activation, or other customizations to address the specific needs of a vehicle.

TVIS Activation

In the Jumper Notes above we’ve included a pair of jumpers for TVIS Activation using the ‘Relay 1’ circuit.  You’ll notice we suggested using PA0 on the mainboard to drive TVIS, and run the output from ‘Relay 1’ over to C6 on the ConnectorBoard to drive the TVIS Relay.  You can configure TVIS Activation in TunerStudio from the ‘Extended > Output Ports Settings’ Menu.  More information on configuration can be found in the MS2/Extra Documentation here.

Sensor Calibration

  • This vehicle does have a variable TPS.  You should calibrate it properly from TunerStudio in the ‘Tools’ menu.  Choose ‘Calibrate TPS’.

    • Make sure the engine is off, and the key is on.

    • With your foot off of the throttle, click the ‘Closed Throttle ADC Count – GET CURRENT’ Button.

    • Put the throttle to the floor.  With your foot fully depressing the throttle, click the ‘Full Throttle ADC Count – GET CURRENT’ Button.

    • Click Close.

  • Calibrate your CLT Sensor and IAT Sensor.  The bias resistor value is 2490 ohms.

    • Again from TunerStudio, click ‘Tools > Calibrate Thermistor Tables’.  Make sure ‘Coolant Temperature Sensor’ is selected at the top.

      • For the CLT, use the following table:

        Temperature    F / CResistance In Ohms
        -4 / -2015000
        68 / 202500
        140 / 60550
    • Enter these values, and click ‘Write to Controller’.

    • Now you’ll do the same for the IAT.  Select ‘Intake Temperature Sensor’ at the top in the drop down box.  (NOTE – If you are removing your MAF/AFM as a part of the DIYPNP installation process, do not recalibrate your IAT Sensor now)

      • For the IAT, use the following table:

        Temperature    F / CResistance In Ohms
        -4 / -2015000
        68 / 202500
        140 / 60550
    • Enter these values, and click ‘Write to Controller’.  Now click Close to Exit.

  • Finally, you should calibrate your O2 Sensor to the ECU.  To do this, click ‘Tools > Calibrate AFR Table’.

    • Choose your O2 Sensor from the list.  Choose Narrowband for the stock O2 Sensor.  Or select your wideband and the proper configuration of said wideband from the drop-down list.

    • Click ‘Write to Controller’.  Once finished writing, click ‘Close’.

Deleting the AFM

This is completely optional of course… but if you’d like to rid yourself of that pesky and restrictive Air Flow Meter you need to concern yourself with two things.  One, the stock IAT sensor is inside that housing.  Two, the stock AFM controls the Fuel Pump, as in the fuel pump will only run with the AFM flapper door is open (when the engine is starting or running and air is flowing through the flapper).  This allows the AFM to stop the fuel pump from running in the event then engine stops running, such as if you have an accident.  When you remove the AFM you need to restore this functionality.

IAT Sensor:

Simply wire a GM Open Element IAT Sensor into your factory wiring harness at the AFM connector.  You can poke wires into the AFM connector, or you can cut and splice.  Wire one lead of the GM Sensor to the Brown Wire at the AFM Connector, and the other lead of the GM Sensor to the Yellow wire at the AFM Connector.

Fuel Pump Control:

To control the fuel pump, you need to do two things.  You need to run a jumper wire between two wires at the AFM first.  The GRN/RED wire and the BLUE/RED Wire.  Connect these together.

Next, you need to add a jumper wire to the inside of your DIYPNP EMS.  Connect the FUEL PUMP hole (along the edge of the mainboard) to the A5 hole on the connectorboard.  Now your DIYPNP has control of your fuel pump.

If you previously installed your DIYPNP with the AFM in place, and calibrated the IAT Sensor for the MR2 Sensor, then you’ll need to recalibrate it now back to the GM IAT Sensor settings.  Go back to ‘Tools > Calibrate Thermistor Tables’.  Choose Intake Air Temp Sensor.  Choose ‘GM’ under ‘Common Sensor Defaults’.  Click Write to Controller and then click Close.

Read the Manuals, You are Responsible for your own results!

This Application Doc is intended to assist you in your DIYPNP DIY EFI Installation.  We’ve done a fair amount of research, and actually tested on a similar vehicle to help ensure we can provide the most accurate information possible to make your installation go as smoothly as possible. That said, there are certain things you could do incorrectly, or certain things you could change up, that could cause you to run into issues.  Our tech support department will be glad to assist you working through any issues you might have, please contact us and give us that opportunity and we should be able to work things out for you.

Startup Maps included/attached to this Application Doc is intended only to help you get your engine started so that you can properly tune your engine.  The map will be setup properly for a stock vehicle matching the year/make/model/trim in the ‘Test Vehicle Details’ section at the top of this page.  If you have made any changes to your wiring, your ignition system, or other related components, this map may not be ideal for your vehicle.  You will then need to check and confirm the appropriate settings and properly configure your DIYPNP EMS for your altered vehicle.  Some maps offered may be more completely tuned that others, some may be just setup enough to get the car to fire up and idle with a little help from the throttle.  That’s when the tuning begins.

In short — We’ve provided you with the building blocks for an incredible EMS.  You are however responsible for the implementation and your own successes or lack thereof, but rest assured that we’re here for you and we’re going to do everything in our power to make sure your project is a success.

For more information on configuring and tuning your DIYPNP EMS, and for information on adding and tuning custom MS2/Extra features, read up at  In fact, everyone implementing this system should read that manual from front to back if you really want to harness the power of the DIYPNP EMS.

We’d love to hear your feedback on our DIYPNP Application Docs.  Click Here to offer feedback/suggestions!