DIYPNP Documentation for 1989 – 1990 S13 Nissan 240SX

1989 – 1990 Nissan 240SX USDM 2.4L KA24E MT

Test Vehicle Details:

The vehicle used for drawing up these application docs was a USDM 1989 Nissan 240SX KA24 with a manual transmission.  All factory electronics/ignition system components are in place and the factory wiring harness is in perfect condition.

Other notes:
All stock sensors were used.

---

What to buy:

Required:
1- DIYPNPJ64-K Kit.  This is the main DIYPNP Kit including the JAE style 64-pin connector and all components, case, etc.

Optional:
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 base maps 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.

---

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.

A/C Controls

In the Jumper Notes above we’ve included jumpers for A/C clutch and fan activation using the ‘Input 1’ circuit.  The Input for the AC system comes in from the A/C switch on ConnectorBoard pin 41.  The output of the “Input 1” circuit gets jumpered to both 9 and 11 on the ConnectorBoard.  These two pins will activate the A/C compressor clutch relay and the A/C condensor fan relay.  You will need to leave R14 out of this circuit or cut out R14 if you installed it.

---

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.

  • 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 with a bias resistor setting of 2490 ohms:

      Temperature    F	Resistance In Ohms
      68	2500
      194	250
      230	145

  • 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.

    • For the IAT, use the following table for the stock sensor with a bias resistor setting of 2490 ohms:

      Temperature    F	Resistance In Ohms
      14	9000
      68	2500
      122	820

  • 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 MAF

The DIYPNP allows you to disconnect the Mass Air Flow meter since it is not used in the fuel load calculation. When you remove the MAF, you will want to tape up the connector to protect it inside and out if you ever plan to re-use it.  The stock intake air temp sensor is not located inside the air meter so there are no wiring changes to be made.

Intake Air Temp Sensor: If you plan to install a turbo

The stock IAT sensor and location will not be adequate if you decide to run a turbo or supercharger.  For best results, you will want an air-tight seal with the sensor placed in the intercooler piping, after the intercooler and before the throttle body.  The temperature of the air as it enters the engine (not the turbo or supercharger) is what the ECU needs to know.  We offer an IAT kit (sensor and weld-in bung) for either steel or aluminum piping.

The MAF will need to be unplugged on cars that do not originally have an IAT sensor, and the white and orange wires used to send both the IAT signal and ground wires for the sensor back to the ECU through the factory wiring.  These wires come into the ECU on pins 16 and 17.  It does not matter in what order you connect the IAT wires to the MAF connector, or which of the terminals 16 or 17 you wire to IAT or SG (signal ground), the IAT sensor is not polarity specific.

---

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 athttps://www.msextra.com/ms2extra/.  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!