DIYPNP Documentation for 1995 – 1998 Nissan 240SX

The vehicle used for drawing up these application docs was a USDM 1996 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.

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 21.  The output of the “Input 1” circuit gets jumpered to pin 15 on the ConnectorBoard.  This pin 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.

• 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
      122	800
      194	200

  • 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
      68	2500
      122	800
      194	200

  • 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’.

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.

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.

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.