DIYPNP Documentation for 1991 – 1994 Nissan Sentra

The vehicle used for drawing up these application docs was a USDM 1994 Nissan Sentra GA16 with a manual transmission.  All factory electronics/ignition system components are in place and the factory wiring harness is in perfect condition.

Other notes:
GM open element IAT added.

Radiator Fan

In the Jumper Notes above we’ve included a jumper for radiator fan activation using the ‘WLED’ circuit.  Run the output from ‘WLED’ over to 10 on the ConnectorBoard to drive the fan relay.  You can configure the fan activation in TunerStudio from the ‘Extended > Output Ports Settings’ Menu. 

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.

Intake Air Temperature Sensor

This Sentra did not have an intake air temp sensor.  The MAF will need to be unplugged 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.

• 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
      94	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 (remember we used a GM sensor since there was no stock IAT sensor) with a bias resistor setting of 2490 ohms:

      Temperature    F	Resistance In Ohms
      48	7000
      87	1930
      146	560

  • 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. When you remove the MAF, you will need to install a GM style intake air temperature sensor in your intake. This sensor connects to the third and forth pins on the MAF connector.  IAT sensors have no polarity, so it does not matter which wire you connect to which pin.

IAT Sensor:

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

Pictures for example only (not the actual Nissan connector):

The wires should then be folded down over the edge of the MAF connector, and the whole assembly firmly and cleanly wrapped in high quality electrical tape sealing it up. 3M makes some good stuff that can handle the temps found in engine bays– read the specs.

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.