Nissan 240SX Information – Apexi S-AFC Installation Guide

This page provides detailed instructions for installing a Apex’i S-AFC in a 1991-1994 Nissan

Apex’i Super Air Fuel Controller: The Apex SAFC allows you to control
how much fuel will be delivered at certain rpms. This unit is mainly used
for people who have changed either there MAF, injectors or cams. For best
results this should be tuned using a dyno to insure proper settings. It provides many display
modes such as RPM and Throttle % as well as having three brightness settings
for optimal viewing.

  • Electrical Tape
  • 10mm Socket
  • Phillips Screwdriver
  • Wire Striper
  • Tap Connectors (Optional)


  • Disconnect Negative Battery Terminal

Remove 3 Screws on Passenger Side Kick Panel

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Remove Clear Cover That Snaps on Over The ECU Main Wiring Harness

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Remove The ECU Wiring Harness From The ECU by Using The 10mm Socket

I used a tap to connect my wires to my ECU, the tap allowed me to install
my afc without cutting any wires on the main harness for the ECU(see picture
of tap below).

Installation Instructions:

  • Proper Wire Range (19-26 Gauge)
  • Without cutting conductor, place unstriped run-wire inside run channel.
  • Be sure tap wire is evenly cut. Push lightly on wire until it is as far inside the opening as possible.
  • Use pliers to press down on connector cap until flush with the body if the connector.

NOTE: Wires should not be twisted after the connectors have been installed.

240SX S-AFC Installation Pictures

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Apex’i SAFC Wiring Harness Function KA24DE & S13 SR20DET ECU Wiring Harness
Red Power Black with White Stripe
Brown Ground Black
Black Ground Black
Green Engine Tachometer (RPM) Yellow with Red Stripe
Gray Throttle Signal White
Yellow Air Flow / Pressure Output White
White Air Flow / Pressure Input White
Blue Not Used Not Used
Pink Not Used Not Used
Orange Not Used Not Used

During Installation ECU Picture:

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Completed ECU Picture:

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Monitoring Choices:

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Analog View of RPM and Throttle:

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Analog View of RPM and Throttle with Graphic Equalizer:

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