A'PEXi S-AFC Installation


Concept: Entry-level fuel computer designed to modify the air flow meter signalAlso can be used instead of the GCC for finer control of your VPC.

Characteristics: Easy to read VFD display, unparalleled list of functions

Comments: The second generation SUPER AFC follows the highly successful SUPER AFC in an upgraded package. The SUPER AFC is a vehicle specific fuel computer that modifies the air flow meter signal/ pressure sensor signal and allows the user to either richen or lean the fuel mixture. Adjustment ranges from +/- 50%. The Super AFC boasts an 8-point adjustable fuel curve with 500 RPM increment setting points. The Super AFC also allows the user to adjust fuel enrichment according to either LO/HI throttle positions. The AFC also cures the erratic idle problems associated with open atmosphere blow off valves on hot-wire air flow meter equipped vehicles. MONITOR MODE shows analog meter faces, Y graph display, Numerical display, Peak Hold, Replay Mode, 1 point/10 point and ghost map tracing. All correction factors are also displayed in percentages.


Here is what you will need:

- S-AFC wiring harness and head unit

- 10mm socket

- Wire crimpers

- Butt connectors and the supplied connectors


Lets get started!

1.Remove the negative battery cable.
2.Remove the wiring harness from the ECU. 
3.Refer to the ECU diagram.


  1. Splice the Green Wire (RPM) into 58.
  2. Splice the Gray Wire (Throttle) into 43.
  3. Cut wire 66 in half, leave yourself enough room to connect a wire to ECU harness.
  4. Connect the Yellow wire to the 66 wire connected TO the ECU harness.
  5. Connect the White wire to the 66 wire heading AWAY from the ECU harness.
  6. Splice the Brown wire (ground 1) into 69, close to the ecu.
  7. Splice the Black wire (ground 2) into 69 at least 1cm away from the Brown wire.
  8. Splice the Red wire (12V+) in to ECU wire 31.
  9. Pink and Orange wires are not used.

OK,  Now you have all of the wiring done, double check all of your connections, reconnect the wiring harness to your ECU.  Make sure all of those wires are still tight. Plug the harness into the S-AFC.  Reconnect your battery cable. Turn the ignition to the ON position.  The AFC should boot up and display A'PEXi, if screen did not light up, stop disconnect the battery and find out what went wrong.  Most likely it is power or ground problem (or a loose ecu harness.)


If the unit Powers On, follow these steps:

First start off by Resetting the AFC. Many have often complained that their AFC does not show full throttle(%100), regardless if it is brand new. Go under [etc.] and press NEXT~>. Confirm "YES" when prompted "Init. All?" and press NEXT again, Now turn the ignition OFF and then back ON, and the unit should now be reset and ready.

Next enter the following basic settings: 

-Go to [main] ~>[setting] ~> [3. TH-Point] ~> [Lo-94, Hi-95]

-Go to [main] ~>[etc.] ~> [1. Sensor Type] ~> [1. Hot-Wire]  ~>  [in-12, Out-12] ~>  [in-1, Out-1]

-Go to [main] ~>[etc.] ~> [2. Car Select] ~> [Cyl:6, Thr: UP]

-Go to [main] ~>[etc.] ~> [3. Graph scale] ~> [Ne = 7000rpm]

[Ne-POINT = 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000]

[Dec. -Air = NOT USED, unless you want to use it to compensate for venting your BOV to atmosphere]

Do not modify the low throttle settings.  While at low throttle (in closed loop mode) the ecu will counteract any changes made and over time your long term fuel map will be modified.  I recommend modifying your high throttle fuel curve on the dyno with an air/fuel ratio meter & egt gauge installed.  For maximum power, one probably wants to run an air to fuel ratio of between 11:1 (rich) and 12.5:1 (lean)  Do yourself a favor and pay a professional to tune it.  If you lean your engine out, things can melt.

Blue wire mod info:

This allows you to read Oxygen Sensor Voltage on the AFC display. On the wiring harness for the AFC the blue wire is not normally used. The blue wire is meant for the second Mass Air Flow Meter on a Nissan  300ZX. You will connect this wire to the O2 sensor wire right at the ECU. To read the O2 sensor voltage, scroll down to and select the "etc." menu. Select the "Sensor Check". Of the three readings, O2 voltage will be the middle one (#2).


If you are installing the VPC with the AFC, then install the AFC on the output wire of VPC