How to Install a VAFCII in a RSX

How to Install a VAFCII in a RSX


Piggyback computers as a whole have run a long gambit in the history of forced induction and import applications, and while they are mostly shunned in today’s market there was a time when these simple computers were loved. Back when ROM flashes and standalone ECU’s were much more expensive, and consumers had no choice but to resort to piggybacks most enthusiasts went through severe trial and error periods using and testing the various piggyback computers.

While it’s definitely not a time you could recommend a piggyback to just anyone, it is still more than useful as a tuning device so long as you don’t ask too much of it. Today we’ll be installing a VAFCII into a 2001 RSX. This VAFCII was designed for I-VTEC applications, including the 7th generation Civics and D17 engines.

How to Install a VAFCII is an easy task and straightforward procedure, and can be installed by any average mechanic in less than a few hours.

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Tools you will need

  • Electrical Tape
  • Pliers
  • Wire strippers
  • Wire clips or Solder iron

First, look over your VAFC booklet and wiring diagram. The RSX pinouts are shown here, please make note of the year ranges and plan accordingly.



We have also attached a copy of the Apexi documentation so that you can get a clear grasp of what you are connecting, and how the crucial power and ground wires should be situated.



The appropriate VAFC wires and ECU pinouts are as follows :

Red Power Yellow / Black
Brown ( Secondary Ground ) Black (ground)
Black ( Primary Ground ) Black (ground)
Gray ( Throttle Signal ) Red / black
Orange ( TDC Signal ) Blue / White
Light Blue ( VTC Cam Signal ) Green
Yellow ( ECU Side of pressure signal output ) Green / Red
White ( Harness Side of pressure signal output ) Greed / Red
Purple ( ECU Side of VTEC Solenoid signal output ) Green / Yellow
Pink ( Harness side of VTEC Solenoid Signal output ) Green / Yellow
Green ( RPM ) Blue
Blue ( Unused in this install ) N/A

First, pull back the passenger side seat as far back as it will go to allow you the space to operate under your dash.  Then we will pull back the carpet to expose the ECU cover so that we can gain access to the ecu and floorpan.


You will see 2 pin buttons, pull those push pins out and pull off the cover to expose the ecu.



Take the time to disconnect your negative terminal on your battery, before undoing the ecu clips.You will of course want to locate you radio code before doing this if you still have the factory stereo.



First, cut the Green / Red wire on your ECU that is the pressure signal output for your RSX. Connect the Yellow wire to the ECU side of the pressure signal output, and the white wire to the harness side of the pressure signal output.



Now connect the 2 VAFCII power wires ( red ) to the Yellow / Black ECU wire. Then tap / solder your ground wires securely to your ECU harness, seperating the black and brown wires approximately 1 inch apart from each other. ** BE SURE TO INSTALL THE BROWN WIRE TO THE ECU SIDE FROM THE BLACK WIRE**



Connect the Gray VAFC Throttle wire to the Red/Black ECU wire.





Connect the Light Blue ( VTEC cam Signal ) wire to the Green ECU wire



Connect the Orange ( TDC Wire ) to the Blue / White ECU Wire.



Zip everything back up and you have now completed our How to Install a VAFCII writeup. You are now ready to tune and race your RSX with your VAFC!!!!

More How To’s :

Setting up your VAFCII

Tuning your VAFCII