VAFC II Full Installation Info
 

Contrary to what people say. VAFC2 is the only one that will work on our 7th gen cars running D17 engines and vtec.One day I was doing a head swap into my DX and putting a EX head so i would have vtec capabilities and needed the wiring diagram for our cars.. as i was doing the install i notcied that not all the wires were being connected and used considering APEXI doesnt have the proper diagram for our cars... Which in turn is why i created this full install...With that in mind, while installing the unit i noticed that the manual that came with the thing does not have our car model listed but it does have our engine D17 listed... its listed as EU3 or EU4 in the book which says to use diagram H8-a... this is wrong.. it will get u the right install but not all the wires connected.. yes i know there is another thread that says its missing the VTM wire... but it is also missing another wire.. the TDC wire.. when installing the VAFC2 u should follow diagram H7-b which shows u were to connect the VTM wire and TDC wire.. but DO NOT connect the VTC CAM SIGNAL wire cause we do not have that on our cars... that wire on the ECU is for the Secondary 02 Sensor and not the VTC.. just tape it off and put it to the side cause its the only wire that wont be used.... the diagram also shows where to connect the VTM wire..Basically u are using a combination of diagram H8-a and H7-b to complete the install.. After creating this install guide GEARBOX has also gone back and redid his wiring to connect the rest of the wires.. He also has gone and made a modified version of Diagram H8-a which shows the rest of the connections.... My car runs fine and so does gearbox and hope this helps with everyones install. ~xproductionz

*Here is the updated wire diagram. I don't know what benefit the TDC will give, but it's better to just have it hooked up. Thanks for the info. ~gearbox

https://www.civicforums.com/forums/h...8177vafcii.jpg

The second piece of info you need to install this thing is the vafcII harness color code from the manual. This will show you how to match up the harness wires to the ecu wires. This diagram is ONLY for showing what each color means and whether the wire should be cut or spliced. The diagram above actually tells you where to wire them on the car.

Enjoy, ~gearbox.

Also you should know that the air/fuel ratio most likely cannot be adjusted because the ecu on 03-04 civics will adapt and counter any changes made with the vafcII over time. So I guess it's still useful to monitor engine functions like rpm, voltage, etc. This has yet to be proven with actual dyno results. ~gearbox

Also keep in mind that it hasnt been proven true yet that the ecus on 03-04 actually counter the changes.. but based on a 1 or 2 peoples experiences they say it does.. we will find out soon enough when somone puts the vafc into there car and get it dynoed and then gets it dynoed again like a year later or so. ~xproductionz

https://www.civicforums.com/forums/h...77DSC01783.jpg

INITIAL SETUP PROCEDURE--Very Important!!

Just after the install is done, you need to set certain functions in order for the vafcII to work with your car. As far as I know, these will work for a D17 1.7L SOHC VTEC engine on 2001-2004 civic EX.

If you started the car without performing this setup, you will need to reset the ecu and start over.

After the install, turn the car to the ON position but do not crank the engine. The vafcII display should now be active.

1) Sensor number IN 06 OUT 06
2) Number of cylinders = 4
3) Throttle position = arrow pointing north-east
4) Vtec number = 3
5) hold down accelerator for 10 secs, then release for 10 secs

Turn off the car and remove the key to save settings. It is now safe to start the car for the first time. There should be no check engine light at all.

DO NOT ever adjust any vafcII settings when the engine is running!! All changes including vtec engagement and fuel tuning must be made when the car is on, but engine is off, as described above.

It is strongly recommended that a dyno be used to measure and adjust the air/fuel ratio for your vehicle. The ideal ratio is 14.7:1 which is best for combustion and emissions.

As a general rule, our cars tend to run lean in the lower rpms and rich in the upper rpms, although this is not always true.

Have fun, ~gearbox.


Rule of thumb everyone... If u can... SOLDER the wires together cause based on exerperience i have had it where the connectors they provide come loose.. and it has happened to me on my 98 civic and actually blew my ecu... if u cant do it during the install now then u might want to put that on ur TO-DO-LIST for the future.. ~xproductionz

What does the TDC wire do? I better double check which wires I hooked up. I hooked up all of them from this wire diagram. What do I need to do differently?

...
 

You don't use the TDC wire, that's for Top Dead Center sensor I believe, and it's only used on i-VTEC engines...which we don't have...

Okay, that's what I thought.

we have the TDC on our cars.. its the wire right below the throttle signal.. pin #26 (green wire).. i put it on cause i didnt want to leave the wires hanging or unconnected.. now u can actually see the TDC on the screen now.. just wanted to have every wire connected except the VTC wire

What does TDC look like and what does it mean?

TDC means top dead center.. it tells the VAFC when it hits TDC... its in the manual.. if you still got it... if you look on the ECU its the green wire coming out.. pin #26 right underneath the throttle signal wire.... from ur VAFC it would be the light blue wire.. not the dark blue

Okay I'm gonna try it and then post a pic and make this thread a sticky.

thats cool.. i found all this out when i was doing the head swap on my dx and installing the vafc... had to go through a few wiring diagrams to figure it out... .. maybe the DIY head swap should be moved here and made into a sticky too.. lol :)

I tried it and now under sensor check there's a "dot" that blinks on and off. Is that what it's supposed to do? I'm guessing it is, since it didn't do that before. Thanks. I'll add it to the diagram.

yup.. thats whats its supposed to do... the shop told me that even though some people says its only for i-vtec that it helps the VAFC determine what position ur motor is thus making it easier to tune...i'll know for sure when i take my care to the dyno guys and ask them

Cool thanks again. One thing I noticed was the engine would make some growling nioses when I raised vtec, so maybe it needs this extra sensor input to match vtec engagement with tdc. Maybe. Let us know what happens.

yea.. did urs get louder too.. thats what mines did and it pulled slightly more when i was running on an abandoned back road.. but only a dyno will tell the story

Well the engine wasn't too happy sounding starting when vtec should have engaged but didn't. I just set it back to stock engagement since that felt like the best performance.

have u played with the vtec unmatched setting yet.. that might be why

Could be. I'm not experienced with that stuff. I need to find a place that will dynotune it. That's the only way to really know if there's more power being made.

trying to get my car dynoed... but it been booked till next week

will the vafc2 fix work the same for the VAFC1?

VAFC I does NOT work for our cars.

^^ ditto

i think there is some truth to this but also false... see there was a discussion on this thing too.. but see they say the ecu learns from the vafc adjustments and doenst work... my belief is that it does that only on the newer ecu.. 03+... see.. they say after a few weeks or months the ecu resets... i have a friend that has a turbo that got his car tuned and its gonna be well into a year that his car has been tuned... then recently he got his car dynoed again and the settings where pretty mucht the same... just a 1 point adjustment and he was set again...but he drives an 02 which makes me think that the 01-02 dont learn but the newer ones does

Good news then for me and my 02 vic. :) I guess I'll look into getting it tuned then.

yea.. and do a tranny swap too... haha.. j/k... have u ever thought about it though

What I want to know is if the ecu is so smart, why doesn't it add more fuel by itself when it sees more air from mods? It has all these sensors everywhere to calculate the a/f ratio, but it's not able to do this?

lol... i think the ecu has a threshold.. if it starts to see to much air i think then it might just throw a CEL instead of hassling with adding more fuel.. its a honda ecu.. they want u to bring the car in everytime it detects something weird... kinda funny though how honda makes so much restrictions on there cars yet they advertise it as if there cars were measnt to be racers.. remember the "HONDA NATION" commercials with all souped up cars in it

Damn.....I have a 03......

Look at the A/F ratio graph and hunt for 17.1 A/F below 2500rpm.....

didnt catch u on that one

i have the VAFC-II but i didn't connect the TDC center wire because I called a guy at Apexi who said not to connect it because it wasn't the i-vtec. i know that was already stated i'm just tellin yah what I got. Anywho i have my vtec engagement point set to 4000rpm and a + correction from 3200 - 4800rpm. I'm not in front of my settings so I don't know for sure. ... i kind forget... as soon as my car hits the 4000 rpm mark, you can definately feel it. now i'm wondering if i were to hook up the TDC wire would it help my situation or not? Like someone said, the tuners said to connect it so the ECU knew when the engine was top dead center. ...now i'm curious... any input?

I would hook it up anyway. It's obvious apexi doesn't know how their own product works. If you follow their instructions (and don't connect the vtm wire), you will get a check engine light and cause more problems.

Also on your settings. Raising the vtec engagement will make it feel more noticable, but low end power will suffer as well. After tuning, most cars will benefit more from leaving it at the stock 3k engagement. Also, our cars run rich from the factory. So most people who actually end up tuning their car with basic boltons end up subtracting fuel.

now if ur boosted like me then its makes a difference on when u set engagment time..as for fuel you'll end up adding more fuel when boosted but usually will lean out if not... but a friend of mines is leaned out till his vtec kicks in at 4500.. then i think it was like +2 or something like that.. dont know his exact numbers