I hope this helps anyone in the future who has the A'PEXi VAFC and the Field VTEC harness in hopes of having a fully 'plug and play' device. Well, it is plug and play because you can take the Field Harness and VAFC out without affecting the current (i.e., stock) wiring at all. Beyond that, there is a bit of work to do in order to get the VAFC and Field's to work together. I spend about an hour looking at the Field Harness, diagram of pin locations on the ECU and in the VAFC manual in order to figure out what goes where.

For those that do not have the 2000 Helms supplement with the ECM/PCM Terminal Arrangement (pin locations), here is a link to a thread that contains them: https://honda-tech.com/zerothread?id=339871

The VAFC has 11 colored wires that need to be spliced into the harness. The VAFC manual clearly explains where everything should go, IF you were connecting it directly to the ECU/stock harness. I threw in the connector and pin locations too. Like this:

Red and Orange wires - Power Source - Connector B (25 pin) pin # 1
Black and Brown wires - Power Ground (brown MUST be closer to ecu) - Connector B pin #2
(Power Source and Power Ground also have pins at #9 and #10, respectively)
Green wire - RPM Signal - Ignition Control Module - Connector B pin 13
Gray wire - Throttle Signal - TPS/Throttle Position Sensor - Connector C (31 pin) pin #27
Blue wire - VTM Signal Input - VTEC Pressure Switch Signal - Connector C pin #10
Purple wire - VTEC Solenoid Input - (VTEC Solenoid Valve) - Connector B pin #12
Pink wire - VTEC Solenoid Output - (VTEC Solenoid Valve) - Connector B pin #12
White wire - Pressure Signal Input - MAP Sensor - Connector C pin #17
Yellow wire - Pressure Signal Output - MAP Sensor - Connector C pin #17

*Input wires connect to the wires that go towards the ECU.
*Output wires connect to the wires that head back to the stock harness.
(I know this must be obvious to most, but this is for we-todds like myself for future reference.)

This sounds all swell, right? Well, when you look at the Field VTEC Harness and compare the colored wires and their locations to the locations listed above, well, there are four colored wires in the wrong spots. The other seven wires are correct. Here's the Field Harness.



Put simply:

The two wires on Connector A (32 pin, top connector in the picture) won't be used. They are:
light blue, solid
green, solid

The other two wires that won't be used are at Connector C (blue connector), pin #23:
purple input wire
light blue, solid, output wire

ALSO .... on the Field Harness:
There is a black/red stripe wire that is connected to a white/green stripe wire in the VTM Signal location, Connector C #10. The BLACK wire is to be left unconnected. Only the white/green stripe wire is used, that leads to the ECU.

So, the final result is that you have to poke around for four black wires that have not been easily identified on the Field harness. Here is the final answer:

Field Harness color* VAFC Wire Color
Red ---------------------->Red and Orange (Power)
Connector B pin #2 ---->Black and Brown. BROWN MUST BE CLOSER TO ECU (Grounds)
Dark Blue (red stripes) >Pink (VTEC Solenoid Signal Input)
Yellow (red stripes) ---->Purple (VTEC Solenoid Signal Output)
Connector B pin #13 --->Green (RPM/ICM Signal)
Connector C #10**----->unused
White (green stripe) ---->Blue (VTM Signal Input)
Brown -------------------->White (Pressure/MAP Signal Input)
Orange ------------------->Yellow (Pressure/MAP Signal Output)
Connector C #27 -------->Gray (Throttle/TPS Signal)

*if not color, then pin location
**this black wire was described above. It is the only black wire that is connected to the white/green strip wire. It does not get connected to anything.

On the Field Harness: Green, both Light blue and Purple are to be disregarded as stated above.

I know this is long and cumbersome, but I am fairly certain that this information is all 100% correct. I checked through it 3-4 times before writing it out, then checked it again while typing. Please don't flame if there are errors, just send me an IM or post the correction. Maybe this can help simplify this process for those that want to use this harness in the future. It might be easier to simply splice and solder directly to the stock harness/ecu, but the 'plug and play' ability of the Field/VAFC contraption is enticing to me, hopefully others too.

Edits: Coherency
Edit 2: Thanks to Le for getting me the harness and forwarding some basic connecting info from Dropspeed. Thanks to Matt for answering a few questions I had to get me on the right track. Thanks to sgT for answering a few questions for me and discussing the capabilities of the vafc.
Edit 3: Final Note - I have not spliced the wires yet. I'll be doing this over the weekend.

Just in case you were wondering..... I'm talking about Field Harness VT-H7.





[Modified by Chris N, 3:11 PM 12/23/2002]

 

Great Info!

 

How did it go?

 

I haven't soldered yet. I just sat down with the ecu diagrams, vafc manual and field harness when I got home tonight and figured it all out. BTW, The Two Towers is most excellent.

My car is in the shop until after New Years, so all I can do is solder and wait for my car to come back.

 

some tips for soldering, try not to use too much solder, just where it is enough and splice and connect as short as possible. good luck.


[Modified by Art Vandeleigh, 10:03 AM 12/21/2002]

 

I made a copy of this for future reference. I plan on
getting me a VAFC for my R soon. I just wanted to say thanx
for your time to type all that "stuff"! MERRY HO-HO!!!

 

Thanks for the tip.

 

good deal man

I have already successfully put my together and soldered everything...it took me about a half an hour. You just have to use the pages as reference and it goes together reall easily.

Mine is for sale btw.

 

Thats a hell of a lot of info

god DAMN I hate electronics

Ryan, who has completely plug and play AEM standalone and does not need VAFC and Harnesses

 

its posts like this that make h-t

 

Chris N is definately a good guy sharing the info

but guys, remember installing a VAFC is not that difficult.

 

Chris.

At this point, I must interject and say that kenji's harness (obd2--->obd2) for a vafc is much easier to put together. He color-codes the wires to match up to those coming out of the vafc... simply put red and red or green and green together, etc, then solder and you're all set.

I've done mine and kengs, and they were very simple to do. Sounds like the fields unit is more of a PITA...

So send your business to kenji!

 

Question about the wiring. You say that the green wire on the Fields harness is not used. But checking the wiring at http://www.vtec.net/articles/view-ar...page_number=13 it indicates that the green is used for RPM which would connect to the green wire on the VAFC. Is the wire in the wrong location, or is there something else I am missing?


[Modified by VTECPWR, 11:59 AM 12/21/2002]

 

VAFC is hooked up differently than the fields

 

Right, I know they are hooked up differently. Maybe I am just a little slow. But both the Fields and the VAFC use the RPM signal and on the fields wiring harness this is a green wire which just happens to correspond to the green wire on the VAFC (RPM). So if both are Fields and VAFC need RPM why do Chris's instructions state to leave the green wire on the Fields unconnected? I am in the process of making all of the connections and this is one of the few remaining wires I have left.

Maybe another part of my confusion is that I am looking in the 1998 Service manual and just read in one of the links above that I need to use the 2000 Supplemental. Did not realize the info was going ot be different.

Chris thanks for the info it is a big help.


[Modified by VTECPWR, 5:30 PM 12/21/2002]

 

First of all, Soup is right. Connecting a VAFC is easy. Match up the wires and there you go. The problem arises when people believe that the Fields Harness is fully plug and play with the VAFC: it isn't. And it is damn confusing before you figure out that some of the Fields wires are the wrong wires.

Ken - If I had known that Kenji made an obd2-obd2 harness with the wires pre-marked for the VAFC, I would have bought that in a hearbeat. Somehow I missed that he did that. Maybe I just out to sell my harness and get one from Kenji.


[Modified by Chris N, 6:08 PM 12/21/2002]

 

According to the VAFC manual, the RPM signal comes from the wire directly to the right of the VTS/VTM signal on the ecu. This would be (according to the helms supplement) the ICM/Ignition Control Module.

Can anyone confirm this??

If this is the case, there is no need to use that green wire in question, because it is for engine speed pulse.

Well, hopefully this info will get used by someone at some point. Hopefully it is 100% correct, too. As for me, I might just get a harness from Kenji if I can sell the Field harness.

 

Chris, I agree completly about getting Kenji's harness had I known. For some reason I thought he wanted a lot more than he is asking (maybe his price has changed?). But I plan on finishing up with the wiring and installing the VAFC into the car tomorrow. Hopefully your wiring is correct. Thanks for all the help.

 

Need a little help. Was checking the fields wiring harness after I made 90% of the connections and finally noticed that I think I was sent the wrong one. The lable says VT-H6, I think it should be the VT-H4 but don't see any info on the H6? Can anyone confirm if I have the right or wrong harness?

TIA

 

My harness is VT-H7 - so i may have different wires that are colored. You may still be able to use the harness.


[Modified by Chris N, 4:14 PM 12/23/2002]

 

Edit: Pics moved to first post.

The harness in question, VT-H7, is shown up in my frist post. Take a look.... the green and blue wire on the uppermost connector are not used. The blue wire is connected to a location that is not listed on the 2000 supplement. (Must be something only used in the JDM ecu's.) The green wire is NEP - engine speed pulse. As sgT told me earlier,

This helps explain why all 11 wires that are color-coded are NOT used with the vafc. The purple/light blue wires that connect in the middle of the picture are the other two wires that I was referring to in the original post. They are grabbing the VSS signal.

So, you have to go and hunt for the other four wires in place of the two blues, green and purple that are no good when using with the apexi vafc.

I hope this helps to clarify what I was talking about above.


[Modified by Chris N, 3:09 PM 12/23/2002]

 

can someone tell me what a Field vt-h7 harness is?

 

I wouldn't even use solder. you can buy crimp connectors that wont create any resistance in the line, and heat shrink over top of them. We use them at bmw for everything including airbag wiring and bus systems. There also a lot faster to install!

 

do you realize you bumped a 8 year old thread to ask that question


lol i bet half the ***s on this board nowadays dont even know what a fields vtec controller is

 

I had a Fields VTEC controller in my first Type R. There was a lot of wire tapping but it worked good. It never really added any power though. It was interesting to adjust the changeover points for VTEC.