Thread: Help wiring VVL w/ VAFC (Updated with instructions)

I am going to be wiring up my VVL solenoids soon and I have a couple of questions. I have searched and read hundreds of posts on many different forums but have yet to find the info that I need. Any help would be greatly appreciated!!

I am going to be using an Apex-i VAFC to switch the VVL. Yes, I know there are better options such as Greddy MSS, MSD 8969 and Granatelli. I bought this unit back in February before I bought my engine, on the advice of a B15VE guy. It is already bought and paid for. I will not be using the A/F functions as it runs off of a MAP sensor, I am only using this for VVL activation!

I have the wiring diagram and I am pretty much ready to go but have a couple of questions:

1) In the wiring diagram it says to ground the VAFC brown and black wires to ECU ground with the brown wire spliced closer to the ECU than the black wire. "Failure to do so may result in engine damage". Yet I have read that others have just grounded these wires together to the engine block. Is this safe and why would Apex-i suggest the brown wire closer to the ECU?

If I can avoid splicing the Engine harness here and just use a regular ground, that would be preferable.

2) Where is the best place to splice into the Harness for the RPM and necessary signals. Inside of the "Black box" that houses the ECU in the firewall or just "wherever"? I would think protecting the connection inside of the ECU box would be best??

3) For the Red/Orange wires from the VAFC it says to use IG Power, but I plan to use Pin # 43 "Ignition" as it receives constant 12V from the battery. Or is it just better to use the battery?? I would think so...

4) And finally I've read that the VAFC has a built in relay so that the 12V power isn't constant to the solenoids. Is this true? Anybody know? I couldn't find anything about this in the manual.

Thanks in advance for any help or advice given!

I have a vafc I wired it to stereo the whole ecu ground is for hondas since they use the ecu vtec signal and then the green wire on the vafc goes to the selonoid mine was working fine untill I threw in the sr16ve ecu stopped working weird..... the vafc turns on but no vvl but if I throw in the stock de ecu it works any one have any ideas I have my rpm signal connected to pin 3 are sr16ve pins diffrent other than the extra vvl pins?

I have the vafc2 and the wire for vvl engade is pink a think green is rpm signal

Yeah your right I I can't remember the color of the wire that goes to the ecu on the hondas vtec related

Yes sir you are right. Pink is Vtec solenoid signal output and green is RPM.

I still wonder about the ECU ground though. Even if I ground the unit to the engine or the chassis, maybe it would be wise to keep the brown ground wire shorter than the black and closer to the VAFC so it receives the power signal first? Who knows.

How did you guys ground your units?

Hey bro when I wired mine it went to a yellow cable on the ecu every one says to wire to blue orange wire that goes to the tach where can I find it is off the main harness by ecu or behind the cluster only thanks

^ Yellow on Nissan OBD2 16-bit and OBD2 32-bit is TPS (Throttle position sensor). It is probably the same for OBD1 as well as Nissan usually keeps their wire colours the same or pretty close. Yes, the blue with orange stripe (L/OR) wire is for tachometer/RPM signal. It can be found off the back of the ECU here:

OBD1 - pin #2 on ECU
OBD2 - pin #3 on ECU (16-bit ECU/early OBD2)
OBD2 - pin #32 on ECU (32-bit ECU)

You can use the RPM signal behind the dash as well, or you can use the RPM signal off your distributor. I think I am going to use this so I don't have to cut the main harness or pull out the dash cluster.

I am not sure if the 16VE ECU has the same wire colours but I would think so.

So I figured I would update the thread for those that care and for future help for someone else.

I wired up my VVL last night and for the first time ever I am a member of the VVL club. I set it to engage at 4800 RPM on the Low-->High switch and disengage at 4600 RPM on the High-->Low switch on the way back down. I may change the disengage point to 4500 or even 4400 to stay in VVL longer when I up-shift because of my low red-line. This problem will be solved when the new ECU goes in and the Rev limiter gets raised a bit!

So, when the VVL "pops" I smile from ear to ear! It is louder than I expected but I don't mind at all.

Here is what I did: (Wire Apex-i VAFC into B15 '01 Sentra with SR20DE ECU)

I decided to do just as the VAFC manual suggested and wire accordingly.

I used the wires coming out of the back of the ECU. I did not splice or cut the engine harness. I did a "tap and wrap". I cut into the wire cover, pulled it to the side a 1/4" or so and then peeled the necessary VAFC wire cover back an inch or so and wrapped it tightly around the proper ECU wire. I know lots of people will say that you have to solder, and I may in the future but it was getting late and dark. Plus, this method is more than good enough to carry a signal from wire to wire. You just have to make sure you wrap tightly and tape and heat shrink very well to keep continuity between the wires and avoid problems. Also, with this method you avoid cutting up your harness and if you decide to uninstall the VAFC at any point in time, all you have to do is remove the tape and VAFC wire, slide the cover back over to cover the bare ECU wires and your wires are almost back to their original specs.

** The below method worked for me. I cannot guarantee your success as I am not doing your work! If you are not comfortable working with wires and your car's computer, please get someone who is knowledgeable/experienced to help you out. It is not a difficult process, but make sure you give yourself enough time to complete the steps without rushing. It should take you 1-2 hours from start to finish depending on your skills. Good Luck! **


Notes/Info:

Before starting make sure you have all of the necessary tools such as Electrical tape, heat shrink tubing, 14-18 AWG wire, wire cutter/strippers, socket set, butt connectors and a ring terminal for grounding the solenoids to the engine block. Also, make sure you have the proper instructions for your VVL controller and a pin-out diagram for the back of your ECU, so you know which pin and wire controls what function. It will also be helpful to look in your FSM and see which colour the wires are so you don't get confused. The wires are small and packed very tightly in a s mall space so having thr proper pin location and wire colour will be helpful. Here is a wire colour diagram for my car, it may match other ECU's as well, but you should ALWAYS check.

This shows a code for the color of the wire.
B = Black
W = White
R = Red
G = Green
L = Blue
Y = Yellow
LG = Light Green
BR = Brown
OR = Orange
P = Pink
PU = Purple
GY = Gray
SB = Sky Blue
CH = Dark Brown
DG = Dark Green
When the wire color is striped, the base color is given first, followed by the stripe color as shown below:
Example: L/W = Blue with White Stripe

Pin-out diagram: Follow the link below for a B15 pin-out.

Nissan, 240sx, nissan sentra, nissan sentra se-r, G20, nissan skyline gtr, nissan silvia, S13


Steps:

1) Dis-connect negative terminal on car battery for safety.

2) Remove bolt from FSTB (Front Strut Tower Brace) on passenger side and raise the brace upwards, leaving the other side attached. This will make it possible to remove the ECU from the firewall.

3) Remove the screws that secure the ECU into the firewall and pull out ECU.

4) Remover ECU cover screws and pull the plastic cover off.

5) Run the wire for your VAFC through the glove box of your car through the fire-wall and into the engine bay. You can leave the VAFC unit in your glove-box permanently so you can adjust it later.

6) Unscrew the ECU from the box, slide the plastic wire cover over to the left and then pull the harness plug (carefully) out of the ECU. You now have better access to the wires and more room to work.

7) Locate the tachometer signal wire (RPM) at pin #32, blue wire w/ orange stripe, use wire-strippers and with the 22 AWG setting and puncture the wire cover a few inches away from the ECU. Pull the wire cover to the side. Take the green VAFC wire, strip back 1/2 to 1 inch of wire cover and then tightly wrap the green wire around the ECU RPM wire. Use a small piece of electrical tape to secure and cover the connection.

8) Find a 12V power source wire. I used pin # 43 which controls ignition switch. The wire is a black wire with a red stripe. It is fed by the battery so it gets 11-14 Volts of power when your ignition key is in the on position. Follow the above steps except, you will be wiring the orange and red VAFC wires into this ECU wire. You will need to make two cuts into the wire cover on this ignition wire, about 1" apart. Make sure you connect the orange VAFC wire closer to the ECU plug than the red wire. Tape and secure both connections individually and then tape the entire area again.

9) Find a ground source on your ECU. I used pin # 48 (black wire) which is ECM ground and is grounded to the engine block with the ignition in the on position. Follow the same steps as above, but this time make sure you connect the BROWN wire closer to the end of the ECU plug than the Black wire.

10) The only remaining wire you will need off of the VAFC is the pink V-tec (VVL) solenoid output wire. You can leave all of the remaining VAFC wires in the ECU box or in the firewall or hanging in the engine bay, wherever works best for you. Just make sure you tape/cover the ends to keep out water and moisture and avoid a short out which could damage your engine/ECU or the VAFC unit. Run the pink wire outside of the ECU for access.

11) Check to see that all of your connections are tight and secure and taped up properly. Re-install the ECU back into the firewall in reverse order of the first 5 steps.

12) Find the pink VAFC wire, slide a piece of heat shrink over the end. Get an appropriate butt connector, slide it over the wire and with your crimping tool gently crimp to secure the wire inside of the connector.

13) Locate your VVL solenoid wires. Tie the two brown wires (one from each solenoid) together neatly and secure the wire (peel back cover 1/2" first) into an appropriate sized butt connector and crimp.

14) Run a 14-18 AWG (18 AWG is better) wire between the two butt connectors you have just set-up and make the necessary connections. Slide the heat-shrink tube down the wire to cover your connections, carefully apply heat until it shrinks. Use tape to finish the water-tight connection.

15) Take the remaining two wires (one from each solenoid) and tie them together neatly and place them inside a butt connector and crimp as above. Make sure to slide heat-shrink tube over the wire before you make your final connection.

16) Cut a piece of wire appx 8-12" from the 18 AWG wire that you purchased, cut back the cover/sleeve about 1/2 to 3/4" on both ends. Secure one of the ends into the butt connector you just set-up in step 15. Heat-shrink and tape to secure connection.

17) Now you only have one connection left to make. You need to ground your VVL solenoids. I chose to ground mine to the engine block. Right under the VVL solenoid housing (under solenoids) is a spot on the engine block that is threaded to accept a machine screw. This will be your grounding location.
Connect a "ring terminal" to the final last wire left to connect. Secure with tape or heat-shrink or both. Slide the ring terminal over the appropriate sized machine screw and ground the connection by tightening the screw. Source out the appropriate sized machine-type screw before starting.

18) Check to make sure you have completed all of the steps in a safe and secure manner. Check for loose tools and debris and clean.

19) Re-connect the negative terminal of your battery.

20) Leave the hood open. Turn the ignition key to the "on" position but DO NOT START the car!!! Check to make sure nothing is smoking/burning or smells funny. If everything appears to be okay, you can now begin to follow the steps in your VAFC manual to tune/set your VVL engagement/disengagement points.

** Note you will not be able to tune your air fuel maps. This unit is designed for a MAP sensor and NIssan uses a MAF sensor. So, unless you have a stand-alone engine-management unit you will not be able to use any of the functions except VVL engagement. If you have stand-alone you will have to connect the grey (VAFC) TPS wire and the yellow/white (VAFC) pressure signal wires when you have the ECU out.**


Remember though, the SR20DE ECU is not meant to supply fuel for VVL's higher fuel needs. You should make sure to have an SAFC or Greddy (E-manage/Ultimate) or a similar type unit to "tune" your air/fuel/timing maps to supply the proper ratios/figures so you don't run LEAN or damage your engine because of a mistuned ECU. A tuneable ECU is best, especially if you are using the DE 259cc injectors. The VE 333cc (or bigger) injectors are recommended!


Remember to always do things safely. The above mentioned steps may not be the best way and I cannot guarantee it will work for you but it worked for me without a problem so far. Soldering and heat-shrinking of all connections is generally considered to be the "best" method. This is an easier/quicker way!!

You can now enjoy being a member of the "NEO VVL" member's club.

good right up