PDA

View Full Version : *Write Up* Installing the Yellow Box Speedo Calibrator


Scuba
06-05-2010, 06:54 PM
With the addition of over sized tires and lower gears in the differentials my speedometer had a 24% difference indicating 90MPH at an actual 70. Not acceptable. :shake: Follow along as I install the Yellow Box Speedometer Calibrator (http://www.yellr.com/yb_home.htm) into my 99 2.7L 5Speed Tacoma.

I checked the Yellow Box instructions (http://www.yellr.com/yb4_insta.pdf) and checked the wiring diagram on the NCTTORA site (http://www.ncttora.com/FSM/2003/Wiring_Manual/03tacoma/systemci/019ecs3r.pdf) which led me to my conclusion of how to wire it up.

First, pull the wiring harness out from the trans/transfer case. There's 5 connectors (which I don't know the exact names of) that need to be disconnected and pushed towards the front of the vehicle.

There is the VSS connector as well as the rear o2 sensor harness on the rear end of the transfercase
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0056.jpg
This is the rear o2 sensor plug, which bolts onto the Tcase somewhere in the above picture
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0057.jpg

Moving forward there is the Tcase position sensor (passenger side) (I'm 99% sure that's what this one is called) I have small hands so it wasn't hard to get in there, but you might have to have your kid do it if you've got fat hands.
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0058.jpg

Then there is the front o2 sensor harness (passenger side, bolts into the hole I'm pointing at.)
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0059.jpg

After that you can shove the harness over the top of the transmission to the drivers side and unplug the 5th and final plug of which I do not know the name
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0060.jpg

Once you have the harness in a good spot with enough room to work (and solder) you can pull the shielding and the electrical tape out of the way to reveal the 3 wires for the VSS. They are colored as follows : Red/black for POWER. Blue for GROUND and Green/Red for the SIGNAL WIRE.

For the power and ground wire you will want to strip (not cut) about a 1/2" of the shielding off of each. For the signal wire you will want to cut it and strip back a 1/2" of the shielding on each end. This picture may be a little hard to see but will give you an idea.
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0061.jpg

From there you will connect and solder the following wires.
Red/ black from the VSS gets connected to the Red wire from the yellow box.
Blue wire from VSS gets connected to the black wire from the yellow box.
The White wire from the Yellow Box gets connected to the VSS side of the Green wire.
The Gray wire from the yellow box gets connected to the ECM side of the Green wire.

Once you have them all connected solder them
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0063.jpg

Once your connections are soldered you can wrap them in electrical tape and shove the harness back into the plastic shielding. Reconnect all your sensors and run the wires where they need to be.
I chose to run the yellow box into the cab through the shifter boot hole. The actual yellow box unit will sit in the dead space under the center console

Kind of dirty
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0065.jpg

For size reference
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0066.jpg

Here are the switches you flip to change the settings
http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/DSCN0068.jpg

That's about it. From there you will want to follow these instructions (http://www.yellr.com/yb4_calib.pdf) to figure your speedometers percentage of error and then use the correction table (http://www.yellr.com/yb4_table.pdf) to get a rough estimate of where to start off for the calibration step.

My calculations gave me a 21% difference and I ended up having a 24/24.5% difference. So leave the yellow box in an easy to reach spot so you can take a test ride and get it where it needs to be. I think it is suggested that each time you change the settings make sure you power down the vehicle.

I took a run on the highway and had to stop and change it a few times in order to get it perfect.

After that you can reinstall your shifter trim or what have you and live a happy life knowing your speedometer is freakin dead nuts accurate :smokin:

I don't know which models have the same wiring scheme, but I'd venture to say all 95.5 Tacomas and all 96-02 4Runners will have the same wiring colors. If not refer to your vehicle wiring diagram or use the method in the yellow box instructions to figure out which is which

EDIT: Thanks Erich. Links fixed
Scuba
06-05-2010, 07:35 PM
The links were broken, now they are fixed. Hope you enjoy.
Thanks Erich
troyboy162
06-06-2010, 09:06 AM
anyone know if these will work with auto trans? im probably too cheap to buy one but im not sure they play well with autos from what ive read. i dont understand why it would be an issue unless shift points are based on speed.
Scuba
06-06-2010, 10:18 AM
Shift points are based on RPM's not speed. You have a VSS ? You'll be fine ;)
Crinale
06-06-2010, 01:52 PM
my speedometer is based on rear diff ring gear speed... haha.. so i have no idea how to fix it
corax
06-06-2010, 01:56 PM
Nice write-up - I think my VSS is a bit different, will it still work if I cut and solder that big single cable going to the back of the trasfer case :roll:
http://www.postimage.org/PqXTof0.jpg

j/k, anyway I think the 5th plug on the driver side that you didn't know the name of is probably the reverse light switch
corax
06-06-2010, 02:06 PM
my speedometer is based on rear diff ring gear speed... haha.. so i have no idea how to fix it


If you're talking about the little bit on the top of the center section, that's for the ABS - you're '91 probably uses a cable at the transfer case just like mine
http://forum.ih8mud.com/attachment.php?attachmentid=120407&stc=1&d=1171253981
Crinale
06-06-2010, 02:14 PM
o really? i didnt think mine had abs... well is there anything wrong with leaving it dc-d? cuz my new 3rd doesnt have a hole for it..

sry scub, didnt mean to threadjack...
DHC6twinotter
06-06-2010, 02:14 PM
My '90 has a speedo cable at the tail housing (no tcase in my case).

Scuba, nice write-up! I'll have to look into this once I get a newer 4Runner.
troyboy162
06-07-2010, 09:25 AM
Shift points are based on RPM's not speed. You have a VSS ? You'll be fine ;)

this is an awesome writeup. ive done alot of internet surfing and youve got the most complete install instructions anywhere. i learned that my truck (96 4runner with abs) does not have VSS. the ABS trucks ive read take the signal from the wheel sensors and feed that to the abs computer. the the abs computer interoperates that and spits out a signal that runs to the dash gauges and then to the ECU.
Scuba
06-07-2010, 09:29 AM
Shift points are based on RPM's not speed. You have a VSS ? You'll be fine ;)

this is an awesome writeup. ive done alot of internet surfing and youve got the most complete install instructions anywhere. i learned that my truck (96 4runner with abs) does not have VSS. the ABS trucks ive read take the signal from the wheel sensors and feed that to the abs computer. the the abs computer interoperates that and spits out a signal that runs to the dash gauges and then to the ECU.


Really ?
Even still, you could still splice into the signal wire from the ECM to the combo meter..
YotaFun
06-07-2010, 11:17 AM
Really ?
Even still, you could still splice into the signal wire from the ECM to the combo meter..



.... I don't know about that, might mess with the ABS operation
Scuba
06-07-2010, 02:11 PM
As suggested by a member of another forum, I added in a fuse. 2.5A
Also, while I was in there, per the instructions I wrapped the yellow box in some very high tech stuff in order to keep the dust out of yellow box.

http://i11.photobucket.com/albums/a168/Sycosurfer150/Truck/Speedo%20Calibrator%20Install/IMG_0993.jpg
corax
06-07-2010, 03:20 PM
Really ?
Even still, you could still splice into the signal wire from the ECM to the combo meter..



.... I don't know about that, might mess with the ABS operation


Not if it's only intercepting the signal to the cluster - - if the signal goes into the cluster and then branches off to other modules, then you might have problems. But really, even putting bigger tires on an ABS vehicle will have an effect . . .
YotaFun
06-07-2010, 07:25 PM
I realized that, but I figured in the wonderful world of electronics if the resistance wasn't right or something that it would set off an ABS code.
04 Rocko Taco
06-07-2010, 07:27 PM
Can we not just take it to a speedo shop to have them calibrate it if you dont have the VSS or if you are afraid it will mess with your ABS?
Crinale
06-07-2010, 08:07 PM
haha, ya i wonder how bad my speedo is gonna be now <.<
Scuba
06-07-2010, 11:22 PM
Can we not just take it to a speedo shop to have them calibrate it if you dont have the VSS or if you are afraid it will mess with your ABS?


Well, the trucks have a gear inside the tail housing of the transmission and you can swap out the gears but you probably won't get it perfect. I could have swapped gears but my difference was too large for the gears to make a good difference.
If you have an electric VSS, how would you calibrate it without the box ? This yellow box does math every single milisecond to change the signal going to the ECM.

I still don't think the other "abs" concerns in this thread are valid, but I didn't feel like arguing.
troyboy162
06-08-2010, 09:12 AM
im searching to figure it out. so far it looks like a square wave that its made by the vss sensor or the abs computer. this is the signal path i read about

1. wheel sensor to the
2. abs computer to the
3. gauges to the
4. ecu/ecm

so cheap basterd that im am...trying to figure out if i can use any old speedo calibrator and splice it into behind the dash.

it got me thinking because almost all these company's sell the same unit for lots of verticals and the difference is the cable harness. and if ever unit is basically the same then there are alot of used motorcycle units available for cheap since those guys seem all about them.

so if you splice up stream from the gauges...your abs gets raw wheel spin data and everything else gets actual speed data. i would think thats the best scenario for all the systems involved but i could be wrong on alot of this stuff.
Scuba
06-08-2010, 09:22 AM
Well I mean, if altering the signal from the VSS to correct it to where it should be, how does that hurt the ABS ? I guess I'm just not sure where your guys' fears are coming from.
troyboy162
06-08-2010, 10:17 AM
i dont think 3rd gens 4runner with abs have a VSS they delet the vss and get that "speed signal" from the abs computerand. most of us should have abs since it was apparently standered on the 3.4... might be wrong on that.

but if you have abs and a VSS then the abs would run off the wheel sensors not VSS