Need help on how to recalibrate my speedo

My speedo is now off by 6-7 mph due to ring and pinion change. Iv pulled up online that some guys actually replacing the speed sensor gear to recalibrate there speedometer. How and where do i start with figuring out how to do this? Any advise will help hear.

 

Subd

 

Good question. I am in the same boat..

 

Ok this is what I think. I have owned a couple lifted vehicles and they always seem to change. Between changing gears, changing tires things are always changing. What I have ended up doing is getting a electronic recalibrater. The one I have is from 12 o'clock labs. It intercepts the signal from the speed sensor, changes it by a set percentage before it goes to the speedometer. There is a chip that you can change the percentage to a figure you figure out by dividing what the speedo is reading to your real gps speed.

A new speedo gear costs about $40 now a days. Or you can get this thing for like $80 and can change it an infinite amount of times, like if you put smaller tires on for winter or something, or go bigger in the future, or change gearing.

HEre is the link
http://shop.12oclocklabs.com/index.php?route=product/product&product_id=59

and a vid they say for motorcycles but it works great on a rig too.
https://www.youtube.com/watch?v=iScrjr7FxDM

 

You can change out the speedo gear as well to get it closer...

 

http://www.tacomaworld.com/forum/1st-gen-tacomas/148875-truspeed-speed-sensor-calibrator.html

Not trying to bust you on this,,just curious on this unit you mention.

 

Mine doesn't move from 0 until I do about 10 mph. I'm guessing from the bigger tires. Will this work the same way?

 

and with the 12 0'clock labs unit you can change to read KPH on your MPH speedometer.

 

I actually never did get that unit because i figured i was going to regear in the future so id deal with it then. 3-4 mph was tolerable, but 6-7 is annoying. Matter of fact i totally forgot that i had already started a thread on this, sorry about that. Now i will say that i did purchase a Dakota Digital unit but had problems getting it to read right and my speedo needle would jump when i had it installed so i removed it and dealt with the small speed difference. But now i have to do something because it is way off.

 

Now this unit looks pretty simple and straight forward to set up, unlike the DD unit i tried... Im assuming you have this unit installed on your Tacoma currently?

 

I do and it works great. But I have an Atlas transfer case in mine not a Toyota, bu the numbers work the same. My buddy has one in his Jeep also and he loves it I like the extrea stuff too.

And I know what it is like I drove my Cherokee for 5 years with the incorrect speed readout I always had the GPS up so I knew how fast I was going.

 

I watched to video and noticed he had a code he was using to program the unit. How and were do you get the code to program that unit to work with my setup. How did you program yours and how did u figure out your code? Are u taking your gps reading and your speedo reading and getting a ratio to program the unit or are you using something else?

 

As mentioned in one of the threads linked, a scangauge will do wonderful things and can be calibrated for different tires and gears.

Also, the speedo gear can be switched out. Stock speedo for the V6 manual 4x4 is 30 tooth. I think this is the same for others but not sure. adding or subtracting a tooth in the count is roughly a 3% change. Need to calculate the ratio change from stock to the new gears to find out how many teeth to add or subtract. Then have to find the part number.

32 tooth part number is 33403-39425
33 tooth part number is 33403-39415

Theoretically, you can't add or subtract teeth without changing the diameter of the gear. Peeps have raised concerns about larger count gears not fitting correctly and causing premature wear. I'm going to try it out to see if it is workable.

 

Hypertech.

http://www.hypertech.com/products-speedometer-calibrator.aspx#in-line

 

It gives a little formula in the instructions. But its pretty easy like if your speedo is reading 70mph and you are actually going 60 your speedometer is reading low, so you need to rise it, so it needs to be positive. So once you figure that out you take the smaller number divide it by the bigger number so 60/70= which gives you about .85. Then what I do is subtract that by 1 so that equals .15, which is 15%. So that means your speedometer is 15% off. So then you would enter +15.0. To get the formula the faster you go the closer you get on the factoring, where if you were to figure it out going slow you would have more error in reading the speedometer. It sounds complicated but there are calculators on the internet too to figure it out.

I don't know the taco case is but on the NP231 in the Cherokee you rotate the mount around to fit different count gears in the speedo housing so it is made for different size speedo gears you don't have to worry about it wearing the drive out. but the new gears for tacos cost $30 for a little plastic gear set. Why not just get the $80 12 o'clock labs calibrator the cheapest one out there and infinitely adjust the speedo output. (I actually don't work for 12 o'clock labs)

 

You can buy a digital correction device from Dakota Digital and dial in your corrections on the fly. They are about $70-$80 online. Then you have to splice it into the wire that goes from the speedo gear to the speedometer. It fixes speedometer, odometer, and cruise control. I just did this a few days ago. It was fairly simple. I followed this tutorial:

http://www.expeditionportal.com/forum/threads/43492-Speedometer-recalibration-via-Dakota-Digital

If you have any questions, let me know.

 

I still do have the Dakota Digital that i bought about a year ago and i couldent figure it out Everything was hooked up right and the sensor was getting the signal, i just couldent calibrate it, while holding the UP and Down buttons. So i gave up and figured i would give it another try after my gear install... I need it more then ever because my speedo is overshooting what my actual speed is. I want to give this another try but i need help on how to actually program the units (Coarse and Fine) settings.

I will say this though, when i did hook up this unit i DID NOT program fine and coarse settings so maybe thats why i wasent able to get it to work. I still have the unit and iv got all the wiring already out of the way so all i need to do is resplice my wires, hook it up and im ready to go.

Any help and detailed instructions on this would be great, because the instructions dakota digital gives you.... well it might as well be in Spanish

Thanks in advance

 

My speedo was off by about 10mph because of re-gearing. I didn't bother with fine and coarse settings. I couldn't decipher the chart in the back of the instructions, so just followed what I read in other postings, and lo and behold it worked. Are you sure you wired it correctly?

Pink- power
Blue - ground
Green/Red - signal.

Cut green wire and feed to input. Run wire out of output 2 and onward to the harness.

All switches set to off.

I downloaded the app "speed box" for my iphone. I got on the highway and held a steady speed and waited for the app to register it properly. Then, I pressed and held the down button on the DD until the needle began to drop. Repeat a few times until you are dialed in. The buttons are not too responsive. You have to hold them a few to get them to start attenuating.

After that, I checked the accuracy at low speeds and it was still spot on.

 

Also, did you get the SGI- 5C?

 

Yup, i have the SGI-5C. Im in the process of hooking it up now. I have the 12V wire spliced into an acc wire that is connected to the ignition switch. I accidentally had it did previously spliced into a wire that was receiving .15V with ignition turned off. Not sure if that had anything to do with my problems but i took care of it and found a correct 12V source. One question i do have is that i am currently using 18 gauge wire, does that make a difference or should i use 20-22 awg wire?

Thanks again