cheapest way to flash computer for tire size

[qumanchew]

k, a bit of real wisdom here now,,

if you put on taller tires and regear for them, you don't need to recalibrate the speedo,,

if i run 33 inch tires and my speedometer is only off by like 1/2 a mph and that is with 4:10 gears,
it had 3:73 stock,

reflashing the computer may settle the issue that way, but it is incorrect to do it like that,, the truck will lose power cause it is trying to hard to lug the big tires ,

I don't think you're following what I'm trying to accomplish. I didn't re-gear to compensate for the larger tires. If that was the case I would have geared it lower (numerically higher). I put on taller tires and geared it up (numericaly lower) to get my cruising rpm's down so the diesel engine is in it's sweet spot when cruising at highway speeds.

 

[05dakotatrac]

I read about it in the re gear sections. That the second gen expos like our tracs run a colored gear on the rear end that calculates the speed and abs. Might want to look into changing the colored gear

 

[ramren16]

I read about it in the re gear sections. That the second gen expos like our tracs run a colored gear on the rear end that calculates the speed and abs. Might want to look into changing the colored gear

I can assure you there is no colored gear, its all controlled by the abs sensor in the rear I believe

 

[GJarrett]

I tried to order the Superlift TruSpeed recalibrator last week. It was put on backorder but I just received an email stating that they have discontinued producing it. Evidently it is no longer available.

 

[qumanchew]

Yea, I'm in the same boat. I just got a notice from Summit that the truspeed is no longer available. I guess my only option is to buy a tune for the programmer.

 

[roamer37]

You guys need to listen changing gear ratio does nothing to the speedo it runs off the ABS sensor on the ring gear, it reads the same no matter what ratio you have. The diameter of the tires rev per mile of the tire is what affects your speedo and odo. That's it x cal or ngs can change the revs per mile in the processor. You can measure how far the tire goes per rev and then divide it into 5280 feet or go to the tire manufacture's web site and see what it is. Any other means will be inaccurate period.

 

[qumanchew]

You guys need to listen changing gear ratio does nothing to the speedo it runs off the ABS sensor on the ring gear, it reads the same no matter what ratio you have. The diameter of the tires rev per mile of the tire is what affects your speedo and odo. That's it x cal or ngs can change the revs per mile in the processor. You can measure how far the tire goes per rev and then divide it into 5280 feet or go to the tire manufacture's web site and see what it is. Any other means will be inaccurate period.

If changing the gear ratio does nothing to the speedo then why did it throw mine off so much when I went from 3.55 to 3.08?

 

[roamer37]

please get out a shop manual and read all about it..

 

[NICE59FORDF100]

ok guys, simmer down.

As far as the tire rev per mile, yes, that will affect your speedo. as far as the dealership telling you they can only change to stock values, thats half correct. with ngs, wds, or ids, you can change the rev per mile to anything you like (its a five digit number, for example: 00692). in IDS, the computer currently used by ford dealerships, there is a section of programming that allows a tech to choose a predetermined tire size, or they can enter their own number. as far as the gear ratio, yes, that can be changed as well. a pcm tune will not help as the programming done on the vehicle to change all this is done in the abs module. hope this helps.

 

[qumanchew]

please get out a shop manual and read all about it..

I just did. The VSS (Vehicle Speed Sensor) on an 03 Sport Trac is located in the tail housing of the transmission , in a 2wd, and the transfer case in a 4wd. So here's how it works: the sensor reads the speed of the output shaft and also the drive shaft since it spin at the same rate as the output shaft since they are directly linked by splines. When you do a gear change in the differential the tires will make more revolution per turn of the drive shaft, or less depending on if you gear up or down. The drive shaft will still be turning at the same rate at any given rpm however you will be traveling faster or slower at that same rpm. That, in a nut shell, is why a gear change will throw off you're speedometer.

 

[just1me]

I believe for the Explorer, and the early 2001 Job 1 Sport Trac the speedometer worked off the ABS module which drew a signal from the rear abs sensor, but the late 2001 Job 2 to 2005 Sport Trac worked from the PCM which drew a signal from the OSS sensor on the transmission.

I recently helped someone who swapped a 5.0 and 4R70W into a late 2001 Job 2 , and to get the speedometer to work, he had to use the Explorer abs module controller on his abs module, and wire in the g-sensor from the explorer, and use the explorer rear abs sensor, that was it.

 

[GJarrett]

Yea, I'm in the same boat. I just got a notice from Summit that the truspeed is no longer available. I guess my only option is to buy a tune for the programmer.

JET makes one called the "Accu-Speed"; part # 50110. Jet doesn't have the best QC reputation but I'm gonna order one of those and see how it does.

 

[NICE59FORDF100]

This is getting me thinking about buying a second ngs and having it as a mailed loaner program type of deal lol

 

[GJarrett]

Regarding the confusion concerning whether a gear ratio change affects the speedometer: Explorer VSS modules are variously positioned at the transmission/transfer case or rear differential depending on year and model... it is not the same for all Explorers. So where your VSS is located will determine whether the speedo is affected. For some it will, for some it will not. So all of you are right

 

[qumanchew]

JET makes one called the "Accu-Speed"; part # 50110. Jet doesn't have the best QC reputation but I'm gonna order one of those and see how it does.

Thanks for the info! I just ordered one from Summit.

 

[GJarrett]

Well, I just realized something.... I still have Herc in my driveway, and many years ago its computer was reflashed by a Ford Dealership to match 33" tires. I don't need to mess with this Jet chip; I can simply swap in Herc's PCM and that should take care of me.

If anyone is interested in my recalibration chip let me know, I'll sell it cheap.

 

[NICE59FORDF100]

no no no!! Dont swap the pcms!! if you do, you will need to reflash it for the different set of keys (read: PATS) and also the tire size isnt saved or programmed in the pcm, its in the abs module. if you swap that, then yes, the tire size issue will be resolved.

 

[GJarrett]

Thanks, I'll swap the ABS module.

 

[qumanchew]

I got the accu-speed and installed it yesterday. It worked great, was easy to install and adjust. My speedo is now right on compared to my GPS. If anybody is interested in the SCT Xcal 3 I am going to list it in the for sale section.