Holy smokes! Thanks! I think I can get to that a bit later today, if not then in the morning.

Yes, the SCT is just a FlashCal-ibrator for things like *factory* gearing (no 4.10, though) and tire size. I use it strictly for speedo correction with each new, slightly larger set of tires over the years.

I was able to get FORScan functioning on this current laptop, and the Bluetooth OBDLink MX+ up and running, and had a peek but only at the simple interface (English) for my BCM. We'll get to work in the As Built next time. Gear swap is next week! so I gotta get busy. lol.

I'll be back in here w/ the info at some point very soon. I sure do appreciate your help.

 

As Built data:

726-12-01 014B 09E3 56CE



What does that translate to?

Thanks!

 

Here is the translation ...

014B = 0331 = 3.31 ratio axle
09E3 = 2531 = Corrected tire circumference in mm.
56CE = I have no idea what this is and on a '11-14 this number has nothing to do with speedo calibration, not sure if it applies to '15-19 models.

Quick question ... is this the line number read from you ECU or was this line downloaded from Ford? If it is what you read from your ECU, it is possible it has been flashed before and could mess with our calculations.

Also, what tire size did your truck come factory equipped with?

 

The last four characters may be a cheksum? *shrug*

My original, as built tire fitment was a 245/70-17, 30.5" diameter.
Axle gearing (until next week!) is stock, at 3.31 w/ open diff.





Those figures/characters/numbers are directly from my truck's BdyCM read this morning.

My truck's ECU, or PCM, was never flashed for, or with, any performance data. The only folks that have attached anything to the CANbus port are the dealer when flashing an update three years ago, and the smog check technician at a local shop with an unblemished reputation.

I have however used an SCT FlashCal to adjust for tire size, with the last input being for my latest Toyos, the static, loaded radius of which is exactly 16", making it dynamically a 32" tire under load and underway.


Thanks for your efforts, my friend. I am indebted to you.

 

Right now my speedo is within 1 MPH of a GPS readout, and 1 MPH faster than what CruiseControl displays in numerical readout when I use that feature (which is not often). If I see 70 on my analog-looking speedo dial my GPS will also read 70, but 69 will display in Cruise.

 

So I did some calcs with your current tire (34x10.5x17) and gear ratio and have something for you to try. Disconnect the FlashCal and lets see if I have adjustments in Forscan that will accomplish the same. The reason for the test is some of the calculated numbers seem "funny" to me and this test will help validate how accurate we can get with your gear change.

Change line 726-12-01 to 0140 09A4 xxxx (just leave the last four characters the same as they are now).

Do the PCM Relearn function in Forscan (I assume you have that as the '11-14s do) and go for a test drive. Let me know if we are off by any amount and by how much.

 

I can do this tomorrow morning, but not this evening, unfortunately. Thank you again!

Now, is this intended as a test using my current axle gearing of 3.31? and just a tire calc test?

The FlashCal is never left connected, only plugged in to get a speedo change. The changes the SCT Flash Cal makes are where some of my other questions lie.

Because with the data as read this morning in my BdyCM As Built, the SCT seems to have corrected that tire circumference in mm without changing the data as read using FORScan.

I don't know how to restore any original config from Flash Cal, but there may be a setting for that. I would like to erase any input/influence the Flash Cal has had in/to my truck's PCM. Know what I mean?

Apologies if I am only muddying the water.

 

Nevermind, I re-read your request and looked at the hexidecimals... looks like just a tire circ change. Thanks!

*Edit: Rather, just a tire calculation change while still geared with the 3.31. Gotcha.

I'll report back tomorrow before 10 a.m. Pacific Daylight Time.

 

Is there a way to uninstall it - so that the speedo values are calculated based on the factory PCM only.

Looking at your AS BUILT numbers, FlashCal may be re-flashing the BCM/PCM with the correct numbers for what you are inputting for tire size and gear ratio.
Do me another favor. Go to this website and enter your VIN number and download your factory AS BUILTs from Ford.
https://www.motorcraftservice.com/AsBuilt

I would almost bet your factory line 726-12-01 might actually be ...
726-12-01 014B 0911 xxxx

... or close to it.

 

I will do that. From Ford.

But when I last SCT flashed for tire size, the 32" does not equate to the As Read in FORScan this morning.