mendezbp70

Need help if anyone knows how to or successfully did use FJDS software to flash the gear and tire change? I was able to make the change in "Programmable Parameters" to 3.73 and 255/45/18 wheels, but when I look at what the PCM says on Forscan or my Autel, it still says 3.31 still for the gears. When I go back into FJDS, it still shows the change I made. I did a drive and it still seems to be about 10mph faster then what I am really doing. I'm not sure if I am missing a step or not. FJDS also says I have the most current file loaded. Any suggestions would be appreciated!

hammeron

i have never used it, but from what i can see online, the sequence is as follows:

ID the vehicle
Toolbox Tab
Module Programming Menu
Programmable Parameters
-Here you make your tire value changes....
Module Programming
----here is where i think you have to go into
Module Reprogramming to actually update the PCM.
if you do not, the change you made is only on the PC itself and not in the PCM.


i used this, to read up on the FJDS

https://www.obd2.com/support/reprog/...User_Guide.pdf

mendezbp70

It automatically flashes after you make a change. I changed the ratio back to 3.31, flashed, then changed back to 3.73 and flashed but still reads 3.31 on autel PCM live data.

Derf00

well obviously the data is not getting flashed to the PCM. If you've ever flashed the PCM on these cars it take a few minutes. It's not just a 'Click' and set type of event. Why it's not flashing, don't know. I've never used the software you're using. I just use my handheld tuner if i make a change.

I don't know of any device or software that flashes a PCM as you make changes. They all require you to make changes in the software, then confirm your selections/changes before flashing. Flashing on these cars is never instantaneous.

mendezbp70

Well I figured it out. It will not let me change it to 3.73. every time I did it would default it back to 3.31 in the pcm. I changed it to 3.55 and it stayed. I changed it to 3.73 and it defaulted back to 3.31 again so I am stuck with it at 3.55 unless I get a custom tune..

danzcool

doing the math, you could leave it at 3.55 and fudge the tire size to 245/40/R18 to get the same speedometer measurement as 3.73 w/255/45/R18

mendezbp70

The setting with the lowest rev per mile to get close was 235/50/18 which is not much. I have to go with less revs to counter the faster reading. With 3.73 and 255/45/18 on stock numbers it was about 12mph fast on the speedometer when my true did was 80mph. With just the tire change in the ECM it was about 11mph faster. With the 3.55 change and back to stock tire size, it should put me about 5-6mph fast. We shall see tomorrow.

danzcool

But you said it never took the 3.73, and reverted to 3.31 whenever you tried to set it that way. And yes, my calculation had it about 5.5 miles fast with the actual tire treads, that's why I said 245/40/18 to slow it down by 5.5mph.

mendezbp70

I was able to set it to 3.55. changed the tires to get 761 rev per mile instead of 772. I'm about 5-6 mph off so it's as good as it will get. Thanks!

Derf00

What you are describing might be an issue with using a ford program tool to program your car. The options list for the software is probably locked to what build options are elated to your VIN or As Built Data.

Are you automatic or manual transmission? Automatic never had a factory option from ford for 3.73, only 3.55,. That's the possible reason it won't transfer the information when you select it. Another one is that your As Built Data just doesn't offer it with the packages your car has installed (if you're a manual).