2008 Ford F250 King Ranch 6.4L- unable to change tire size

Andysapp · Post by **Andysapp** » Sun Jan 24, 2010 3:52 pm

Hi. I have a 2008 Ford King Ranch F250 with 20" tires and have installed 17" winter tires (winter tires are not available in original size). I have tried changing the tire size several different ways (even reverting back to the original tune and going to 900 revs down to 550 revs) and the Predator U7164 shows the change but the speedometer error doesn't change at all. I have even downloaded the latest crom with no change. You did indicate that the problem may be that the Predator isn't writing to the ABS module. Any idea when I might be able to look at my speedometer and see the right speed?

unit 1: 8U7A-14C204-CF
unit 2: 7U7A-14C337-AB

email [email protected].

Thanks, Andy.

SCGt94 · Post by **SCGt94** » Mon Jan 25, 2010 11:18 am

The abs module controls tire size changes which we don't flash. It can be done by other means until i get a chance to finally look at this. Does the truck have traction control? if it doesn't i can make a custom that has your tire size, if it does then it will be permanently off while the custom tune is in.

Andysapp · Post by **Andysapp** » Wed Jan 27, 2010 3:08 pm

Hi. Thanks for the reply. The truck is a 4x4 but as far as I know it doesn't have traction control. If it helps I use the 80 HP tune for the fuel mileage.

The tires on it now are 265/70R17 down from the 285/65R20.

Thanks, Andy

2008 Ford King Ranch F250 4X4 diesel.

SCGt94 · Post by **SCGt94** » Thu Jan 28, 2010 1:39 pm

andy, who is the manufacturer of the tires themselves

Andysapp · Post by **Andysapp** » Thu Jan 28, 2010 9:09 pm

SCGt94 wrote:andy, who is the manufacturer of the tires themselves

Hi Don: The current tires are Firestone Winterforce P265/70R17. The originals were what came with the truck from the factory. B.F Goodrich I believe. Hope this helps.

Thanks, Andy.

2008 Ford King Ranch F250 4X4 diesel

SCGt94 · Post by **SCGt94** » Fri Jan 29, 2010 9:42 am

yea thats perfect, ill get back to you later today with a tune for ya

Andysapp · Post by **Andysapp** » Thu Feb 18, 2010 3:25 pm

Hi Don: My Firestone tires are rated at 668 RPM.
Just wondering if you are working on a general tire size fix or if you response got lost?

Thx, Andy.

SCGt94 · Post by **SCGt94** » Fri Feb 19, 2010 11:13 am

Working on a general fix as of right now, having some trouble getting my hands on a truck though.

I got a file i am emailing you right now..

Andysapp · Post by **Andysapp** » Fri Feb 19, 2010 4:01 pm

SCGt94 wrote:Working on a general fix as of right now, having some trouble getting my hands on a truck though.

I got a file i am emailing you right now..

Yes I got the file. Question. Since this is a FRD file rather than a CROM do I reinstall the original back up, load this one as a custom tune & install? Or do I install it over the current 80hp tune?

Thx, Andy.

SCGt94 · Post by **SCGt94** » Fri Feb 19, 2010 5:50 pm

you can just load this file to the tool then load it to the truck. That frd has the two ori's already in it. So just connect it to the pc open dsdownloader and hit send tune file to tool. Remember this tune WILL kill your traction control if it is on your truck that is. It will cause the t/c off button to stay illuminated.

Andysapp · Post by **Andysapp** » Mon Feb 22, 2010 9:28 am

Sorry Don. I installed the tune. No difference re speedometer output. I tried a couple of different tire sizes but the error remains the same. If you have an updated CROM file that might work I am willing to give it a try.

Thx, Andy.

SCGt94 · Post by **SCGt94** » Mon Feb 22, 2010 10:30 am

o rly? hmm interesting. Did you install the custom tune with all your adjustable params untouched?

Andysapp · Post by **Andysapp** » Mon Feb 22, 2010 11:31 am

Transferred the tune to the predator. Installed as custom (shown as extreme) with no changes. Applied changes after to see if there was any difference. Same results each time. Note: I just overwrote the 80 hp tune already on the truck.

Andysapp · Post by **Andysapp** » Fri Apr 09, 2010 8:32 am

An update to the custom tune you sent me:

Pros: love the fact I can actually write to the TCM. Fuel mileage appears to be better. Lots of power & nice response.

Cons: Unable to change tire size (no difference). In cold weather I had major surge issues twice coming down to idle (it revved up a fair bit before going back to idle). Once it hit DPF regen cycle it never got out. tremendous amount of power but unable to reach the temperatures needed to burn off. Essentially went into regen every day and stayed there all day long. Last one I went through nearly two tanks of fuel in regen before I gave up. Switched back to Ford original and it burned off in very short time ( I could smell and feel the difference in heat output).

Conclusion: Excellent response, good fuel mileage but lousy in regen & no change in speedometer response. Please, please include the ability to write to the TCM in the next tune.

Thx, Andy.

SCGt94 · Post by **SCGt94** » Fri Apr 09, 2010 9:33 am

andy, the 6.4 has always written the tcm

thank you for the feedback, i made progress on the tire size issue only to be slammed by 6.0 and 4.7 stuff that needs to be tested and get out.