Changing Tire While Building a Tune

[DieselDix]

Hey all. I have been writing tunes lately and having a blast with it. I'm getting pretty familiar with the tuning basics and some tougher ones. One proplem I keep running into is trying to correct the speedo for bigger tires. If anyone can chime in on this I'd be much appreciative. Ha sorry for the Title. Didn't see it until it was to late.

[SASDakota]

I initially clicked on this thinking you were worried about flashing the truck while changing a tire. I applaud the efficiency of time but just wait the 10 minutes give or take. lol


Then I read your question. The tire size is not housed in the ECM so you cannot change it with EFI Live. I use a dealer level OBD scan tool that can communicate with the ABS module.

[DieselDix]

Ok that makes sense. My next two questions are, so what about the tire section in the maps that asks for a value? If I can't get it through EFI Live, would the dealer help me out with it?

[SASDakota]

Ok that makes sense. My next two questions are, so what about the tire section in the maps that asks for a value? If I can't get it through EFI Live, would the dealer help me out with it?

1. I am unsure of what, if any, use that parameter has. It will not make any change to the speedo I know that.

2. That is a question for the dealer.

[DieselDix]

Ha ok just called the dealer and they said they can only go up to a 33" tire. Does your scan tool let you go bigger?

[2007 5.9]

Change the VSS to reflect the % off your speedo is and it should work

[Move'n Up]

You can use a Smarty S-06 to change the ABS programming for tire height adjustment from 22.5" to 44". Afterwards Return to Stock and that setting will remain, only the ECM will be returned to stock. Now re-flash the ECM with your EFI Live tune.

[DieselDix]

Alright thank you everyone. I'll try those and see if they work.

[DieselDix]

Change the VSS to reflect the % off your speedo is and it should work

How do I do this to the VSS?

[2007 5.9]

How do I do this to the VSS?

Determine the % off your speedo is and either add or subtract that % from the 8000