[Power Hungry]

Originally Posted by JackandJanet

You can actually go through all the settings without changing anything just by hitting Enter at each and then hitting Enter again to accept the value once you've seen it. When you're through looking or customizing, hit Enter on the "Done" option and you'll be told to turn the key off and then back on.

If you've gone through the custom options and looked at any of them (or changed them) the programming process will take quite a bit longer than if you just skip the Custom Options step. Don't worry, just make sure your battery is healthy and that your headlights, AC blower and radio are off to minimize battery load. Don't do it in really cold weather either.

- Jack

With the exception of the tire size and gear ratio (TS/GR), everything displayed in the custom options should be correct. I've mentioned this elsewhere but I'll post it again here for reference.

The F-150 PCM is broken down into 3 sections: RTOS, Strategy, and Calibration. There is also a small (256 bytes) section called the VID block that stores the vehicle specific parameters like tire size, gear ratio, and VIN number. It looks a little like this...

0x1:0000 - RTOS
|[VID]
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0x50:0000 - Strategy
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0x58:0000 - Calibration
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0x60:0000 - Memory End


When our programmer modifies the memory, we only read and write the Calibration section of the memory. Ford, in its infinite wisdom, saw fit to not only put the TS/GR in the VID block but also have values that are located in the Calibration portion of memory.

In normal situations, the PCM uses the VID block for TS/GR information. If you have stock tires or gears we don't bother that setting.

When it is necessary to make changes to TS/GR, we have to make those changes to the Calibration because we do not access the VID block which is stored in the RTOS.

The confusion comes when we grab the default values located in the Calibration. These values have no relationship at all to what TS/GR is actually in the truck and are simply place holders for arbitrary data values. Some trucks are 3.55, some are 3.73, and we've even seen 3.31. When we change TS/GR, we write the values into these spaces and then set a switch that tells the PCM to ignore the VID block and use our new values instead.

Since we assume that neither value in the Calibration is accurate, this is the reason we always say to set BOTH TS/GR values. Don't change one or the other and expect it to all be correct.


One other note about custom tuning... Viewing the custom options sets a flag that tells the programmer to write those values to the PCM even if you didn't change it. We recommend that if you don't plan to change it, do not go into it. You may take a 20 second reprogramming session and easily turn it into 2 or 3 minutes. Shifts are especially slow to process so use those sparingly.

Does any of this make sense? I hope so.

Take care.