Problems with Speedo Calc. / PLEASE HELP

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Once again it's the dreaded aftermarket 4.56 gears / inaccurate speedo problem. Please help me fix this, the last time it never worked and that accounts for the only 1 out of 40 unsatisfied customers.

I'm working on a 2007 new body style Chevy Vortec Max pickup with a 6.0 liter. He has changed the factory 3.73 gears to aftermarket 4.56 ones. The speedometer is crazy as you'd expect, but fortunately the ABS light is not on, because this vehicle has 4 individual wheel speed sensors.

So I go into his speedo calculator and input his tire size and gears. The pulses per mile change, I write it, and no change in the speedo! It shows about 20 mph when you're almost at a complete stop, and about 40 mph when you're doing about 25.

Is there a glitch or some kind of trick I have to do to get this right?
PLEASE HELP ME, I NEED TO FIGURE THIS OUT ASAP. Thanks!

[ChipsByAl]

What does the scan tool display? The vehicle may have a cluster issue.
Al

[Blacky]

Assuming the speedo reluctor ring is on the trans output shaft, then changing the gears from 3.73 to 4.56 will cause the pulses per mile to increase. The actual increase will be determined by the percentage increase in wheel (i.e. axle) revolutions per mile. The multiplier that you need to apply to the pulses per mile can be calculated as: new/old which is: 4.56/3.73 = 1.22252 So try multiplying your pulses per mile by 1.22252 and enter in the result as the pulses per mile. There is a calibration that defines the number of pulses per rev of the trans output shaft that is not yet exposed by EFILive (for the LS2 controller). We are adding that cal in the next release (asap). By not allowing that cal to be updated may be causing issues. Regards Paul

[Blacky]

P.S. Sorry about the formatting, something is up with either my browser or the forum... Paul

[Boost]

There is a calibration that defines the number of pulses per rev of the trans output shaft that is not yet exposed by EFILive (for the LS2 controller). We are adding that cal in the next release (asap). By not allowing that cal to be updated may be causing issues. Regards Paul

I was afraid of this.... I feel like the speedometer is looking at something else besides the pulses per mile (that I did increase from 97xxx to 115xxx).
Blacky, how soon can we get this fixed? What can I do to help?
Thanks!

[Boost]

Table H101 is 97010 VSS pulses per mile at first. When I add his tire size of 275/55/20, it drops to 94300. Finally, with the 4.56 gears it's 115284.
I made sure the main table had that value when I closed the speedo calc. window. I noticed that H0135 (tire size correction) does not change from 97010 (??).

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The VIN # is 2GCEC13YX71507412.
OS: 12612291
Calibration: 12612290

I am looking at schematics in Service Information. Is the computer looking at various sensors and comapring what is sees, then possibly still going with what makes sense based on engine rpm or something possibly?

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