leres
February 24th, 2005, 06:32 PM
The speedometer parameters page doesn't work the way I would expect; it seems likely it's somewhat broken. (Am I really the first to program a gear ratio change?)
I've got a 2000 SS with a manual transmission; I went from 3.42 to 3.73 gears. The stock VSS config is 17 pulses/rev, 2766 ratio and 47015 pulses/mile. If I enter 3.73 and click on update, the ratio changes to 3016, pulses/mile goes to 51277 and the adjustment percentage goes to -9.06%. Good so far.
Now I press "save" expecting it to update the changed parameters (VSS pulses/mile and diff ratio). It changes the diff ratio to 3.73 (ok) but the only other parameter that gets updated is the vehicle speed sensor ratio which changes from 805.1953 to 805.0000. I'm not expecting that to change (isn't it independent of the rear end ratio?) The vehicle speed sensor pulses per mile parameter stays at 47018. Even more bizare, back in the VSS configuration window, pulses/mile have changed back to 47018 and ratio has changed to from 3016 to 805. (What is ratio supposed to be in that window anyway?) If I click on update again, the values go back to what the were the first time I clicked update with 3.73 as my new ratio.
The get around this I manually entered 51277 as VSS pulses/mile (and reset VSS ratio to 805.1953). However I notice if I save the config and exit and open it again, the value has morphed to 51276.
One other question, is the maximum vehicle speed range really 0-256? I always figured it was stored in a byte so it would be 0-255. I was tempted to set it to 256 and see if it wraps to zero but I didn't have time...
I've got a 2000 SS with a manual transmission; I went from 3.42 to 3.73 gears. The stock VSS config is 17 pulses/rev, 2766 ratio and 47015 pulses/mile. If I enter 3.73 and click on update, the ratio changes to 3016, pulses/mile goes to 51277 and the adjustment percentage goes to -9.06%. Good so far.
Now I press "save" expecting it to update the changed parameters (VSS pulses/mile and diff ratio). It changes the diff ratio to 3.73 (ok) but the only other parameter that gets updated is the vehicle speed sensor ratio which changes from 805.1953 to 805.0000. I'm not expecting that to change (isn't it independent of the rear end ratio?) The vehicle speed sensor pulses per mile parameter stays at 47018. Even more bizare, back in the VSS configuration window, pulses/mile have changed back to 47018 and ratio has changed to from 3016 to 805. (What is ratio supposed to be in that window anyway?) If I click on update again, the values go back to what the were the first time I clicked update with 3.73 as my new ratio.
The get around this I manually entered 51277 as VSS pulses/mile (and reset VSS ratio to 805.1953). However I notice if I save the config and exit and open it again, the value has morphed to 51276.
One other question, is the maximum vehicle speed range really 0-256? I always figured it was stored in a byte so it would be 0-255. I was tempted to set it to 256 and see if it wraps to zero but I didn't have time...