$58/59 speedo help.
 

ok so here's what i got.
i've check the mag input box. i've got a 3.73 gear with a T56, vss output hooked to a repinned 7730 ecm running code59.

my road speed sensor constant set to 11421.29. which is dead on my speed of my gps in tunerpro. but i can't get the speedo to read right. the best i can do is 10mph high. the road speed pulse divisor is set to 165, with going from 155 to 175(by 2s, yes that was a lot of chips. thank you prominator) not changing anything. anything more or less makes the dash speedo read higher. the range in tunerpro goes from 0-255.


i've read about the $8D being bits and was wondering if anyone thats seen the code knows how the divisor works for $58. i've tried a lot of random numbers in there and all i come up with is 155-175 all reading 10 high and either way making things worse. not that i know much about it, but maybe the scale (0-255)is wrong for this? i know the sy/ty guys don't use the mag input, so maybe they haven't spend much time testing it and got the conversion wrong? i'm just reaching here.

any ideas would help, i'm lost... the only idea i had was to make it read 10mph lower in tunerpro and hope the output drops by 10 too. not sure if there will be any drivablilty issues from the ecm thinking its going slower than it is.

i miss my cruise and need to hook it back up.