I did a ls1 swap into s10. I used an fbody harness and trans. I used an 8.8 with 4:30 and 26" tires.

My speedo is way off. I changed tire size to 25.5 and gear ratio to 4:30 but its still reading 90mph when I'm driving 30mph. Is the s10 bcm confusing it. Or can I adjust different tables in the hptuners. Both my speedo and the speedo on hptuners read the same. Any info would help

 

Sure your pulses per rev on your VSS is entered correctly?

 

How do I know what the value should be to know if its wrong

 

Manual or automatic F body trans? Manual should be 17 pulses. 4L60E should be 40 pulses.

 

So lets say it was set on 17ppr vs the 40ppr that it should would that cause it to read to high or too low.

I'm guessing other values like ppm must be ok if the dash speedo is reading the same as the PCM.

 

Sorry it's a 4l60e

 

Then you see it should be 40, right? If it was on 17, that would be your problem.

 

Ill have the tuner check tomorrow. He is baffled on it. I'm trying to find out any info I can. He just changed my tire size and my gear ratio to 4:30 and speedo was still way high. He doesn't know what to do but my truck won't shift in auto. So I am trying to find out anything I can to fix this issue.

Thanks for the help.

 

As far as speedo goes all he did to trans tune is

Tire size 25.5
Gear ratio 4:30

I saw him change that table.