h0101 timing drops out at 80 mph

[fatelvis7]

Hi guys , I could use a little help here...
The only thing I changed on my tune was to convert my speedo to double the value. H0101 meaning my speedo read 20 @ 40. Now the speedo is dead on but at 80MPH the spark drops out to limit the speed.
any help?
02 camaro ls1 4l60e 3:42

[Taz]

Not sure what your goal was by changing H0101, but it sounds like your are hitting the 160 MPH limit in H0109 - although at 80 MPH.

[fatelvis7]

Not sure what your goal was by changing H0101, but it sounds like your are hitting the 160 MPH limit in H0109 - although at 80 MPH.

You nailed it, thanks.
H0101 was changed by the speedo correction function. I didn't realize it affected other parameters.
The reason for the change is my somewhat elderly digital dash in my 49 Chevy truck is unprogramable. So my bright idea was to correct the signal out of the pcm to compensate.
It worked by the way, with your help of course.
( Street rods are somewhat of a rig job)

[Taz]

Thank you for the explanation of the issue ... I understand now.

You may (or may not) find that changing H0101 has other effects that you did not foresee, and do not want.

For this type of issue, you could leave H0101 alone, and try correcting your digital speedometer by changing H0105 from the OEM 4000 PPM, to 2000 PPM. This should cause the speedometer to read twice the speed that it had initially.

[fatelvis7]

I like it!, thanks, i'll give it a try.