Truck top speed 72 now 67 after new ECM

He’s saying that after a predetermined time running 67, you will be rewarded with extra speed to be used for passing for example, for a limited time. If that truck was originally bought for a fleet, and the ECM was flashed for that serial number when replaced, it is possible that it has the “slower/fleet spec” flashed to your new ECM. Rather than going through and copying your old parameters and installing them.

 

As others have said.

First truck company job was 2001 or so century. They had it set up on that MPG/speed reward system.

Idling all night would cause it to run 65mph for 2-3 hours the next day, then the MPG would improve over the threshold, and give you back a 70mph top speed.

Many variations of ‘driver reward’ settings that can be applied.

 

those Century's were good trucks back in the day.

was it the S or SS that was the upgrade one??

 

They were good trucks. When they were designed, from a clean slate, it was a requirement that any component on them must be able to be removed by the designer, in at least book time, or it had to be reworked to do so. Dashboards still fell apart though if ya had to go into them a time or two. When first seeing one it was thought to be a bear to work on which it wasn’t at all. Nothing in comparison to the things out there now, lotta stuff crammed into smaller spaces.