CM2250 Poor fuel mileage

[Truckdriven]

(03-02-2022 )Rawze Wrote:  yeah,... for some dumb damn reason, a lot of programs from the factory have what is known as a "virtual sensor" switched on for the turbo speed sensor. I can only assume it is used as a backup to the real turbo speed sensor if it fails. - I personally do not know why they would do something so stupid, as it makes the ecm often not throw faults, but instead try to guess at the turbo speed whenever the real sensor starts failing. this often leads to no fault codes at all sometimes when it does so, but an engine running like crap.

I was watching turbo speed with Insite and unplugged speed sensor , reading went to 0. Ran for 3 minutes till I shut it off and it But never threw a fault code. Does this indicate "virtual sensor" is turned on in the program?

Also I ran Injector leak test and leakdown was 2090, 6k miles ago it was at 900, and 10k before it was at 340. I checked the rail relief valve and there was not a single drip. Something seems to be deteriating should I be concerned or wait till it gets worse and easier to find? fuel pump was rebuilt 17k ago.