CM 2250 Fuel pump calibration what is it?

[Mikanic]

Hi everyone I was comparing dataplates between engines and noticed the fuel pump calibration number changes lets say from a 525 isx to a 550 isx both 2012MY. What is a fuel pump calibration and how do I change it? Fuel pump part # are the same.

Here is some background to why I was comparing dataplates.

I recently started looking into the demandated programs for the ISX as I have to work on trucks demandated often. (Im a truck mechanic) So I was asked by a customer that has a demandated ISX 525 1850 if I could bump up his power a bit since he is logging offroad only and has to pull load between 80-90 thousand kgs (yes we haul heavy in Canada). So I told him if he installed a Pyro gauge I would do it. Previously I had already played in his ECM because he was getting EGR diff pressure faults even tho he was demandated and was able to fix that for him.(thanks to the @m*m^2 guide) So after we installed a pyro gauge I went on and bumped up his power to 600hp and 2050 ft/lbs of torque, following the same torque curve as a stock ISX 600. I found the values I wanted in an other trucks ECM that was already at these power levels. Its important to note that I have not changed his SOI limit tables or any other tables. What I also found out was that his power levels were 550 1850, the ECM code did not match his stock one and the CPL in the ECM is at 3349 and I cant find anything about this CPL. His stock CPL is 3606. But even tho all that, it worked, went for a road test power was good, no fault, vgt working as expected EGT were good. Truck went hauling and a couple months has gone by no issues, customer says EGTs are good and everything is beautiful.

So word gets around another customer comes by asking for a bump up in power they both haul the same unit so I understood the need for more power. Both trucks are 2012 CM 2250 but this one was born with a 550 1850. But here is the twist, both were demandated by the same guy and both had the same ECM code that did not match their stock, both had same CPL 3349 rating in ECM aswell. So its fair to say they had the same file. So having a tested calibration I went on and downloaded the same file as my previous customer. But this time I'm getting the CEL when its pulling hard and fault code 559 (injection metering rail pressure to low) but only for a second and then goes inactive without letting off throttle. Driver claims the engine light has no effect on performance and the truck does have more power since I put this calibration in it. But freeze frame data does show a significant offset of fuel pressure commanded and measured.

Both fuel filters were replaced and it still has the same issue. I am supposed to see this truck in the next few weeks and was going to check fuel return flows but usually when I get a bad relief valve of injector leakage I get a fuel leakage fault. Its odd that this fault code was not in the ECM image before I downloaded the calibration and that the fault goes inactive without letting off the throttle. This is why I'm suspecting maybe the calibration, I started digging and the only difference I see between the dataplates of these engines is fuel pump calibration because I guess one was born with a 525 and the other 550.

Thank you in advance for those who took the time to read this and are willing to help.