Interesting discussion over on the COFans board with a fuel systems engineer involved. This post was particularly illuminating in response to a vendor who sells purportedly higher quality injectors:
I recall GDE saying that the GM settings have the pilot injections on all the time. GDE turned the pilots off when they were deemed to not be necessary. I believe this includes at idle. My truck does seem to be a little more "diesely" at idle with GDE's settings, that immediately goes away once revs rise. I actually like the extra bit of clatter at idle. Pulled all the sound deadening foam off the top of the engine to maximize the diesel vibe, cuz I am a child at heart. Have also gotten a few confused looks from big diesel truck owners and even had a few fuel pump chats with them as the big diesel owners were unaware that the twins had a diesel option
Anyway, some good discussion in that thread. Talking out my ass here, but stock trucks with failed injectors makes me wonder if GM leaving the pilot injections on all the time is too much for the original Denso injectors. Perhaps the "injector failures" are really just due to lazy OEM calibrations which leave the pilot injections on all the time, which could work the injectors harder than necessary.
It also makes me wonder, if that is indeed the case, why GM would not simply change the settings instead of going through the trouble of updating the injectors and head in the '18 and later engines while they were at it. GM did issue a recall card in the mail to change the settings regarding the emission sensors. Who knows if GM changed anything else, maybe they did change the injection strategy also. All I know is my truck still ran like a farm tractor on GM's updated settings vs. GDE's.
Here is a link to the thread, the above quoted bit as near the end:
Hi guys I haven't been on here in awhile, well my little 2.8 truck turned 5 years old (90k miles) in March and as a gift to me it died ☠. Sounds like the #1 injector took out the piston. I'll know more when I pick it up tomorrow. I've seen a couple of others who had injectors fail and wipe out...
www.coloradofans.com