Another typical (bad) CM870 delete ...

[mikkhh]

99% of those "tuning gurus" have never even taken apart an engine or put it together.

Some guys who "do programming" flat out say that they do not fix any mechanical issues on engine, they are afraid to get hands dirty and even more afraid to admit that they are wrong.

Some keep blaming that aluminium inline6 diesel engine blocks are the culprit for cracking between 2nd and 3rd cylinders after their stage 3 or whatever of engine desctruction modifications.

Older European car engines were still based heavily on oldschool mechanical diesel injection hardware so there was still huge margin of safety compared to newer stuff that is designed from scratch for efficeincy and emissions. Also lots of euro manufacturers were cheating with emissions especially around 2005-2015 era and they used way less e g r than they should have used, that with along oldschool design also helped to keep engines together for "tuning gurus". Why those tuners did not report or knew about emissions cheating done on modern cars? To this day engine modes are a new concept to most of them.

Then something changed and car engines got developed from scratch to meet latest euro5 emissions were starting to use e g r under full load, but that thing started to happen mostly on 2010+ engines and 2015+ started to use both low and high pressure egr.

Those first engines that were made from scratch to use full load e g r and did not cheat with emissions were the ones that got plagued for poor reliability and longlife service intervals (30 000 miles for oil change on vans, 20 000 miles on cars) also took a toll on engines due to increased soot load in oil. How this is relevant to red engines? Well hook up a scan tool to any 2015+ car or truck and see live data what engine mode it is running, there are lots of operating modes, most makes have them at just some cryptic numbers, but by quessing using self study programmes or introductions of new engines they mention periodic regenerations of catalytic converters and those things fully correspond to engine mode operating changes while driving. Also dpf regenerations have different operating mode, when you fully floor engine then also mode changes, you can also look at fuel rail pressure to get a quess what combustion logic the engine is running. but some fuel systems have hydraulic amplification so the rail pressure and injector tip pressure may not be 1/1.

Keep in mind that most those "tuning gurus" started from cars and moved over to trucks. There is big difference running wise, since cars are not usually fully loaded and load on engines is quite small compared to commercial equipment. How any of them tell that it is MUST DO to clean intake etc before doing any tuning or deman? How any of them check for faulty sensors?