RE: CM2250 boost

[Rawze]

(04-17-2019 )Jose9640 Wrote:  I have a cm2250 that started acting up past couple of days. Boost will go to normal then it either cuts off(back to 0) the. Shoots right up. One one ocassion it spiked to nearly 50 then came right back down to 30. Only codes it has is 2554 for erratic exhaust pressure. I already put a new sensor. What else should I look for? Truck is de-mandated.

'Jose9640' sent me the program out of the truck. I took a look at it and for sure it is a bad de-mandate file. Looks just like the same exact stuff that has been traded, and passed around on those auto tuning/pirate software internet forums.

Things that are missing or are incomplete...

-- MISSING: engine operating mode control re-programming to pevent the engine going into SCR warmup and other emissions modes.

-- MISSING: corrections to fall-back emissions logic to prevent incorrect/unstable altering of injection timing, boost, and fueling.

-- INCOMPLETE: EGR system removal logic is very incomplete.

-- INCOMPLETE: DPF soot accumulation locgic is still in place.

-- INCOMPLETE: EGR gas request logic is still in place.

-- INCOMPLETE: Injection timing, boost, and fueling offset logic based on EGR gas requests is still in place.

-- MISSING: The removal/proper re-mapping of the EGR piping volume and flow estimates in the intake boost level control logic.

-- MISSING: re-mapping of the fall-back/alternative injection timing and fueling pressures for operations without EGR gas to prevent high detonation rates.

-- MISSING: re-programming of the turbocharger for engine operations with the EGR disabled/blocked.

-- MISSING: Switching off of the corrections logic of injection timing and fueling based on SCR catalyst ammonia production.

-- MISSING: Switching off of the NOx sensors and their associated logic systems.

-- MISSING: proper switching off of the EGR Delta-P sensor.

-- ADDED: The following fault codes have been added to the fault block-off tables in the ecm so that it can no longer report them due to incomplete 'delete' programming. None of these codes are necessary to block/suppress if the de-mandate job has been done correctly...
---- ---- 3138 (egr/delta-P outlet pressure faults)
---- ---- 2771 (engine NOx sensor missing)
---- ---- 3232 (dpf NOx sensor missing)
---- ---- 2636 (turbocharger missing/unplugged)
---- ---- 687 (turbocharger speed sensor missing/reading low)
---- ---- 3597 (DEF controller module unplugged)
---- ---- 1867 (egr temp sensor unplugged/missing)
---- ---- 1942 (crank case pressure sensor missing/incorrect)
---- ---- 3733 (crank case pressure too high)
---- ---- 333 (injector error)
---- ---- 1896 (egr valve out of calibration)
---- ---- 2272 (egr valve disconnected)


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Easily, the improper engine mode control (or lack thereof for re-programming it) will cause the things you are describing in your original complaint. The engine is most likely cranking up and then going into SCR warmup mode ( because that is what they are supposed to do from factory) and it never really leaves this mode because it cannot satisfy the condition with all the SCR logic suppressed. - this makes for some seriously unstable conditions with everything from the injection timing to the turbo operation itself.

It is also quite obvious when looking at that table of blocked ecu codes, that the program was likely made for a truck where someone removes the VGT turbo and installs something of lower efficiency due to lack of being able to properly control it. It is easier for most shops to remove the VGT and -up-sell- some garbage after-market manifold and turbo because they can make a higher profit off you all while hiding the fact they are just not able to properly re-program the factory VG Holset (the most efficient turbo out there already) for proper operations without that EGR/DPF system.

It is also apparent that someone seriously did not know how to properly turn off most of the emissions systems, so they resorted to blocking all the alarms the ECU was reporting in attempts to shut the CEL light off in the dash and fool the truck owner into think everything is ok. - This is typical of the 'poke and guess blindly until it starts working' amateur hack-n-slash delete programming that gets passed around on the internet like some school-boy in a prison yard. Trouble with this approach is that the ECM is very unpredictable in its outcomes, so one person with this kind of programming may think everything is ok (until their engine blows up a few times), but the next guy will have nothing but problems, all while the guy doing the delete work can't figure out why some trucks seem to run ok, yet others have nothing but problems. - This is because the whole program when made in this fashion is nothing but an unpredictable, unstable, Jenna-block stack teetering on crashing down at the slightest variance.


A secondary effect of this type of code-blocking approach is that it becomes difficult for anyone to troubleshoot the engine if there are injector or turbo problems. A mechanic will chase ghosts because he can't see half the codes that would be normally be showing by the ECU. Lots of time and money are lost guessing at things when someone can't see half of what the ECM is complaining about.


I wanted to take the time to point out these highlights here because the file that was sent to me is the very definition of a 'bad delete' in all sense of the word. Most of the time a file like this would also have the power and torque jacked way up, or the timing and fueling jacked up in bad ways, but in this particular file, its downfall is the fact that it is very incomplete + perhaps too much was assumed by its author that leaving as many of the ECU's 'factory setting' alone as possible is somehow going to prevent damage. - Sorry, but it is quite the opposite, as the ECU is going to still go into its engine modes meant for emissions system control, it is still going to use settings based heavily on the use of EGR gas to hold the engine detonation rates in check, etc. but with no more gas, this thing is destined to run amuk with out of proper control turbo settings, and fret a liner out of it in short order with it programmed this way for sure.

You say in your bio. that you are a fleet owner,... I feel sorry for every single one of the trucks that have de-mandates in them if this is the case. You are on a clear path of shortened engine life with all of them.

-- The worst part of this 'bad delete' stuff of all is that whenever the truck owner learns that his program is way under par like this,.. and get back in touch with the person who did the programming, knowing the truth now, that instead of having the guy who did this type of work get in touch with others to help him improve his work, most of the time they only get arrogant and defensive. when they do this, it clearly shows the lack of character a person has real fast, because all most of them seem to care about with their customers is getting that money for the least amount of effort possible, even if it destroys the equipment in the end.