CM871 code 2973

[Rawze]

I was sent the program from your engine. Looking it over, here are the things that are considered red flags...

* Someone attempted to strengthen the engine brake settings by increasing turbocharger VG positions during engine brake operations. This has the serious potential of causing the engine to drop a valve at high rpm and engine brake at maximum settings. This is a dangerous thing to do and this could cause someone to loose their engine, crack their head, etc. if the piston strikes an exhaust valve due to too much lag because of excess exhaust back-pressure by the high settings that someone put in the file and is demanding from the engine.I have seen many people who make this mistake, then claim they made the engine brake stronger not knowing the consequences, and I have seen many failed engines for just this issue alone when someone gets into that situation where they need that engine brake on high, and end up at 1700, 1800, 1900+ rpm,.. and boom!,.. engine destroy itself for no apparent reason. MOST people keep their rpm in check during engine braking, and that is great, but it is that one time that it will save your arsse, or prevent that brake fade going down 4'th july, donnar, or grapevine, or some other mountain,.. but what good is this protection/system if someone has jacked it up to the point of causing engine failure at the point where it may be needed the most?--- Another one of the more common things I see people who do not know how these engines work, end up destroying them.


* The egr actuator logic has not been properly turned off. Blocking codes were added to the program to prevent the alarms from showing in the dash of the truck were used to mask this error/descrepency.

* The EGR delta-P sensor logic was also not properly turned off. Same thing, again, blocking codes were added to the program to prevent the alarms from showing in the dash of the truck were used to mask this error/descrepency.

* The DPF Doser injector logic was also not properly turned off. Same thing, again, blocking codes were added to the program to prevent the alarms showing in the dash of the truck were used to mask this error/descrepency.



* A valid attempt to run the engine in its factory non-egr operating mode was made. This is far better than a lot of bad programming that I have seen, ... However ... The method that was used (simply fooling the egr temp sensor), has been shown to not be 100% reliable on older trucks that may have other less obvious issues. It has been seen that sometimes, when using only this method, it can jump out of this mode, causing instability when the engine is in extreme weather sometimes, when sensors are reading wrong, or other factors. <- This method is certainly out of date, and there is definitely a need for more improved methods to be used/applied. Since this is the case, It would not surprise me if this may be part of the issue you are seeing now, but it also may not be. - Only testing the engine live and observing what operating mode it is staying in while it is acting up would reveal if this is part of the issue or not.

* All derates and shutdowns are still active for the engine. <- Some ppl would say that this is ok to leave all this stuff on, but now you are experiencing sudden boost pressure and other strange things, likely with no codes in the enigne to tell you what has happened. For all you know, the derate for exhaust temp, CAC leak detection, Turbo derates for a turbo that may be getting weak, and about a dozen other reasons of sudden unexplained power losses may be occurring. since there have been many codes blocked from being allowed to show up, this could make the thing very difficult to troubleshoot, and there is always the risk of thiat engine laying down on you for one of these now somewhat masked problems. <- Bad practice to leave all that stuff on and the emissions and other systems of the truck suppressed/unable to tell you what is wrong. - This should be corrected, as the only derates and/or shutdowns that should be still active, should only be for oil and/or coolant, nothing else. This is another sticky-point that could be causing your strange boost-loss problems, but only thorough testing of the engine and its operating states would reveal it. Though some would disagree, I own a truck too, and As far as I am concerned, it is a mistake to turn off all those system yet leave these derates and shutdowns all on making for an unpredictable condition, or engine leaving you on the side of the road somewhere because it refuses to run.

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That program certainly needs to be updated and repaired. That would be your first move, and after that, you can then start looking at hardware issues that may have caused things to suddenly change, as like you said, at one point it seemed to run fairly ok. <- there is also room for improvements to how the engine runs and its efficiency if things are done in the right ways, as the person who did your 'de^lete' program did not apply any of them at all. They left the derates power and other tables in the ecm from the factory, and this is not optimal when there is no more egr gas being sent into the intake.


You also need to ensure it is not one of those still active derates getting it. You need to pressurize the CAC, and then the whole enigne to ensure there are no air leaks between the intake of the turbo and the exhaust of the turbo. use blocking plates and pressurize it up to 30 psi and check every gasket, seal, component, your egr block-plates that were installed, that CAC unit, and everything else.

Programming aside, You should also adjust the overhead valves and do an injector leak test, etc. to ensure you do not have other issues, and HOPE LIKE HELL you have not cracked the head between the valve seats because of the engine brake being set up too high.