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+--- Thread: Isx cm2250 exhaust gas pressure (/showthread.php?tid=1732)
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RE: Isx cm2250 exhaust gas pressure - Rawze - 06-09-2017
(06-08-2017 )zyNoT Wrote: I'm actually having the same problem. Chuffing turbo during regen. I had a code once for exhaust gas pressure but it went away and has not come back. DPF is new installed by Cummins. EGR diff pressure sensor is new, IMAP is new. I'm not sure what else it could be. It's doing regens twice a day or more.
What typically causes it is the ECM is demanding excess positive pressure in the exhaust manifold from the turbo usually to force more EGR gas through the egr circuits. Anything that can slow down the turbo, like exhaust restriction can cause it, or if it simply gets bad feedback from a sensor. Some guys have discovered that relieving some of the pressure at the clean air side by opening a fitting or CAC joint slightly stops the "chuffing". This is no solution at all, but is a solid indicator that it is an excess in demand by the ECM on the exhaust, egr, or manifold pressure side of things that is the cause.
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Most common rerasons is bad or dirty sensors like the IMAP, DPF Delta-P, EGR Delta-P, mis-reading Exhaust gas pressure sensor, dirty crossover tubes for either of the Delta-P sensors, etc. but if you have eliminated all those...
Excess back-pressure in the exhaust system will cause it to "chuff" too. Just because the DPF is new does not mean that it will pass a flow test. It can also be the SCR can clogging up, the DOC can clogging up, the decomp tube may have excess buildup, or even that brand new DPF can. -- It can also be the EGR cooler itself loosing thermal efficiency due to soot and carbon buildup in it, or the EGR valve sticking.
A leaky exhaust manifold or egr circuit can cause it too.
Incorrect program in the engine can do it too from someone trying to turn up the HP. there have also been a lot of calibration updates by cummins for these types of problems, so make sure the calibration is up t date before chasing too many ghosts..
The NOx sensors are only good for about 250k miles before they read bad. Sometimes they will throw a fault, sometimes not but when they go bad, the ECM thinks NOx levels are higher that=n they should be and it starts demanding more and more EGR gas pressure to lower the NOx. This can cause this type of chuffing issue too.
Could be something stupid like a dirty air filter too.
Those 2250 and 22350 are notorious for turbo chuff, so much so that there is even a manager in the ECM to help control/reduce it but it obviously does not help by much. Even on a fairly healthy system, they will occasionally do it, and it is definitely bad for the turbo.
What does the regen history look like?
Has anyone taken a look inside the Decomp tube for the infamous "Volcano"? -- http://rawze.com/forums/showthread.php?tid=283&pid=1807#pid1807
Has anyone thoroughly cleaned out the crossover tubes for the DPF Delta-P sensor and checked the rubber joints for cracking? -- Cleaned out EGR Delta-P crossover block? -- Good places to start.
Anyone inspected the face of the SCR can,? -- The DOC can?
Flow tested them?
How old is the engine out NOx sensor?
... here is more on this subject and what has been seen... http://rawze.com/forums/showthread.php?tid=2506&pid=22458#pid22458
RE: Isx cm2250 exhaust gas pressure - orionlover69 - 06-11-2017
(05-03-2017 )dslmchnc Wrote: This truck is also making a chuffing noise during a parked Regen.
Don't know. According to Cummins this is normal. I know exactly what you are talking about. Something to do with the geometry of the turbo causes unswallowed pressure to pop out every once in a while. I've investigated the matter my self for some time but no conclusion as of yet. It could possibly be back pressure as stated below but even fresh DOC and DPFs have not changed that chuffing. Or turbo cough.
RE: Isx cm2250 exhaust gas pressure - Rawze - 01-17-2018
(06-11-2017 )orionlover69 Wrote:(05-03-2017 )dslmchnc Wrote: This truck is also making a chuffing noise during a parked Regen.
Don't know. According to Cummins this is normal. I know exactly what you are talking about. Something to do with the geometry of the turbo causes unswallowed pressure to pop out every once in a while. I've investigated the matter my self for some time but no conclusion as of yet. It could possibly be back pressure as stated below but even fresh DOC and DPFs have not changed that chuffing. Or turbo cough.
a possible solution...
http://rawze.com/forums/showthread.php?tid=2506&pid=22458#pid22458