ISX cm2250 emissions help needed

[dslmchnc]

I have a 2012 389 peterbilt with a 485 isx cm2250 cummins. This truck has been an albatross from the day we bought it at the beginning of this year. We purchased it used and it had scr fault codes in it after only one day of running. We eventually found that the scr unit itself had split the case from having a broken hold down strap. The catalyst was full of dirt and debris and needed to be repaired. There is a machine shop locally that does all of our dpf cleaning for us and was able to clean it and repair it. after that was all said and done, we ran the truck without issue for about 3 months. Somewhere between then and about 2 months ago the truck started using coolant pretty heavily. The driver never notified us of this issue and kept adding coolant himself. we finally caught wind of it and check the egr cooler, upon removal of the outlet hose we found that the cooler had ruptured. We replaced the cooler and the coolant loss ended. About two weeks ago now the truck was in a derate and had dpf differential pressure fault codes, i believe 3583 was the code. i checked the tubes for blockage and correct orientation, found that ok. I observed that the outlet dpf sensing port on the differential pressure sensor had moisture in it and the sensor itself had wtaer in it. I replaced the sensor, made sure the tubes we clear and ran a parked regen. The truck passed the regen and seemed ok. I sent it out for a test drive and as soon as my driver got 10 mins into it the regen required light came on. the truck returned and i found the retun voltage from the differential pressure sensor was below cummins specification. i watched the data while i wiggled the plug and found the data erratic during movement. i replace the shell of the connector and thesilicone boots, along with the pins. I initiated another parked regen and it passed. Again i sent the truck for a test drive and agin smae dpf regen request light came on. this time when the truck returned i had fault coded 3375 and 3376. i ran anothe rparked regen and ran a restriction test which the truck failed. I removed the doc and dpf to have them cleaned. both items passed the flow test that they perform after a stage 2 cleaning. i reinstalled both items and reset the dpf and ran it through a parked regen. same problem after test drive, 3376 and 3375. The dpf again faled the on truck restriction test. I disconnected the exhaust outlet and ran a snap test and found no smoke exiting the engine. i replaced the dpf with a cummins reman. i also removed the hydrocarbon doser and cleaned that, along with cleaning the imap sensor, cleaning the egr differential ports and sensor, the exhaust back pressure sensor, and even replaced the exhaust pressure sensor when i noticed that in a KOEO condition the barometric reading, which is an absolute pressure sensor as well as the exhaust back pressure sensor, dissagreed on preessure. I reset the dpf again, and sent the truck into service. the truck got about 2 hours into its run and the regen light came on. The driver pulled over and initiated a parked regen. We sent another truck up to it to take its trailer, and brought the truck to cummins because it was only 10 mins down the road. they looked at it and determined that the hydrocarbon doser was malfunctioning and replaced it. we took the truck back, picked up a new trailer, loaded the trailer, and got about 4 hours total use before the regen light came back on. the driver initiated another parked regen and was able to get it back to the yard. it snowed here saturday and now im tired from plowing and chasing our sanders around all weekend, and am at a wits end. I need help. one thing that i notived that seemed strange was that the exhaust gas pressure during the parked regen was about 163 inhg during a parked regen. it seemed high to me. this truck has 215xxx miles and over 10600 hours, i realize that is a lot. we have a 2016 t700 kw with 8500 hours and 250xxx miles. please reply with any advice, any help is appreciated. DSLMCHNC

[T680]

Not sure what u are looking for,to me u are on top of the troubles, IMO won't lessen

Anyway I'm the least one to give any advice

Just looking at those 2 trucks hours, I'm happier still that I bought me a Tripac when I got my truck

I got the last ecm printout at alround 240k miles and ECM time is 4446 Hours, so basically, yes, Apu's are expensive but for those that can have an extra 450lbs hanging in there is worth it.....every penny...

[dslmchnc]

(12-19-2016 )T680 Wrote:  Not sure what u are looking for,to me u are on top of the troubles, IMO won't lessen

Anyway I'm the least one to give any advice

Just looking at those 2 trucks hours, I'm happier still that I bought me a Tripac when I got my truck

I got the last ecm printout at alround 240k miles and ECM time is 4446 Hours, so basically, yes, Apu's are expensive but for those that can have an extra 450lbs hanging in there is worth it.....every penny...

Thanks for the bump, i am still baffled by this. i am going crazy here. i would appreciate it if RAWZE would chime in haha!

[Rawze]

3375 - DPF regen too frequent.

3376 - DPF Incomplete regen.


3375 and 3376 are both codes for the DPF being clogged, but they can also occur due to other exhaust restrictions too.

* The SCR can clogged will trigger these same alarms. You said someone "fixed" the SCR can instead of replacing it. What does the face of it look like now, after several months? -- Those SCR cans, even if they have a little bit of soot, etc. in the face or in them will cause all kinds of exhaust restrictions. -- Since there is no sensor for this,.. It throws DPF alarms, because the DPF differential press sensor ALSO reports the pressure and/or restrictions along with the difference pressure.

* You claimed it had a bad EGR cooler,.. -- THAT ALONE! can and will cause the DOC to go bad,.. the DPF to possibly go bad,.. AND DEFINITELY the SCR can to go bad and get restricted!.


From what you posted, I see several mistakes...

* Trying to repair the SCR can after it got contaminated instead of replacing it. -- Maybe you got away with it for a while,.. but it certainly sounds like it may have now caught up to the fact.

* Ignoring the fact that an EGR cooler failure CAN AND WILL destroy those components in a hurry, and NOT replacing them, but instead, trying to nurse them back to life to save a few bucks. -- No harm in trying, but then don't go around wondering why you are having repeating problems.

* You never mentioned anything about the decomp tube, or if it has been checked for a "Volcano" --> http://rawze.com/forums/showthread.php?t...07#pid1807

* You never mentioned the state of the engine, other than to say it isn't making a lot of soot. (leaky injecotr(s) or rail, intake and/or egr leaks or restrictions, EGR valve health, etc.


* you never mentioned what the regen history looked like, nor what the numbers were after a regen.

* the truck has an INSANELY HIGH amount of idle time on it compared to the mileage. This is bad for the whole emissions system on those trucks, and requires more frequent preventative maintenance and regular forced regen cycles,.. this ultimately shorten the life of all those components anyways.


---

I do not have engine E.S.P. -- but it sounds like you are running in circles and getting not much of anywhere, when you should take a step back and look at the bigger picture(s).

[dslmchnc]

Thanks for the input. A few things to discuss, i forgot to mention that after it came back from cummins, when they replaced the aftertreatment injector, it ran for a few hours before it broke down again. when i got to it yesterday morning, the active fault codes that it had were, 3375 and 2754. the 3376 never came back after the aftertreatment injector was replaced by cummins. it also logged 2639 3 times in day, and also 1921 once.

Does the ecm compare barometric pressure to the dpf outlet pressure to determine exhaust restriction? after i replaced the dpf my restriction code accross the dpf changed to an inlet restriction code which i never had before. it seems that the dpf was in fact bad and the pressure problem that i have now is a general exhaust restriction flow issue. the dpf inlet pressure too high could also be a restriction of flow across the scr because it is down stream and would make the computer think that it is a dpf restriction. the differential pressure is ok, but the scr being blocked could be like holding your hand over the exhaust, and without pressure sensors across it to give a differential pressure reading, the ecm assumes that it is a dpf restriction issue.

BUT, is there really and exhaust outlet flow issue or is there an inlet/egr flow issue that the ecm isnt seeing, and just assuming that it is an echaust flow restriction?


Cummins said that they suspect the doc of being an issue after they changed the aftertreatment injector. i am not sure why they think that, i cant get an answer about that from them. if it was a temp issue i could believe that it was an ambient temp issue. it was very cold in Maine the day they had it, like -10.

this truck was bought from a local dealer that got 6 of this same truck in a group buy at the end of last year. the identical twin to this truck was bought by another company in this area and they had the same scr issues that we had when they put it into service. the local machine shop has done this scr cleaning many times and apparently its pretty sucessful. the dealer we bought this truck from payed for the repairs as a pseudo warranty. as far as i know the other truck has been fine since they cleaned the scr unit. at first i was sceptical of the cleaning idea. i had never heard of that as a possibility. i thought it was a non-servicable item. this repair has lasted since february, only time will tell if this is actually the issue.



as for the driver who didnt tell us about the coolant loss, he has been let go due to other reasons. i am very aware of the damage that ANY use of a truck with coolant or any other foreign material entering the exhaust is very detrimental to the health of the aftertreatment system. i was unaware of htis issue and since then the drivers have no access to engine fluids and must report any needs to us.


after reading you post response last night, which i greatly appreciate, i removed the scr dosing injector this morning and checked the decompostition tube, i am happy to report that it is clean and free of obstructions. i am starting to lean towards the scr being faulty bacause there are yellow stains around the joints after the injector and the scr, which could be caused by excessive pressure due to excessive restriction. instead of it being soot free gas after the dpf, it is gas now mixed with urea and leaves a trace better that just exhaust.



As for the state of the engine, i have checked for exhaust leaks, intake leaks, the egr valve is clean and functioning properly. the fuel system leakage test has passed within spec and the high pressure, and low pressure fuel systems have no leaks. the fuel filters are regularly changed, and the air filters are also regularly changed.


Last night i removes the egr pipes that link the cooler to the valve and the crossover pipe to the intake and the charge air cooler pipe to the intake. all pipea and passages are clean with a little hint of soot on them. i have seen many egr differential pressure sensors changed beacause of egr issues, when the culprit was actually a clogged cooler, but more commonly the sensing ports were clogged. this egr system is clear from restrictions and so is the intake manifold. i have a bore scope that i ran into the intake and didnt see any issues.

I realize that this engine has very high hours, but the price was right, and the truck fit our needs at the time. i will attach the ten most recent regen files. i really appreciate any input. i think my next coarse of action is to change the intake manifold pessure sensor, egr differentail pressure, egr outlet pressure sensor, and the barometric pressure sensor to rule out any malfunctioning in range sensor issues.

if that doesnt fix it it think the next step will be to remove the scr cata;lyst and replace it. i underwstarnd that i will probably h ave to have it recalibrated afterwards due to updates and i have heard of total replacement kits from cummins that remove a npx sensor. do you know anything about that? not an scr delete, but when they replace the scr unit, other changes must be made i have heard, but maybe thats only on midrange. i dont know.


I dont have any factory trainging on any specicific manufacturer, but the isx cummins are a real problem. we have some newer trucks taht are ok. we also have some egr only engines that are fantastic. i love cummins engine, but the paccar mx-13 engines that we run are better. the only issue with them is the power. i wish they would design a 15 liter engine. we run 100,000 lbs and have been buying all 600 hp isxs lately. the 600s seem to have fewr issues. also the 550 high torques we have are ok.

i would like to take a minute to thanky you personally RAWZE for creating a place where diesel mechanics can get together and help each other out with issues that the dealerships either cant figure out or wont. i look forward to contributing to this forum, both financially and maybe to share some of my knowledge about other things as well. i have worked on many different truck with many different problems. i also work with some very seasoned older mechanics that have TONS of knowledge about older trucks. i would happily answer any questions that i can. feel free to pm me, that goes for anyone.

You are provinding a great service. Thank you very much!
dslmchnc

[dslmchnc]

(12-19-2016 )Rawze Wrote:  3375 - DPF regen too frequent.

3376 - DPF Incomplete regen.


3375 and 3376 are both codes for the DPF being clogged, but they can also occur due to other exhaust restrictions too.

* The SCR can clogged will trigger these same alarms. You said someone "fixed" the SCR can instead of replacing it. What does the face of it look like now, after several months? -- Those SCR cans, even if they have a little bit of soot, etc. in the face or in them will cause all kinds of exhaust restrictions. -- Since there is no sensor for this,.. It throws DPF alarms, because the DPF differential press sensor ALSO reports the pressure and/or restrictions along with the difference pressure.

* You claimed it had a bad EGR cooler,.. -- THAT ALONE! can and will cause the DOC to go bad,.. the DPF to possibly go bad,.. AND DEFINITELY the SCR can to go bad and get restricted!.


From what you posted, I see several mistakes...

* Trying to repair the SCR can after it got contaminated instead of replacing it. -- Maybe you got away with it for a while,.. but it certainly sounds like it may have now caught up to the fact.

* Ignoring the fact that an EGR cooler failure CAN AND WILL destroy those components in a hurry, and NOT replacing them, but instead, trying to nurse them back to life to save a few bucks. -- No harm in trying, but then don't go around wondering why you are having repeating problems.

* You never mentioned anything about the decomp tube, or if it has been checked for a "Volcano" --> http://rawze.com/forums/showthread.php?t...07#pid1807

* You never mentioned the state of the engine, other than to say it isn't making a lot of soot. (leaky injecotr(s) or rail, intake and/or egr leaks or restrictions, EGR valve health, etc.


* you never mentioned what the regen history looked like, nor what the numbers were after a regen.

* the truck has an INSANELY HIGH amount of idle time on it compared to the mileage. This is bad for the whole emissions system on those trucks, and requires more frequent preventative maintenance and regular forced regen cycles,.. this ultimately shorten the life of all those components anyways.


---

I do not have engine E.S.P. -- but it sounds like you are running in circles and getting not much of anywhere, when you should take a step back and look at the bigger picture(s).

[dslmchnc]

I just remove the inlet to the screen and from what I can see the face of it looks pretty clear. There is one spot about the size of the palm of your hand with some black staining on it. It is hard to get an exact clear look at it because of the inlet screen that it has going into it.

[simon999]

You have 9.7 inhg. Good healthy regen is close to 1inhg. Looks like bad doc, dpf, scr needs to be cleaned and check flow. If flow test will fail replace them.

[dslmchnc]

Dpf is a cummins certified reman. Doc has been cleaned.