DOC Catalyst Efficiency Numbers

[MPDiagnostics]

Got a 2014 ISX CM2350, 700,000ish miles.
- DPF replaced recently!
- Don't know when EGR tuneup was last done but at the given moment the truck is constantly asking for regens. No exhaust leaks, but haven't thoroughly checked CAC system for leaks. I was looking around Insite to see what I could find and wondered about the DOC efficiency numbers. On other trucks I often find 0.95 across the board, but on a few I'm starting to see similar to this

   

So I'm wondering if these number are getting high. Can't seem to find specs for this either on quick serve or in service manual.

I feel like the DOC is getting plugged but not quite sure. If it is, can this be sent to a shop and get cleaned out??

Help me out if you can cuz I haven't ventured here yet.

[Lonestar10]

numbers are ok but theres a reason its regening to often there is something intruding into the system like oil from valve stems or from the turbo you need to pull the exhaust off the back of the turbo start it then stick a peice of paper infront of the exhaust stream and see if there is any liquids or anything that gets shot onto the paper then work backwards from there to find out where it is.

[MPDiagnostics]

Thanks for the input!!

[Rawze]

also do a thorough egr tune-up including cleaning or replacing the doser injector behind the turbo and IMAP sensor.

The DOC and DPF can be pulled off and sent to a stealers$it to have baked, cleaned, de-ashed, and flow tested for a few hundred bucks. - If you have this done, take pics of their faces before cleaning for some opinions on any buildup and what it might be from.

[MPDiagnostics]

Do you guys know what the numbers mean/say about the filter currently? And what numbers would be too high?

[Rawze]

(10-16-2019 )MPDiagnostics Wrote:  Do you guys know what the numbers mean/say about the filter currently? And what numbers would be too high?

post the numbers of the far right column (of after-treatment history). That is what I usually look at. - Anything much more than about 3.0 inhg and you likely have problems.

[MPDiagnostics]

I'm not in the Aftertreatment History Tab here. This is under DOC catalyst efficiency. Its as far right as it goes.

[Rawze]

According to some documents I have on the after-treatment system, if the system thinks the "Estimated SCR Catalyst efficiency" is too low, it will do additional regen because it thinks the decomp tube might be partially clogged up/dirty.

Pull the DOC and DPF, have them cleaned, baked, de-ashed, and flow tested. Do an EGR tune-up on the engine, and Check the decamp tube for the all too familiar "Volcano" scenario mentioned here...
http://rawze.com/forums/showthread.php?t...07#pid1807

clean the DEF screen and injector while your at it.

As well, like has been mentioned, take pics of the faces of the DOC and DPF and post them here for some opinions on what may be built up on their faces.

Also, like mentioned, check for white smoke or other liquid spatters when starting up the engine with a piece of paper held right behind the turbo/doser pipe and the exhaust pulled loose.

[Pete1990]

I'm currently fighting this issue with my truck. Question is How much oil are you adding? 2014 was known for carbon packing and it affects the DPF system very badly.. My DPF and DOC are messed up bad from the Blow by. Cummins says something like 1 gallon every 3300 is safe but its really not.. That oil has to go somewhere which would be the DPF system. I regen everyday because of carbon packing.