I'm in aftertreatment homeschool

[Punchy]

2012 Cascadia daycab with Cummins ISX, popping codes for several months related to the DPF/DEF/SCR aftertreatment system. I don't have Insite at this time, but a heavy duty code reader that gives much info, yet this particular device can't do anything about the problem per se. One code that visits from time to time is 1569/31, which is surely recognized instantly by many.

A breakdown of the canisters and cleaning of filters is a few weeks away as schedule permits. Until then, and up until the moment I write this, we've replaced all temp sensors (the existing temp #3 outlet on what I believe is the SCR can, was actually broken off (disintegrated?) in there when swapped out). The proble still attached to the wire was maybe 5 mm. Some issues disappeared after these replacements.

I've always heard, "don't be a parts swapper just to swap". There's truth to that... I simply want to know what was done to this truck and I don't know/trust the previous owner like that. So, I'ma swap as I play amateur detective. I want to leave this truck better than I found it.

The DEF doser was replaced, and the truck improved still more. However, regens are still unsatisfactory or need to be forced. I suspect that inside this small section of exhaust, right behind the turbo, is clogged or caked over. The V-clamps were nearly welded on. Got those off, and the downside of that exhaust section is able to be loosened from the following pipe which descends to the cans. But, the section connected to the turbo is going to need a chisel to break it loose. They look glued together.

And that brings us to date: The plan is to remove that section which holds the doser and the upstream/inlet NOx sensor there, and see if it's soot-covered up where the new doser needs to be misting.

Attached find a rough diagram of this unit's set-up. Rough = I know I'm way off. I've found that Cummins' diagrams are woefully incomplete and sometimes straight-up blurry, I try to zoom in and it's like 20/100 vision. I'd like help to finetune this over time and hopefully it'll help somebody.

I'm taking all notes.

[Rawze]

I removed your picture/drawing. It is bad information and incorrect.

2012 ISX with SCR is a CM2250 model engine ...

Register your engine ser# on quickserv.com and you can get any drawings and part#'s for the engine and its aftertreatment systems. Its free.


As far as the rest of your post goes.. you were not very clear on what the issue is besides replacing a sensor that was bad.

Also, throw that garbage half-arssed reader in the trash and get an actual Inline-6 adapter off amazon or somewhere (about $300 bucks or less), and the Insite software (Insite can be had for free off the interwebs in the right places). This way you can properly troubleshoot it and do other needed tests to the engine/ aft-systems if necessary.

Some actual history on the truck/engine?.

The Actual cummins fault codes that keep coming up?

What does the regen history look like in Insite?. maybe a post screen shot of it?.

How much oil and/or coolant does the engine consume over time between oil changes?.

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BTW: there are 2 Doser injectors in the system. They are...

1#. The 'DPF Doser' (located right behind the turbocharger), and it sprays diesel fuel into the exhaust for rapidly heating the DPF element during a regen cycle.

2#. The 'DEF Doser' injector (located in the exhaust just before the SCR element) that sprays DEF fluid into the exhaust to help convert NOx gasses into CO2 gasses.
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When is the last time the DPF Doser injector ( the one right behind the turbo ) was cleaned or replaced?. By the way, if the Doser injector pipe behind the turbo does not want to come loose after removing its clamps like you mentioned, .. then smack it with a 3-lb hammer. The joint for it is just rusted together is all... and NO, it is NOT the DEF doser like your bad drawing suggested,.. that one is the DPF Doser.

- The DEF Doser by the way, is down under the truck, located in the decomp tube between the DPF element and the SCR element. And that decomp tube is known for getting a 'Volcano' built up in it if that DEF doser is leaking. Something else to check for while you are at it >ref: http://rawze.com/forums/showthread.php?t...07#pid1807


When is the last time an actual and thorough EGR tune-up was done?... replacing the IMAP sensor, Exhaust pressure sensor (and cleaning its circuit out), The EGR Delta-P sensor (and its circuit), the EGR valve checked/cleaned and all the EGR piping cleaned out thoroughly?... - THE DPF does not make the excess soot... THE ENGINE DOES!.

When was the last time the DPF element and the DOC element were removed and taken to be properly baked, de-ashed, flow testes etc. as a stealers$hit?. This is due about every 3-4 years max for these engine, as the engine itself, and its regen process, is unable to fully clean the elements properly on its own very well any ways. .. and do you have pictures of their faced when they came off?.

Post pictures of the faces of the DOC and DPF whenever you remove them to get some opinions on how bad that have actually gotten and what kinds of buildup might be on their faces... so that the source of the issues can be identified.

[Punchy]

I've been running this truck for just about two years. It was used to deliver dry and reefer groceries from manufacture up until 2020 as far as I know. I'll dig into whatever fleet mechanic notes I can find from them.

I have a list of the codes I've seen since May when the truck began running differently, when I started scanning. Worse fuel consumption, a "hitching" at times during acceleration, rougher idling. I do remember seeing the 102/16 and 102/18, alongside the 1569/31. Those three alternate in and out in recent weeks. I got rid of those 102s before by doing my PM earlier than usual: Oil and filter, fuel filter and fuel-water separator. But they've returned in the last two months, as the aftertreatment system has developed more issues. Those three are the usual suspects I've seen. I'll list the others that came and went, when I get back to my notebook.

I haven't seen it lose coolant. I drained and replaced that when the topside/turbo DPF doser was switched, and the level still seems okay. Oil consumption starts at around 10K after oil change. Then it's downhill and I'm adding a quart maybe per 1,000 miles after that. I was changing oil at 15,000 to 18,000 when I got the first truck (also Cummins). I do it around 12,000 now.

EGR-related tune-up? None by me, and no mechanic has ever suggested performing that procedure to me in the five or so years I've had my own trucks and started learning to maintain and repair them. I've done things like air bags, replacing fittings elsewhere on the air system/tanks. Oil and filter and fuel filter changes, keeping tires inflated with a gladhand-fitted air hose. Minor electrical stuff like fuses and headlight wiring. Replacing the starter, air dryer cartridge, AD-IS unit, crankcase filter and sensor, crankshaft sensor, IMAP sensor. Other what I consider, basic things that most anyone could do.

Everything I know mechanically is related to issues our trucks have, that I then researched best I could while gathering tools for such issues, and finally I did what I needed to do to keep it going. It's worked out almost every time although I need a lot longer than a shop or a knowledgeable wrench-turner would take... but yeah, kinda slapdash. Wish I'd come across your forum a few years ago.

The only EGR item I swapped on this truck is the sensor there. Your playlist videos alerted me to the actual components such as EGR valve and cooler. I'm on the case to remove, inspect and clean. Other drivers with their own trucks don't know and don't care to discuss this stuff with me; they just pass their trucks to the shops. I have a precious few in my contact list that do know and will talk, but these usually have DD or CAT and can mostly give me principles, not real info on a Cummins. Of course the mechanics (again with a few exceptions) act as if I'm bothering them, or taking money out of their pocket, when I approach with my many questions.

I will check for the DEF doser you say is deeper in the system. The DPF doser which I've apparently mislabeled, and was changed this month, even the parts guys and dealership don't call it the right name. How do I know as much as most of them do, and I just started touching this stuff some weeks ago? As far as I know, the DPF doser has never been changed until I saw someone on YouTube discuss it, which motivated me to open all that stuff up and change it myself. I asked a few shop managers about the symptoms and codes, and every time I got "New turbo" and/or "Take the entire system apart and bake before anything." Is that correct? We're stepping up to that second one shortly (will definitely show pictures) but the first suggestion seems kneejerk and predatory. Again, never heard EGR mentioned and I reach out to a lot of people, sometimes out of my time zone in shops and dealers I'll phone randomly just to pick some stranger's brain.

The photos here are of the old snapped-off temp probe I removed, "temp 3", and of the flexible metal coolant hose to the DPF doser, inlet I'm guessing, next to the new hose. I had no idea what I was looking at, at first, didn't know that those two nuts are separate components because everything was so seized up. You see I chewed the hose nut up with a pipe wrench and still could barely get a twist. I drained the coolant, detached the other end of that hose from the block, and then twisted loose the entire old hose, then unscrewed the entire doser (after unplugging and after unscrewing the fuel hose). Because the outlet coolant hose there, its two nuts are seized as well. Yes, it's been fun.

I'll bring someone in with proper software to plug in ASAP.





   

[Rawze]

== YES you need to do a full EGR tune-up on it, and not just replace the IMAP once in a while. Should be done about once a year actually, and more thoroughly every 2-4 years. Watch my videos on it .. and adapt the ideas for your particular engine model.


Looks like you also need to start investing in proper tools instead of "pipe wrenches". here is what is needed for those pipe fittings if they have been over-torqued by dsome idiot in the past...
ref: https://amzn.to/3M7oTYC

And here are a lot of other tools and things that I recommend .. and no, it is not because I get sponsiorshi$ts on it.. it is legit stuffs that I either own and use a lot, or have/would use on my own truck...
https://www.amazon.com/shop/rawzescollec...ons_list_d

And a good set of impact/ hardened 6-point metric sockets that will not strip bolts, and a very good set of 6-point wrenches. - Never use the cheaper, or typical garbage depot, 12-point sockets on a commercial engine!.. Throw them away and buy better tools!>