ISB 6.7 Too Much Soot Guidance

[Craig]

Hello All, long time lurker, trying to learn as much as I can but I'm stuck and was hoping to gain some insight. I've been trying to help a friend with his rollback but I'm at the end of my knowledge base. Here's the details and what we've tried so far.

2015 Freightliner Rollback with an ISB 6.7
Issues:
Dash lights up like a Christmas tree with MIL, Regen and Stop lights.

What we've tried:
Removed the aftertreatment filter and pressure washed it out.
Removed the EGR Valve and cleaned it up.
Connected Insite and retrieved several codes: 1922, 3375, 3383, 2639 and 1921.
We cleared the codes and did a DPF reset.
Did a manual regen, this took about an hour and twenty minutes to complete.
Then took it out for a drive and everything seemed to be fine.
The very next day, the dash is lit up again and it goes into limp mode :(.

As I've read many times on the forum per Rawze, the filter isn't making any soot. So I was wondering if anyone had any ideas where we should start to try and figure out why this thing is creating so much soot.

Thanks for any insight you guys might have!

Craig

I have several insite files if that would help. I'd really like to learn as much as I can about this so if he needs help I can actually contribute.

[Rawze]

One of the biggest mistakes people tend to do to them is to take a liquid to the DPF/DOC elements. If you washed it out then this was a big no-no. It is now highly likely that about half or more the precious metals that make the DPF operate correctly are now stripped away and it is more than likely doomed. AND if you took hard pressure to it at all with that wand, you also likely destroyed many if not most the cavities that were actually supposed to be blocked off at the back end of it 50% of the element (every other hole) is NOT supposed to be pass-thru, but blocked at the far end. - The thing likely will not regen properly any more .. is struggling just to keep up and ignite the fuel properly with half its metals gone ... Not sure about an isb but on the ISX, it is only supposed to take 40 minutes or so to burn off. If it took 1.5 hours, I would say something is weak at this point or failing.


Next would be to going thru the whole intake and EGR system, not just the egr valve. Things like the imap sensor needs replacing, and other sensors like Delta-P, other piping and circuits, etc.

NEXT you did not mention the DOC element. It should have been pulled out and taken to have baked, etc.. too. The DOC and DPF elements BOTH. - they should have been taken to a stealers#it with the proper machinery and baked, de-ashed, and then flow tested properly instead of trying to red-neck the whole situation. Trying to pressure wash it like those collections of dumbarsses on social medai and you-tube creates as many problems as it hopes to solve.


What about the Delta-P sensor and crossover lines for the dpf while your at it?


Did anyone take pics of the faces of the elements before trying to clean them? to see what exactly was on the faces as buildup? -- sure, some soot but combined with oil residue? coolant residue? --- Was the coating even or more dense in areas indicating it might be cracked internally? -- etc.etc.etc. - Posting pics on here often can tell a whole lot towards issues someone might be having.

What about replacing the Doser injector if it is old?. they can clog up and/or go bad and cause some issues for not regen properly too.


Sounds to me like a very strong possibility that it now needs a new DPF element at the very least.

The DOC element needs to be taken off and done properly too (baked along with DPF element, etc.) ... or did it get ruined with that water-gun as well?

The rest of the engine systems, egr sesors, exhaust sensors and piping, Delta-P sensors and piping, doser injector, etc.. dealt with properly instead of only doing the valve.

ppl gotta keep in mind that when the truck and its engine were new, those system likely worked very well without any real issues. What goes down hill is that the egr system .. the whole system and its sensors... getting sooty as all hell ove time including the piping for all of it, the EGR cooler, etc.etc.etc. over time. The doser injector gets clogged over time as well and then those emissions cans under the truck suffer the fate of all the neglect.

Those engine sensors and systems need regular maintenance LONG BEFORE ANY CEL LIGHTS whatsoever start to come on. When ppl wait till they get regen codes and issues then it is far too late and the entire systems are in dire neglect at that point.

This also comes to mind: Did anyone bother to put a bypass oil filtration system on it the day it got purchased to keep the soot out of the oil system so that it did not get carbon packed?---Likely not. Soot buildup in the oil is the engine killer and the factory filter is not going to keep it out well enough on its own for squat.


Anyone bother to pressurize the entire intake and exhaust systems to look for boost and exhaust leaks?-- those emissions system cannot handle problems/leaks like this.

What about the EGR cooler?--- How old is that thing? and is it in need of removing and cleaning all the carbon and soot buildup out of it too?. they get clogged up and inefficient and this needs to be done to them when they get old... or if they suffer more than normal condensation intrusion due to environment, etc. they will clog up and get inefficient as well.

These are the things that come to mind on a whim... the beer has partially taken over.

[hookliftpete]

Second everything rawze said, he knows it through and through. However, being that your operation is lots of stop and go and extended idle, definitely worth your while to look at a demand. I run the big brother to your engine (isc) on a hook lift truck. Demandate saved me. These engines reach a certain point where the after treatment cannot work as intended and it’s a never ending loop of pain. Demandate brought my mileage up 1mpg, cleaner oil, and better response out of the engine. This is stock still, nothing big boss or other baloney. Stock Cummins tune.

[tree98]

What's the best way to clean out an EGR cooler?

[Craig]

Thanks so much for you input, I will have to take your response back and try and get the answers. Sounds like it's going to be expensive, however, they just bought a new truck and I think you may have saved it from the same fate as this one. I'm going up there this weekend so I'll get some answers and try to create a game plan to go through all the systems you mentioned. Or, after reading your response, he may just want to demandate it because of cost. I'm trying to get him to fix it for obvious reasons, yearly inspections and such but didn't really know where to start but now I think we have a jumping off point for sure, can't thank you guys enough :).

[hhow55]

(01-12-2021 )tree98 Wrote:  What's the best way to clean out an EGR cooler?

http://www.trucktrend.com/how-to/parts-a...-solutions

Maybe this help's

[Rawze]

(01-13-2021 )hhow55 Wrote:  

(01-12-2021 )tree98 Wrote:  What's the best way to clean out an EGR cooler?

http://www.trucktrend.com/how-to/parts-a...-solutions

Maybe this help's

I have found that flushing one with charcoal lighter fluid to remove oils, soot, and carbon buildup really well followed by a soak with degreaser, water, then acetone to rid it if any residues works really well.

[DVT873]

(01-12-2021 )Craig Wrote:  Thanks so much for you input, I will have to take your response back and try and get the answers. Sounds like it's going to be expensive, however, they just bought a new truck and I think you may have saved it from the same fate as this one. I'm going up there this weekend so I'll get some answers and try to create a game plan to go through all the systems you mentioned. Or, after reading your response, he may just want to demandate it because of cost. I'm trying to get him to fix it for obvious reasons, yearly inspections and such but didn't really know where to start but now I think we have a jumping off point for sure, can't thank you guys enough :).

Have you run it down the road with the cans off to see if it is making smoke? Twice I have had units make noticeable smoke, especially on acceleration. Clean out the EGRDP ports, one needed drilled and the smoke stops. The EGR DP sensor ports are tough to get clean. They can fool you because of the way the passages are drilled.
Cummins bulletin 5579934 covers that although the pics aren't the best. I don't trust EGR valves to report their position correctly. Replace it. There is a DPF Regeneration Stay Warm feature that can be turned on. See TSB 170058, note that is not available before 2010.
Minimum regen set speed is often at 25mph or higher. This can be set to 5 or 0 if the program allows it. Avoid idle whenever possible or set the RPM up to 900-1000.
All of the above is mainly directed at school buses but helps any stop and go application. Extended idle on these will carbon pack the rings. Most if not all ISB's do not have a 7th injector. They dose fuel into the cylinder on the exhaust stroke. If the regen system is out of wack this can lead to cylinder wash down. An oil sample will show % of fuel dilution. I like how NAPA reports the dilution. Anything above 5% indicates a problem. Ideally 1 or 2%.
Follow up all of the above with EGR tuneup and replacement of sensors and EGR valve.