Holey DPF!

[Chamberpains]

Check the boots by pressurizing the whole engine. Intake and exhaust. You may discover you have other things leaking.

[DVT873]

"Exhaust leaks sometimes a tell tale sign of an exhaust leak is an excessive amount of white smoke when it regens during driving its letting enough O2 get into the system and the doser fuel ignites before it gets to its intended destination."
In the last 12 months I have seen this smoking problem several times. All on EPA 07 engines that do not have the 7th injector but inject fuel on the exhaust stroke*. Not Cummins. Medium duty MaxxFart 6 cyl. I could use some help with the exhaust leak idea. Replacing DOC's seemed to fix them. I was not satisfied with the diag. process that got to that decision. Service information is not conclusive. Even with OEM dealer level software a regen cannot be forced if the computer says a regen is not needed on the 07's. I was able to fake out the DPFDP signal and get it to regen. Smoke poured out and smelled of raw fuel. Repeated with new DOC's and they went into regen. Reading Lonestars post makes me wonder if I missed something. I did check for intake and exhaust leaks early on. If there were leaks in the exhaust wouldn't you see smoke at the leaks? All mine was coming out the tailpipe. Open to thoughts.....
*I am sure this incredibly stupid idea has been covered at length on here. All of these regen systems seem to have been designed around continuous on highway full load high speed operation. You guys have seen how well that has worked for you. Imagine in town stop and go low speed cycles. Schoolbuses, dump trucks, beer trucks, mixers, ambulances etc.

[Lonestar10]

before i removed my junk i had white smoke during regens pouring out of my cm871s stacks. come to find out i had 2 cylinders leaking on the manifold. would only puff white when taking off from stop lights/signs during a regen. any time my "exhaust temp" light would be on at a light i knew it would throw smoke, also regened every 2-4 hours according to insite. had baked/tested dpf/doc and new doser with only 150k or so on them. and pretty sure theres a crack or something in the flex pipe to the can as it didnt smoke then but this winter with garbage gone and some leaking exhaust valve seals after 11-12hrs of idling smoke would come up from under cab when i take off.

[Evotrucker]

(05-19-2019 )Chamberpains Wrote:  Check the boots by pressurizing the whole engine. Intake and exhaust. You may discover you have other things leaking.

can you tell me how you would pressurize a entire engine and where to start? :D

I'd love to know so i can try it on my cm870.

Dont mean to hijack the post!

have a good day, gentlemen!

[Chamberpains]

Just like the ISX, pull your turbo exhaust pipe off measure the outlet and shove a plug in there to seal it off pull the intake side off shove a plug in there. Then find an opening to pump air into up to. Usually the turbo outlet temp sensor or maybe you can pull the boost sensor out it's different on all engines and manufacturers. But there's usually a plug somewhere that you can access. then start filling a system with hair off a pressure regulator up to your desired PSI. Usually 20 to 30 works to expose all leaks on the intake piping and exhaust.

Its posted on here how to pressurize the whole engine. With links to what plugs or at least what type of plugs to use.

[Rawze]

(05-20-2019 )Chamberpains Wrote:  Its posted on here how to pressurize the whole engine. With links to what plugs or at least what type of plugs to use.

these came up on search..
ref: http://rawze.com/forums/showthread.php?t...07#pid8307

and: http://rawze.com/forums/showthread.php?t...19#pid1619

[smorgan87]

If u went so far as to drill holes in the dpf why didnt u just gut it or weld a pipe in the thing and tune the truck?

[hookliftpete]

It’s a much shorter process to drill some homes...unfortunately I’m an expert at disassembling my after treatment...I’m already used to having to watch this mess in a daily basis, so this was the easiest solution for the time being...as others have mentioned, not a permanent fix, but it keeps me moving.

This truck carries dumpsters, so highway time is infrequent, which I’m sure contributed to the problem significantly.

Doing a forced regen on it at this moment, second one since the holes, all is well at this point 6 weeks in.


I’ll probably pull the system off and do a visual inspection at next oil change, which should be mid to late July.