CM 871 won’t regen

[theironoracle]

   

Thanks for the add. New member, first post.

How do I add a photo? I have a picture of an after treatment history I need some explanation on so I can fix this truck not just force a regen and send it out the door.

I had an active code for DPF spot load above normal moderately severe, I don’t recall the number.

Attempted forced regen. It would not regen

The target after treatment DPF regen not met
DPF intake temp low. Max was 767.5. Hot idle 212
EXhaust has pressure above max pressure. 169 max 35 hot idle
IMAP above max. 25.9 max. 1.2 hot idle
Turbo speed above max. 58984 max. 20281 hot idle

After letting it sit overnight and reading the forum I performed a filter maintenance reset. Forced regen worked as it should.

This is where I need to post the picture of the after treatment history. I will try to explain the results.

Ending soot load “above normal least severe” 2042 hrs. But my DPFDP is .9? This doesn’t seem right?

Also my max spot load history is 11 hours prior 2031 hrs “above normal moderately severe” at dpfdp of .7?

And the regen prior to the one I did was at 1960 hrs! How did this happen?

Ecm was changed a few years ago that’s what the hours is about. I rebuilt the motor a year or so ago let’s say 1000 hrs, piston packs, valve guides and seals, turbo and actuator, injectors probably. At that time it got a complete egr tune up and visually inspected DPF no visual problems and washed out with hot pressure washer.

Any help would be appreciated TIO [/php]

[theironoracle]

Well I figured out the pictures at the end but kind of messy I’m learning!

[RTRUCKING48]

Did you performed the Egr tune up whe was the last time you changed the dozer injector, did you check if dozer injector not leaking or clogged with soot?

[theironoracle]

It has not had a doser injector in the last 5 years. From the work orders I have looked at from the dealer where it went its first five years I haven't seen anything about a doser injector being replaced. I have visually inspected annually for about 5 years and it always looks perfect. No carbon build up at all. The entire truck only has about 10,000 hours on it. The truck is a seasonal construction dump truck.

[Rawze]

The numbers on the far right column should not be averaging 3.0+... There has been a problem the whole time. Can be a lot of things including sticky egr valve, CAC leaks, clogged cross tubes for the DPF, Bad DPF Delta-P sensor, bad DPF Temp sensor, incorrectly reading IMAP or other sensor,.. etc. etc.

Pull the cans, both the DOC and the DPF,.. take pictures of their faces and post them here. That will tell you a LOT. While they are off, have them baked and flow tested.

-- You should NEVER EVER do a maint reset on the system without having the DPF and DOC flow tested/baked as it will reset it in a partially blocked state and throw off all the readings!. Now, the only way to fix this mistake is to to pull your DPF and DOC and go have them flow tested and baked out,.. THEN DO A PROPER RESET ON THE SYSTEM WITH INSITE!
ref: http://rawze.com/forums/showthread.php?t...0#pid25590

[Nilao]

I don't know if anyone else saw it but he pressure washed the dpf. So most likely it is still partially blocked with concrete now...never use water to clean the dpf system.

[theironoracle]

Thanks for the help. I will remove the DPF and Doc and post pictures Monday or Tuesday and send them to town for a proper cleaning. I guess I misunderstood what I was reading on the forum in regards to needing to do the maintenance reset sometimes after engine derates due to DPF plugging, lesson learned.

I absolutely watched the readings from the sensors you listed during both the unsuccessfully and the successful regens and everything seams to read what I think they should during these processes. Curious how a person tests these properly or should I plan to blindly replace everything and clean tubes.

I did a charge sir cooler leak test as part of the overhaul. But I will do it again.

Why do IMAPs read zero with key on engine not running?

Is there a way to actuate the EGR valve in Insite? ET has that function but I didn’t see it in insite.

I do wash DPFs with a steam cleaner. It seems to have worked fine a half dozen times? Just need more thoughts on this. Just for giggles I think I will remove and take pictures as suggested, steam clean them, then take them and have them cooked. The first flow test will show how clean I can get them. What do you think?

I am grateful for all the knowledge you guys are willing to share. TIO

[Nilao]

I may be wrong on the imap but i believe the ECM offsets the reading with the barometric pressure sensor that way the only pressure it reads is boost.

The egr should have a test under ECM tests i think. It's in there somewhere.

[Rawze]

(05-04-2019 )theironoracle Wrote:  ...
I do wash DPFs with a steam cleaner. It seems to have worked fine a half dozen times? Just need more thoughts on this.
...

I guess the concept of "rare and precious metals" never crossed your mind? -- YOUR DESTROYING YOUR DOC AND DPF!!!!!!!!!!!!!!!!!!! -- Seen plenty of guys say thay got away with it a few times, only to regret it big-time later. Each time you do that, it makes it more and more difficult for them to operate correctly.

NEXT is the fact that 50% OF ALL THE HOLES IN A DPF ARE SUPPOSED TO BE BLOCKED OFF AT ONE END!. This is so that it can properly trap soot and fuel as it regens. -- ANY KIND OF LIQUID will very quickly start to cause damage.

I know of a fleet that had 500 trucks, that had to replace more then 200 DPF's because the shop manager decided to start steam clean them too. -- They regretted it after about 3 times of this too, as trucks were failing and shutting down on them left and right at a highly accelerated rate.

Lot of garbage on the internet,.. one of them is running around claiming they wash or steam clean out their DOC, DPF, and/or SCR cans. -- I DO NOT ALLOW SUCH BAD/MISLEADING INFO ON HERE!!!! Truck owners have a hard enough time as it is to be doing garbage like that and making their problems worse!.


AND IF YOUR A MOBILE MECHANIC LIKE YOUR BIO CLAIMS -- AND YOUR DOING THIS TO YOUR CUSTOMERS TRUCKS --- I SUGGEST YOU STOP THAT PRACTICE IMMEDIATELY!!!