cm 871 regen fail
02-25-2020, (Subject: cm 871 regen fail ) 
Post: #1
cm 871 regen fail
got a cm 871 that fails to regen. remove and cleaned dpf and doc. both were in good shape and were cleaned properly. (reset in insite) cleaned the dpf deltap sensor tubes. cleaned the egr deltap tubes and ports. cleaned imap sensor. also cleaned the doser. had a major exhaust leak after turbo that was repaired and had a major exhaust manifold leak that was repaired as well.when i do a forced regen on a cold engine the readings are as follows:

egr diff pressure = .05 to .07 (fluctuates)
egr valve pos = 0%
egp = 120-130 (fluctuates)
imap =12inhg
percent load = 0
turbo act position = 89%
turbo speed = 42000-43000 rpm.

the engine will ramp to 1100rpm and doc heat will build to around 525 and it will start to dose. dpf temps will raise to around 650-700 and the doser will close and temps will drop back down to 470 deg on doc. the temp will then fluctuate to 500 untill the engine fan kicks on and lowers it back to around 470. it will be stuck in this cycle until i stop it. after the engine is warmed, when a regen is attempted the temps will never get past 480-500 deg while cycling the engine fan. these are the readings at that point.
egr diff pressure = .5 steady
egr valve pos = 0
egp = 150-160 fluctuates
imap = 18-22 fluctuates
percent load = 0-4 percent depending on fan
turbo act position = 88-92 fluctuates but stays mostly 88-89
turbo speed = 53000-58000 rpm fluctuates
replyreply
02-25-2020, (Subject: cm 871 regen fail ) 
Post: #2
RE: cm 871 regen fail
for starters you need to do an egr tune up https://www.youtube.com/watch?v=FhJxpyS5MpY Those sensors must be replaced not cleaned. The IMAP in particular has the pressure sensor up inside it and you can't get to it to clean it.The readings your looking at could be incorrect if the sensors arent reading right. Replace the doser also, it may not be spraying properly, that could cause it to not get up to temp during a regen. When you say the dpf and doc were cleaned "properly" what exactly does that mean? How did you clean them?


User's Signature: Warranty??? Yeah right, I am the warranty!!!
replyreply
 Thanks given by: Waterloo , hhow55 , Brock , Rawze
02-25-2020, (Subject: cm 871 regen fail ) 
Post: #3
RE: cm 871 regen fail
(02-25-2020 )tree98 Wrote:  for starters you need to do an egr tune up https://www.youtube.com/watch?v=FhJxpyS5MpY Those sensors must be replaced not cleaned. The IMAP in particular has the pressure sensor up inside it and you can't get to it to clean it.The readings your looking at could be incorrect if the sensors arent reading right. Replace the doser also, it may not be spraying properly, that could cause it to not get up to temp during a regen. When you say the dpf and doc were cleaned "properly" what exactly does that mean? How did you clean them?

cleaned with this:

./uploads/202002/post_4856_1582687204_3f23c8fff3ccaea8fb314f448ba124d3.jpg
https://www.youtube.com/watch?v=0PVSz-F2x6A


i was leaning toward the turbo because it seemed to get worse as it warmed up but i didnt feel all warm and fuzzy about replacing it. its expensive and i didnt want to blow somebody elses money on it if it didnt need it. my plans were to replace those sensors and doser tomorrow and clean the egr valve and piping. then see what kind of regen it does after that. i think i will remove the turbo actuator and check the turbo linkage as well for binding. i just figured it would be worth a shot to post it on here a get a different opinion. thanks for the reply.
replyreply
02-26-2020, (Subject: cm 871 regen fail ) 
Post: #4
RE: cm 871 regen fail
If by chance the turbo actuator or turbo is in need of replacement, YTS Turbo in Griffin GA is the place to call. Do not waste your time and money on Cummins reman parts, their quality sucks. Many here can attest to that, including myself. YTS is the turbo and actuator go to shop. Just google YTS Turbo, Griffin GA. Mr Hagg recommended them to me and many others here, very happy, and less expensive than Cummins.
replyreply
 Thanks given by: hhow55
02-26-2020, (Subject: cm 871 regen fail ) 
Post: #5
RE: cm 871 regen fail
(02-25-2020 )NavistarIH Wrote:  got a cm 871 that fails to regen. remove and cleaned dpf and doc. both were in good shape and were cleaned properly. (reset in insite) cleaned the dpf deltap sensor tubes. cleaned the egr deltap tubes and ports. cleaned imap sensor. also cleaned the doser. had a major exhaust leak after turbo that was repaired and had a major exhaust manifold leak that was repaired as well.when i do a forced regen on a cold engine the readings are as follows:

egr diff pressure = .05 to .07 (fluctuates)
egr valve pos = 0%
egp = 120-130 (fluctuates)
imap =12inhg
percent load = 0
turbo act position = 89%
turbo speed = 42000-43000 rpm.

the engine will ramp to 1100rpm and doc heat will build to around 525 and it will start to dose. dpf temps will raise to around 650-700 and the doser will close and temps will drop back down to 470 deg on doc. the temp will then fluctuate to 500 untill the engine fan kicks on and lowers it back to around 470. it will be stuck in this cycle until i stop it. after the engine is warmed, when a regen is attempted the temps will never get past 480-500 deg while cycling the engine fan. these are the readings at that point.
egr diff pressure = .5 steady
egr valve pos = 0
egp = 150-160 fluctuates
imap = 18-22 fluctuates
percent load = 0-4 percent depending on fan
turbo act position = 88-92 fluctuates but stays mostly 88-89
turbo speed = 53000-58000 rpm fluctuates

after the engine is warmed, when a regen is attempted the temps will never get past 480-500 deg


Bad doser, or doser valve not functioning, or possible ecm issue


User's Signature: It's hard to win an argument with a smart person, but it's damn near impossible to win an argument with a stupid person
replyreply
02-26-2020, (Subject: cm 871 regen fail ) 
Post: #6
RE: cm 871 regen fail
Watch my video on how a healthy CM871 regen process works. Take note of the time it takes for it to get up to temp... how high the temps go etc.

You mentioned that it only got to 700 gecrees or so.. this is too low and will cause the process to fail, or run endlessly. it should have quickly gotten to 900+.

Some thigs to also verify...

ENSURE the exact program in installed into the ECM for that model engine and truck. - Often, people will "uprate" the power by using a different program for the engine/truck and those emissions systems will act up and not function correctly.

The RPM readings for the turbo .... Depends on what model turbocharger and tier engine it has. you did not mention this. - a small tier engine will have higher positioning on the turbo during a regen cycle than what you mentioned and will have higher rpm readings. - A big-tier engine (500+HP, larger injectors, bigger impeller holset) will have the lower 85-89% range positioning and the much lower rpm on the turbo that you are seeing. -- Again, right back to ensuring the 100% correct program for the particular truck and engine is in the ecm.

Like others have said, REPLACE the imap and exhaust gas pressure senors if they are more thana year old. Do not rely on them, and they cannot be cleaned properly without them reading incorrectly after.

i talk about some of this stuff in this video. Here is how a healthy one should act...



take the time to watch through it as I talk about time it takes to get up to temp, etc. and a lot of other stuff.

And then there is the fact that no one has likely doen a thourough egr tune-up on it, cleaned out the egr valve, possibly the egr cooler removed and cleaned out or replaced if it is the origional (or at least 5+ years old) and it has been all these yaears later, etc. etc.
and it is no longer doing its job to keep exhaust empts down properly or is packed up and restrictive.

For the fuel to ignite properly and get that DPf quickly to 900+ degrees on its face, it needs to be spraying very well out of the doser injector. Cleaning that injector is a novel idea, but if it can;t regen properly and temps are the issue, the next step is to simply replace that doser, especially if it is old, has a lot of miles on it, like has been mentioned.

Exhaust/intake/egr piping leaks can caue it too. EGR piping boots across the back of the engine are notorious for developing a hole in them where you cannot see it. Plus the egr hard-pipe that leads away from the intake manifold, down to the top of the egr valve likes to rot out right at the top of the egr valve and leak like mad there, or pop loose form its welds. Give it a medium-hard yank and see if it has popped loose at the egr valve joint.

It is heavily recommended to make and insteall blocking plates at the intake of the turbo, and turbo outlet, and pressurize the entire engine up to 30 psi or so to find all the places that are causing boost, egr, and exhaust leaks. - It is amazing the places they can leak, like compressor pushing air into the crank case, egr piping elbow connections that have failed, and all sorts of places besides just the CAC.


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
replyreply
 Thanks given by: hhow55 , slowpoke , Brock , NavistarIH
02-26-2020, (Subject: cm 871 regen fail ) 
Post: #7
RE: cm 871 regen fail
(02-25-2020 )NavistarIH Wrote:  cleaned with this:


https://www.youtube.com/watch?v=0PVSz-F2x6A

Just for reference...this system is a decent system for cleaning the DOC/DPF out. I have seen them used a few times with some pretty good results.

Tags:
dpf machine, proper dpf machine, proper machine, cleaning machine, dpf cleaning


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
replyreply
02-26-2020, (Subject: cm 871 regen fail ) 
Post: #8
RE: cm 871 regen fail
(02-26-2020 )Rawze Wrote:  Watch my video on how a healthy CM871 regen process works. Take note of the time it takes for it to get up to temp... how high the temps go etc.

You mentioned that it only got to 700 gecrees or so.. this is too low and will cause the process to fail, or run endlessly. it should have quickly gotten to 900+.

Some thigs to also verify...

ENSURE the exact program in installed into the ECM for that model engine and truck. - Often, people will "uprate" the power by using a different program for the engine/truck and those emissions systems will act up and not function correctly.

The RPM readings for the turbo .... Depends on what model turbocharger and tier engine it has. you did not mention this. - a small tier engine will have higher positioning on the turbo during a regen cycle than what you mentioned and will have higher rpm readings. - A big-tier engine (500+HP, larger injectors, bigger impeller holset) will have the lower 85-89% range positioning and the much lower rpm on the turbo that you are seeing. -- Again, right back to ensuring the 100% correct program for the particular truck and engine is in the ecm.

Like others have said, REPLACE the imap and exhaust gas pressure senors if they are more thana year old. Do not rely on them, and they cannot be cleaned properly without them reading incorrectly after.

i talk about some of this stuff in this video. Here is how a healthy one should act...



take the time to watch through it as I talk about time it takes to get up to temp, etc. and a lot of other stuff.

And then there is the fact that no one has likely doen a thourough egr tune-up on it, cleaned out the egr valve, possibly the egr cooler removed and cleaned out or replaced if it is the origional (or at least 5+ years old) and it has been all these yaears later, etc. etc.
and it is no longer doing its job to keep exhaust empts down properly or is packed up and restrictive.

For the fuel to ignite properly and get that DPf quickly to 900+ degrees on its face, it needs to be spraying very well out of the doser injector. Cleaning that injector is a novel idea, but if it can;t regen properly and temps are the issue, the next step is to simply replace that doser, especially if it is old, has a lot of miles on it, like has been mentioned.

Exhaust/intake/egr piping leaks can caue it too. EGR piping boots across the back of the engine are notorious for developing a hole in them where you cannot see it. Plus the egr hard-pipe that leads away from the intake manifold, down to the top of the egr valve likes to rot out right at the top of the egr valve and leak like mad there, or pop loose form its welds. Give it a medium-hard yank and see if it has popped loose at the egr valve joint.

It is heavily recommended to make and insteall blocking plates at the intake of the turbo, and turbo outlet, and pressurize the entire engine up to 30 psi or so to find all the places that are causing boost, egr, and exhaust leaks. - It is amazing the places they can leak, like compressor pushing air into the crank case, egr piping elbow connections that have failed, and all sorts of places besides just the CAC.

Thanks for the info. Im going to watch the video.
replyreply




NOTE: Rawze.com is not affiliated, nor endorses any of the google ads that are displayed on this website.
  
  
Theme by MyBB Addict
Contact Us | Rawze.com | Return to Top | Return to Content | Lite (Archive) Mode | RSS Syndication