CM871 Slow Climbing Regen Temps

[Taco05]

I have a 2009 ISX and the Filter IN and Filter OUT temp take more than 15 min to reach 900F. Egr valve has been replaced before, both Delta P sensors are new, Imap and Exhaust pressure sensor are also new. Also new Doser installed a week ago. I have checked all the tubes to the Delta sensors and cleaned them as well. DPF filter and DOC have been at Cummins for cleaning 2 weeks ago and both passed. The truck is asking for a regen almost non stop and when I do a forced regen it smokes quite a bit but there is no oil or coolant consumption. Aftertreatment diff pressure stayed between 2.5-3.5 inHg during the last Regen but history showed 8-9 inHg pressure for previous regens.
Truck is doing a run right now should be back at the shop in 2 days and I will check the aftertreatment history for frequency of regens and diff pressures.
Any Idea what else could cause this non-stop regen request, slow temp climb and high diff pressure? I was leaning towards a new DPF filter even though cummins said it passed inspection and cleaned out good.

[Rawze]

How old is the DOC? DPF?

what does the history look like?

how may miles on the engine? truck?

[Taco05]

Truck has 950,000 miles but I only had it since about 700,000 and I haven't changed them since but they look like them have been replaced before. Pressures under regen history were all around 8-9 inHg but I have done some more work since so I will have a better idea when he comes back in couple of days.

[Rawze]

(03-28-2016 )Taco05 Wrote:  Truck has 950,000 miles but I only had it since about 700,000 and I haven't changed them since but they look like them have been replaced before. Pressures under regen history were all around 8-9 inHg but I have done some more work since so I will have a better idea when he comes back in couple of days.

The engine is likely so old and worn now, that no matter what you do,.. it will not likely regen properly due to all the engine wear. Seems to me that your possibly fighting an uphill battle at this point.

The DOC will only last about 600k miles on a truck with zero oil consumption, IF YOUR LUCKY,.. and on an engine that old, it is likely washed out again after only about 250-300k miles.

8? -- 9? --- HOLY SMOLY! -- -THOSE NUMBERS ARE ABSOLUTELY HORRIBLE!!! --- CAN BE ENGINE DAMAGING IN FACT! -Anything above a 3.0 will start to cost you fuel mileage and above about 4 - will make for power loss, excess heat at the turbo, and 8+ can cook injectors and cylinders!.... Your severely punishing an already almost dead horse there!.

You have a couple choices,..

* Remove the "Mandate" and get ready to inframe it very soon, or just go ahead and inframe it now, then remove the mandate after, instead of wasting another $7,000 on new "cans" all over again.

* Get Insite and keep force-regen it every week until it eventually cracks and destroys the DPF can from having to force regen it so much.

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Either way, you should have preparations in place for an inframe very soon, especially if it has lived a life of EGr without any kind of secondary bypass filter on it to help keep out the 6 lbs of soot that goes through the engine oil every 45,000 miles.

[Taco05]

When you say engine damage what do you mean specifically? Not enough exhaust pressure, too much blow-by? The pressure we are talking about is the actual pressure drop across the DPF Filter (change in pressure before and after DPF) which should not go about 3 inHg. So if the filter is really clogged and past the point were a forced regen can clean it out would't it show really high numbers like 8-9 or am I missing something? Last regen finished good in about 45min and differential pressure code went inactive, soot load went from least severe to normal but 30 min later it was asking for another regen. I will see the truck today and get all the numbers again including the turbo specs which I am suspecting the most since I have not changed it and it is red which might be the original equipment but the actuator has been replaced.

[hhow55]

Well Mr Taco, you can check all the things you want, but like RAWZE says, your motor is worn out, and very near the end of its life!!!!!

[Taco05]

Sure I can believe that but I am trying to understand what exactly is going on with it. How can we tell apart bad DPF and DOC from a failing or weak turbo or a worn engine?

[Waterloo]

(03-30-2016 )Taco05 Wrote:  Sure I can believe that but I am trying to understand what exactly is going on with it. How can we tell apart bad DPF and DOC from a failing or weak turbo or a worn engine?

I am not the wizard of smart on any of this, but when my DPF failed, I had soot in the exhaust, in my case my tail pipe as I have a weed burner. Check the stacks for soot.... I took the mandate off at that point and got another 70,000 miles out of her, she is in the shop having an in frame at 900,000 miles... Sounds like she is toast...

[Rawze]

(03-30-2016 )Taco05 Wrote:  When you say engine damage what do you mean specifically? Not enough exhaust pressure, too much blow-by? The pressure we are talking about is the actual pressure drop across the DPF Filter (change in pressure before and after DPF) which should not go about 3 inHg. So if the filter is really clogged and past the point were a forced regen can clean it out would't it show really high numbers like 8-9 or am I missing something? Last regen finished good in about 45min and differential pressure code went inactive, soot load went from least severe to normal but 30 min later it was asking for another regen. I will see the truck today and get all the numbers again including the turbo specs which I am suspecting the most since I have not changed it and it is red which might be the original equipment but the actuator has been replaced.

Ever see a car with a blocked up catalytic converter? -- Car runs fine mostly (for a while anyways), but the exhaust manifold will glow red.


After a forced regen it should be BELOW about 1.8 or so max. Otherwise it did not perform very well, and it will ask for it again in short order.

What you should be seeing is a forced regen about 1.2 - maybe 1.5 or so, but realistically, it will typically be BELOW 1.0 aon a good DPF system in the history after the forced regen. -- And a history after several days should be an average of BELOW 3.0 -- if it is running higher,.. you have some problems there.

You said it is showing a history of 8+. THIS IS VERY BAD! It should not be more than about 3 or so max on average. If your getting 8's on the history,... it is costing fuel mileage and the higher it reads on the history, the more it is showing that it is creating excess heat buildup in the engine. High numbers like that can cause a lot of engine damage in short order. Here is what can and will eventually happen to it...


* at 8+ and 9+ all the time ----

* Cook the injectors and cause them to leak, become weak, and start to go bad. This will also make it run a bit rough at idle after someone does this.

* Eventually start to make cracks in the top of one or more of your pistons. Then they/it will fail several weeks to months later even after the problem is fixed, when the exhaust gases finally drill holes through them to the bottom. You cannot know this is happening without boroscoping the engine a couple weeks AFTER the problems have all been fixed.

* Cause a cracked Intake or exhaust Valve.

* It can contribute to and/or cause the engine to drop a valve, damaging the head severely.

* Crack the head.

I.E. -- Damage

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Stuff up the exhaust in ANY engine and see how long it lasts. It is very real.