Cummins ISX CM871 Technical discussion

bizzzzzz1 · Dec 8, 2013

Vaneser said: ↑

Is in USA ,esta en Estados Unidos.
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Between $8k to 10k. It cost me 9500

bubbanbrenda · Dec 8, 2013

http://www.thetruckersreport.com/truckingindustryforum/trucks-eighteen-wheelers/224236-cummins-isx-cm871-engine-sensors-location.html
CM871 sensor map, thanks again Heavyd

shawn_ca said: ↑

Where is this on my Cummins ISX CM871 ? can someone please post a picture ?

Exh. backpressure sensor and feeder tube, and EGR temp. sensor. ?

is it EGR Temp Sensor > Delta P sensor same ?

Exhaust Backpressure sensor is Doser ?
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Classone · Dec 9, 2013

Thanks Brenda...

o/otony · Dec 9, 2013

Vaneser said: ↑

Is in USA ,esta en Estados Unidos.
Click to expand...

en que estado?

kw08t660 · Dec 17, 2013

Rawze said: ↑

I am creating this thread so that those who know, own, and/or repair this particular engine can learn from each other. I have one of these engines in my truck and know much of its secrets. I have helped many, many people solve the elusive EGR, DPF, fuel mileage, and other problems that regularly plague this engine, and have learned much in return. So far, most of the problems I have seen O/o's have with this engine, stem from neglect of key components that need regular attention, so I will open this thread with a list of what I have found that should, by now, be considered common knowledge. First tho, I would like to share my personal opinion of this engine. When comparing it to other brands of similar age/style, I think that for the one-truck O/o, among these newer Post EGR/DPF egines, the CM871 is the easiest, least expensive engine to keep healthy with its EGR/DPF intact, while maintaining decent fuel mileage long term. There are many who will disagree, because there have been way too many unnecessary bad experiences by drivers and truck owners that speak otherwise. Hopefully, this thread will put a stop to some of this through shared experience and education, allowing us O/o's out here to keep more of our hard earned cash, rather than giving it to the now, way-overpriced dealers and engine shops that are all too eager to blame a turbo or other major component, when most often, its likely to be a dirty sensor or a pipe that has gotten clogged with soot. This bothers me greatly, because I think things like this have happened so often, that it has now become common knowledge to just assume the turbo's/dpf's/egr valves on this engine are just bad/junk, and are the likely cause, when in fact, very often they are not. I am not here to post about how great this engine is by any means, sure it has its flaws, like any other engine, but it definitely is not as bad as most would have you think. One of the biggest downsides I think, as a truck owner with one of these engines, is the fact that this engine likes to be worked on at least every 200-250k miles or so, to keep it healthy, especially if the EGR/DPF is in tact and operating. Why is this a downside?,...Many truck owners these days are NOT mechanically inclined at all, nor do they have the wish to become so. For these type of truck owners, this is definitely an expensive engine, because they will typically run to the nearest dealer/shop whenever something is not quite right. This, very often, lands them in an endless loop of problems that seem to have no end, where the shop will milk their wallets dry, throwing major components at the truck repeatedly.
Truck owners who do this, after spending many thousands on what are typically 'ghost problems', will usually hate the engine and its egr/dpf systems, blaming their lemon truck, rather than taking the extra step to educate themselves on how to keep that truck out of the shop. Other O/o's, after having problems, will try to learn about these systems and their trucks to reduce shop-time, often are guided by those same shops that are milking them dry, where it ends up doing little to help them as a result. What you end up with, is a bunch of bad information, half truths, and a general flood of mis-information based on people's opinion. This is why I chose to specifically talk about a single model engine here instead of trying to cover all of one brand, because the wider the paintbrush used, the more blurred the image becomes.

What should be Common knowledge of the EGR/DPF system on this engine (this, i have posted before, just putting it here to start the thread)...

These are the steps (An EGR Tune-up) to perform every 200-250k miles on the CM871 ISX engine to prevent or stop some well known symptoms that will usually include one or more, but not all of the following symptoms...

Reduced fuel mileage
Lack of power
Sluggish throttle response
Little or no acceleration for several seconds
Surging or power increases above 1400-1500 RPM.
Rough idle / fluctuating idle

Frequent Regen lights / alarms
Frequent Regens / parked Regens
DPF faceplug alarms
DPF Inlet temperature alarms

Slight oil pressure drop after only 15-20k miles after oil has been changed (clogging filters).
High amounts of soot in the oil
Crank case filters clogging too often

Turbo hesitaion/lag
Turbo coughing
Turbo Actuator Alarms
Turbo overspin
Charge Pressure faults
Turbo inlet temperature alarms

EGR actuator alarms
Delta-P alarms

Here is some info along with what I usually recomend someone do to their truck concerning only an egr tune-up, asuming this has never bee done on thier truck, and there aren't more obvious problems like a bad CAC,etc. Its a re-post on what to do to a used truck after purchasing it...

<> EGR cooler, Visual: Looking to see if it has ever been replaced. Replacements are typically silver in color, or show signs of being re-painted. If it HAS been replaced, this is a good sign. Failure rates on these are high during the truck's first 180-200k milage range, where the warranty will still cover it. They fail due to settling of the block during the engine break-in period, causing mechanical stress to the unit. Cummins Engineering, when I asked about this in 2010, informed me that it was an 80% failure rate, and that they did studies on loosening/re-tigtening the bolts to relieve stress with little results. Replacement is more effective. After that first failure, re-occurrences are not common unless the engine suffers conditions that cause the block to 'settle' again, like say changing its governed speed by a large amount and driving it hard at the new speed. Regardless, keep a close eye on coolant levels, marking the tank at a given known coolant temperature. A leaky EGR cooler will shorten the life of just about everything on the engine very quickly. White smoke from the exhaust and coolant loss are typical of a bad EGR cooler. It will also cause carbon and soot to cache up in the intake manafold, lowly choking the engine.

<> DPF, Visual: Look for signs to see if it has been removed/replaced. If it HAS, this is a red flag. The DPF on a cummins is big enough to sustain a healthy exhaust flow for about 700k+ miles, where ASH, not soot or coolant, will finally cause it to read above 3.0hpa on a constant basis (above 3.0 costs fuel mileage). The only exception to this is if it gets cracked/damaged due to excess road stress or being impacted by road debris (not very common but can happen). Why then is it so common for it to fail or be replaced/cleaned before this mileage range?,...Outside problems, #1 being the after-treatment injector going bad, then second, a poorly running engine that produces a lot of excess soot, or a bad EGR cooler plugging it up with coolant. ALL of witch can be avoided, with good maintenence practices, long before it kills the DOC/DPF. If it has been replaced or cleaned at 380K miles or less, then it is highly likely there were, and are still problems with the engine/EGR system. Removing the DOC/DPF should only be a LAST-RESORT type item when everything else has been done to avoid it, and it is the only thing left, after replacing the injector/sensors with a new ones and force-regening it to determine its actual hpa.

<>Determine/Remove the soot buildup in the EGR system: Remove the IMAP sensor from the intake manifold. Very easy to do, takes less than a minute. If it is buried in soot, and it will be, at 250k+ miles, it is, at the very least, costing you fuel mileage by now, or at its worst, causing turbo problems, power loss, hesitation in the acelerator, and/or excess soot problems. You will get turbo actuator alarms long before you get alarms for this sensor being cloged. Many mechanics are fooled by this, chasing ghost problems in the much more expensive components like the turbo, egr valve, etc. I have the Insite/ Fault tree software. On its best dsays, it is only about 30% acurate in dealing with these type of ptroblems. The IMAP sensor, most of the time, can siply be cleaned using a dry toothbrush and NO chemicals. This one sensor has actually put many O/o's out of buisness. I have witnessed trucks go from 4-mpg to 8-mpg, just from cleaning it.
Assuming it was in fact covered in soot, you will need several cans of 'Carb and Choke' cleaner. NOT 'Brake cleaner'!!!. Brake cleaner turns everything into a soot magnet. You will have to remove the intake manifold, Venturi (egr mixer) pipe, and Delta-P crossover tubes, washing them out, to bring back the engine's full fuel mileage potential and New-running glory. The Delta-P (EGR Differential Pressure Sensor), if it is the origional from the factory (painted red), it will have to be replaced. It cannot be cleaned properly without it giving false readings afterards. As this sensor clogs up, it causes EGR valve and EGR actuator alarms and problems, power loss, fuel mileage loss, and 'turbo-coughig' problems, quite often without ever throwing a code for the sensor.

<>Clean/Replace Exhaust Manifold Backpressure sensor: This sensor usually lasts 400-600+k miles before giving problems. It can usually be just simply cleaned, along with its feeder tube, comming off the exhaust manifold. If it is going bad, the turbo will act up. Symptoms can be of,...Turbo-coughing, turbo-lag, actuator alarms, turbo overspin alarms, and/or even turbo inlet temperature alarms. This sensor can actually kill a turbocharger over time, and/or can cause a cracked head or gaskets from excess head pressures generted by the turbo acting up. This sensor can be cheked with Insite to see if is reading correctly if it is in question, but its a cheap sensor, so just replace it if its suspect.

<> The After-treatment injector (doser injector): It operates similar to a spray-can nozzle and is located at the turbo exhaust outlet. It is easy to inspect by simply removng the 2 exhaust clamps on either side of it and looking down into the pipe. They start clogging up at 250k+ miles like clockwork, even on engines that run well and have never been idled, causing many DPF and Regen problems when they do. They are easy to change, but only if your willing to drain your coolant into some buckets first (that kinda sucks). Yes it can be cleaned, and that helps the DPF a lot, but NO, most of the time, after cleaning it, will it last very long afterwards. It also costs you fuel and can leak coolant directly into your DPF as they go bad or fail. Not worth the risk of cleaning it if u ask me. The doser injector is also a money-maker for most of the dealers. They will almost always go straight for the DOC/DPF when you visit them, ignoring the injector because of the all-to-typical 'DOC/DPF Face-Pluged alarm' that is thrown by the engine, when there is little or nothing much wrong. The engine likes to throw this code waay too aesily, and many O/o's fall victim to it when they visit the repair shop, many times, repeatedly, before the actual, more minor problem is found.

To sum all this up,...

every 250-300k miles,...
Remove and clean the IMAP sensor, Intake manifold, Venturi pipe, Delta-P crossover tubes, Exh. backpressure sensor and feeder tube, and EGR temp. sensor.

Just replace the Delta-P sensor and After-Treatment injector. Then perform a DPF 'Forced Regen', ensuring the DPF is still below 3.0 hpa (it will almost always be below 2.0 hpa after a good cleaning by the regen with new after-treatment injector).

cost?,...$300-400 for after-treatment inj., $150-200 for Delta-P, 3 five-gallon buckets for holding your coolant, and a day of downtime, while drinking beer and getting very dirty. If you can change a spark plug for your car or lawn mower, then you are very likely capable of these things as well.

Can a shop do this for you?,...well,...possibly for a few thousand bucks. Not worth taking it to them if u ask me.

Ignoring it,...Countless truck problems, downtime, and thousands uppon thousands in repair bills by the truck steeler(dealer) because they will blame the bigger ticket items either out of ignorance, or for extra profit. Most will laugh at you for mentioning simply cleaning these things instead of replacing them.

Maybe this helps someone out there who is already having issues,...Rawze.
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Its been 40k miles i just got a new egr cooler and this last trip averaged 5.25 69 max speed 76k weight 2008 t660 455 isx 10spd. And when my driver overheated my engine the coolent was leaking from the dpf and haven't cleaned the dpf since only regen will this be a problem and how could i know if my dpf is bad.

allan82782 · Dec 17, 2013

Thanks for the info. I just bought the insite program I have a fault code 4214 on a 2008 international prostar isx. Cummins but cant find out how repair the issue its not in the fault tree information. Can u help me im a o/o thats learning how to understand theses newer engines cause I had my share of dealership experiences

Blind Driver · Dec 21, 2013

My CM870 just blew the turbo. Boss told me this is the third turbo this month.

MRTKW · Dec 22, 2013

Can you help on cm2250?

shawn_ca · Dec 22, 2013

Can anyone give me any idea why My ISX goes low on oil about 1 gallon at 11,000 miles.. I usually do oil change at 12k-13k with new filters and Rotella oil I buy from Sam's Club. Truck have no issues it runs great no problems at all but why it needs gallon of oil, my other truck detroit doesn't suck any oil at all.

Blind Driver · Dec 22, 2013

shawn_ca said: ↑

Can anyone give me any idea why My ISX goes low on oil about 1 gallon at 11,000 miles.. I usually do oil change at 12k-13k with new filters and Rotella oil I buy from Sam's Club. Truck have no issues it runs great no problems at all but why it needs gallon of oil, my other truck detroit doesn't suck any oil at all.
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Every truck I've driven does that.

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