Cummins ISX CM871 Technical discussion

We're going to run down to Delmarva tomorrow and see if after a few longer runs we can manually regen.
We'll see if the codes go inactive.
Exhaust is tight but I'll look at every joint and gasket.
I'm looking at Jet coating all the piping and elbows, inside and out.

After everything I've read here, EGR tune up is as important as changing oil and filters.
Really thinking a Spinner would be a good investment with this engine.
The other addition would be dual lube filters, like the old Luberfiners for cooler oil temps, more passes in radiator, adding high end CAC.
Keeping soot build up in the oil and temperatures under control is key.

 

I am not promoting him or anything, but for those still looking for him, he can be found on his own forum now. Its Rawze (dot) com

 

i have a 2006 cummins isx thats getting verry poor MPG and power , im getting about 4.5 , cummins has had it 3 times and they are really just shooting in the dark because 6000.00 later no change. another driver and i was talking and he said it could be sucking air , so today while idling i looked at the fuel seperator and there is small bubbles cumming up and when i step on throttle they get bigger , im thinking under a pull its really sucking bubbles, i get the truck serviced every 13 to 15,000 so im sure every tech is not installing gaskets wrong. ANY SUGGESTIONS ?? Thanks

 

I have 6.7 cummins. Blowing black smoke. Replaced dpf, egr cooler, and turbo. Reflashed computer and ran well for about 20 miles. Then started smoking and irratic running. Found small leak on crossover tube at egr cooler. Could this be causing my problem? Don't want to take back to shop after $8000 im broke!

 

Hello Mark, I'm no expert, but am willing to help. Any exhaust leak isn't good.fix it and
one maybe problem solved. Have you replaced air filter? Engine needs air to burn fuel
Could be cause of black smoke? Are rubber connectors sucking shut on air crossover pipe?,
any restrictions in pipe?,Has IMAP sensor been changed?, How is your EGR valve,is it sticking?
What year is truck,and engine serial number? How many miles or engine hours? Sounds like
you spent a ton of money and no success. What was initial problem .

 

Air, oil and crankcase filter changed. Picking up gaskets for leaking crossover tube tomorrow. IMAP sensor I have not checked. Truck is 07 ,6.7. 160,000 miles. Many hours idling. Initial problem was smoking and engine lost all power then died. All trouble codes were related to emissions. Started with DPF. It had holes burned through inside. Had to replace. Started truck and turbo seals were shot. Replaced turbo. Went ahead replaced EGR cooler also. I am hoping leak is causing sensors to react. I will check EGR valve also. Can valve be checked on truck? Thanks.

 

Can you please read what my driver is explaining and any insight would be greatly appreciated. 09 International Prostar ISX

"for a little while there has been a strong smell of diesel. most times when I smell it, the warning light for emission control system is on. It is the warning light indicating the exhaust is getting hot and carbon accumulating. I think that it is when the diesel is being sprayed into the exhaust pipe. I don't think all the diesel is going into the exhaust pipe. Twice today, I smelled the deisel. The first time the warning light was on and when I slowed down a cloud of vapor or mist (it almost looked like steam) that lasted a few seconds came from under the hood on the passenger side closest to the windshield. When this happened there a very strong odor of diesel. It looked like a cloud almost. It was a very big puff. It came from around where the windshield wipers are. I pulled over, lifted the hood and looked everywhere and couldn't see where it came from because everything was dry and wasn't coming out anymore. I continued to drive and about 100 miles later I had stopped at a light then continued in a low gear range about 20 miles an hour and as I came up to my destination, I turned into the driveway and another big mist came out but this time it was really big and you could actually see the droplets of liquid in the air, but it was on the other side of the hood this time. The engine is not over heating. After finishing at my destination I drove 2 miles to park the truck for the day and nothing else occurred."

 

Check the fuel lines that are going to the doser valve. There is an upgrade kit from Cummins available. The doser valve is mounted after the turbo in the exhaust system and has fuel and coolant lines going to it.

 

I would recommend checking the exhaust pipe mounted directly behind the doser. (turbo, doser, exhaust pipe) On the spec drawing there is no gasket, however, International sells a gasket that fits in this spot. In my case there was no gasket, I removed the clamp, installed the gasket with a new clamp and the problem was gone. Considering you are getting a "mist", and it sounds as though it only happens when the doser is on, I would check the pipe first. JMO

 

On a ISX cm871 engine I think you have to remove EGR valve to check valve actuator
for cracks or other damage, and inspect EGR valve poppets for a stuck open condition.