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inconsistent running - bendor - 10-04-2020

So here is my dilemma. i purchased a 2008 kenworth t 800 tractor with a isx 15 cm 871 485 horse with about 800.000 miles on it about this time last year from a out of the area kenworth dealer. I drove it back appr. 400 miles then it sat most of the winter because its a construction truck. When I purchased it they told me that they had just put a new turbo and actuator and dpf on it and i believe a new dosing valve. It looks like they did they had shop repair invoices. Upon trying to put this truck to work I have had nothing but issues. What it does is this. It could be day to day, hour to hour or even from shift to shift and seems to be getting worse as well it seems to me to be regening way way to often a couple of time a week it has less than 11000 miles on it since purchased. It will run up to 2000 - 2100 rpm and run good seems to have 485 horse but then it will sometimes only run up to 1700-1800 rpm and run or pull like it is derating to around 400 horse as well sometimes you will be accelerating and be about 1900-2000 just ready to shift when it suddenly acts like you shut the key off until it slows down to about 1600 then it will actually start to run like its derated again if you keep the pedal depressed. So far the local kenworth dealer has taken it in and each time said there you go its fixed. So far first time they claimed low coolant and replaced the coolant cap and cleaned the battery connections at that time they indicated that the turbo speed was a little low but should be good.2nd said it was charge air cooler so replaced that (nope). 3rd time finally quit so they replaced the ecm (nope). 4th time said throttle calibration it was fixed (NOPE). 5th time running down the road I believe the rebuilt turbo failed made a horrible noise like it was chewing itself apart then quit running. they agreed turbo failing. this has been going on for 2-3 months. At this time they will not warranty the turbo because it is out of warranty date by a couple of months. I am at my wits end this has to stop I guess its up to me now where do I start and look? I would appreciate any help you could give me! I am used to the old big cams and n 14 but know nothing about these isx's . Any and all help would be appreciated thanks again


RE: inconsistent running - Rawze - 10-05-2020

first of all, taking it to the stealers#it is your first and biggest mistake... they are as clueless as it gets and are only going to bandaide it and sell you parts. Your post above screams the typical scenario these days where someone does nothing but run off to the most expensive, most rip-you-off places (OEM network of complete idiots) they can and doing nothing but wasting nothing but time and money on it. Trucking does not work like that any more... unless you just want to be broke all the time.

If you don't learn to take a wrench to it, then it is going to bankrupt you.

* Order an inline-6 adapter off e-bay and stop taking it to the rip-you-off-r-us.stealersh%its.. it will pay for itself in short order.
ref: http://rawze.com/forums/showthread.php?tid=4841&pid=41621#pid41621

* While waiting a few days for the adapter to arrive, do a full EGR tune-up on it ... those morons at the stealers#it are not ging to fix the underlying issues at all.
here is a place to read: http://rawze.com/forums/showthread.php?tid=7&pid=9#pid9

* Also do a full turbo inspection.. take the actuator off it and inspect the turbo. here is a video on that...
<iframe id="lbry-iframe" width="560" height="315" src="https://odysee.com/$/embed/isx-inspecting-and-replacing-your-turbo/bd980df4368c3470544b0cf02c446df94ca24ebb" allowfullscreen></iframe>

-- and read, read, read and learn how to solve those problems for yourself, because no one else is going to do it for you. Darates and emissions issues are caused by engine problems, those exhaust components getting clogged up and causing power loss and derates are the result of the engine in poor health. it is not rocket science, but someone has to go thru the steps to do a full tune-up on it and check everything out nose to toes... actually you should have done that the day you got it instead of running off and wasting your money and time like that.

-- Also want to perform an overhead valve adjustment on it, inspect the overhead cams, and followed by an injector leak test on it too...




* Also, register your engine ser# on cummins.quickserv.com... everything you need to know .. parts, engine drawings, manuals, procedures, troubleshooting, maintenance, etc.. is on cummins website for free.

-- as far as the turbo goes.. Once you get a datalink adapter and insite going, you can replace and calibrate it yourself. Inspect it, like shown in video above.. any questions, post them or a video and ask away.. that is what this place is for. ... and if it is actually bad, then most people on the forum here use YTS turbos out of griffin, GA...one of the very few places that can be trusted to have the turbo rebuilt. Usually costs about half what the red engine maker wants for one.


We live in an age of trucking that if you don't learn to turn a wrench on it and solve those kinds of issues, then your trucking business is doomed to be a slave of that system, keeping you broke all the time while the CEL lights, darates, etc. drive you insane.!.

You don't buy a used house and call the most expensive plumber in town whenever you find a dripping faucet or the toilet clogs up... they are going to sell you a new toilet and replace the whole sink vs a plunger and a 3-cent o-ring. ... just like that plumber, those stealers$its are professionally trained to get you for all they can. ... You would not do this at your house ... why would you do that to your truck>?


RE: inconsistent running - Magard - 10-05-2020

Running it that high of rpm could have you fighting the gear down protection mode. Does it act up if you keep your shifts bellow 1700rpm?


RE: inconsistent running - bendor - 10-05-2020

As I said this ISX thing is new to me. I know nothing about them and not to mention at the time I took this in we were so busy I could not keep up. So thats the reason I took it in . As far as working on my own trucks I have worked on trucks for almost 40 years now and about the only thing I usually don't due is major component replacement. In other words major engine or transmission rebuild or replacement. I would say that if i have been able to work in the heavy equipment and truck industry for this long at my fathers company as a start up in 1976 until 1990 when I started my own company and am still self employed at that I must be doing something right. Wouldn't you agree? Computers are still relatively foreign to me especially when it comes to engines.I have already read about the egr tune up and that is on my to do list, as well as turbo inspection to see if it is bad which I am sure it probably is by the noise and vibration it had. What caused it to fail is beyond me at this point until I get into it. It is a cummins rebuilt. Maybe it is just a bad rebuild and failed?! Some times we all have to go thru a learning curve on new things. Also when hooked up to the computer it is not showing any fault codes. So what do you do there? I have already read about the ghost codes!


RE: inconsistent running - tree98 - 10-05-2020

Do you know if its demandated(deleted)?


RE: inconsistent running - bendor - 10-05-2020

yes it acts up if you keep the rpms low. tried that and yes I believe it is 100 % emission compliant it came from a kw dealer and everything seems to be there. thats the other thing its like you said when int acts up. It may not do it for a day then it acts up just doing it more and more.