Last Dance at 1.2 Million Miles - 3216

[JKBowman]

Hi, Gang. :blush:

Here's the current fault code.



The truck (2013 T660 w/ ISX15 CM2250) just came out of the KW shop in Jacksonville, FL. While there she got a new EGR cooler, a new DEF pump, and about $700 worth of A/C electrical troubleshooting. The bill was $8,896.63 \o/

Engine light came back on 5 miles after leaving the shop. I returned to KW. The mechanic said I had two codes which he quickly cleared. One was a sensor error (that's all I know about that one) and the other was high crank case pressure. He suggested that I keep driving and return if needed. Unfortunately, the engine light came back on while taking the exit for Daytona (home). That's about 100 miles away from KW.

This code appears to be NOx sensor related, but that's about all I can say about it.

I need to avoid opening a new ticket at Kenworth if at all possible.

Thanks in advance for any replies!

[Rawze]

I could think of a whole lot more things to do with almost $9,000 dollars than giving to the stealers$it in return for a half-arssed repair.

What you have done is make A BAD INVESTMENT! ... You spent $8,800 dollars so that your truck can go a couple hundred more miles? and be broke down again -- that is no way to haul freight,.. you would have to charge your customers $50 a mile to maintain that kind of business strategy... That is the absurdity that I see there,.. and for me -- NO THIS IS NOT ACCEPTABLE IN OUR TRUCKING INDUSTRY!!!

Why was the EGR cooler replaced?

Have you pulled the DOC and DPF and taken pictures of their faces?, then had them baked, de-ashed, and flow-tested?

Assuming for a moment that the EGR cooler WAS leaking coolant...

* the engine oil needs replacing due to coolant contamination because it was getting into the cylinders.

* The DOC may be toast, due to coolant washing out its precious metals.
* The DPF may also be toast due to coolant washing out its precious metals.
* Same for the SCR element, depending on how long the truck was driven with a leaky EGR cooler.

* Any NOx sensor that is more then 200k miles old (or equiv engine hours) need replacing.

* ALL of the piping for the EGR circuits needs to come off and be cleaned out, including the EGR valve.

* ALL of the intake and egr sensors need inspection and cleaned or replaced.

* (depending on how long the truck was driven with bad egr cooler) The turbo exhaust impeller and VG blades inspected for excess wear from dried chunks of coolant going through the turbo.


NO STEALERS$IT IS GOING TO BOTHER TO DO THE ACTUAL THINGS IT TAKES TO PROPERLY MAKE THESE ENGINE RUN -- THEY ARE COMPLETELY USELESS RIP-YOU-OFF MORONS WHO DO NOTHING BUT TAKE THOUSANDS AND THOUSANDS OUT OF YOUR WALLET AND MAKE HALF-ARSSED REPAIR JUST TO GET YOU OUT THE DOOR!!!!!!!!

[Rawze]

If you have 1.2 million miles on a CM2250 engine, you have been a VERY LUCKY person. -- most of them do not make it much past 700k.

Were the rod and main bearings done at 800k miles? -- If not -- THEN YOUR DRIVING A TICKING TIME BOMB!! and that thing is well due for an inframe at this point so that you don't loose the whole engine with a huge hole in the side of the block, no warning whatsoever, because of a wrist pin failure.

Jsut because someone "thinks" what they have is somehow going to lasts forever does not mean it will... those people who drive their engines for that many miles and just ignoring these types of warnings, almost always regret the hell out of it later on.

Just putting this out here,.. seen it way too many times.

[Hammerhead]

(08-08-2019 )Rawze Wrote:  Were the rod and main bearings done at 800k miles? -- If not -- THEN YOUR DRIVING A TICKING TIME BOMB!! and that thing is well due for an inframe at this point so that you don't loose the whole engine with a huge hole in the side of the block, no warning whatsoever, because of a wrist pin failure...

Please explain the wrist pin failure - rod & main bearing correlation.
I can't explain this properly, and I'm looking for someone to help me unscramble the thoughts into words.

[JKBowman]

Thanks for the reply, Rawze. Hi, Hammerhead.

There's a lot to unpack here, but for brevity sake (I'll try) let me say that I've been following the advice I got from Chamberpains in this old thread.

I had new main bearings rolled in about 40,000 miles ago. At the time my mechanic inspected the DPF for packing and said that it looked good. He also inspected the top end and had a similar positive opinion on that. The owner of the shop literally went on to say, "A rebuild couldn't hurt, but at this point I think I'd just be taking your money." I was skeptical of that, especially given the number of miles, but my Blackstone report was also very positive. Without the money in my pocket for a rebuild and nobody willing to loan more than $15,000 toward it (despite good credit) there wasn't much left to do but keep driving and keep saving - or at least try.

I took her to Kenworth because 1) two independent shops had tried to diagnose the electrical problem with my bunk A/C and failed, 2) an engine light was on again (DEF Pump) and I'd already been in an small Wyoming shop for that, and finally 3) during my most recent tour, which I had just finished, I started to notice a minor coolant leak while not finding anything on the ground. I figured why not get it checked out.

Rawze, I suspect you may be right that taking the truck to KW was a bad business decision. It usually is. But I thought it was logical enough at the time. We were home. They were there. Downtime would be limited. I knew they had the wherewithal to fix my problems.

When the first quote came in, that one smaller than the final, it hit me in the gut but my wife and I both felt like the truck was worth saving. In retrospect, that may have been our biggest error. It may be that we shouldn't have tried to repair anything with anyone. Seriously. Maybe that should have been the end. But life goes on. This is where we are and I have to move forward.

First things first. I can't make any decisions or move forward with plans for anything until I figure out what's going on with this code. If anybody has any info on it, I sure would be thankful.

[Rawze]

(08-08-2019 )JKBowman Wrote:  Thanks for the reply, Rawze. Hi, Hammerhead.

There's a lot to unpack here, but for brevity sake (I'll try) let me say that I've been following the advice I got from Chamberpains in this old thread.

I had new main bearings rolled in about 40,000 miles ago. At the time my mechanic inspected the DPF for packing and said that it looked good. He also inspected the top end and had a similar positive opinion on that. The owner of the shop literally went on to say, "A rebuild couldn't hurt, but at this point I think I'd just be taking your money." I was skeptical of that, especially given the number of miles, but my Blackstone report was also very positive. Without the money in my pocket for a rebuild and nobody willing to loan more than $15,000 toward it (despite good credit) there wasn't much left to do but keep driving and keep saving - or at least try.

I took her to Kenworth because 1) two independent shops had tried to diagnose the electrical problem with my bunk A/C and failed, 2) an engine light was on again (DEF Pump) and I'd already been in an small Wyoming shop for that, and finally 3) during my most recent tour, which I had just finished, I started to notice a minor coolant leak while not finding anything on the ground. I figured why not get it checked out.

Rawze, I suspect you may be right that taking the truck to KW was a bad business decision. It usually is. But I thought it was logical enough at the time. We were home. They were there. Downtime would be limited. I knew they had the wherewithal to fix my problems.

When the first quote came in, that one smaller than the final, it hit me in the gut but my wife and I both felt like the truck was worth saving. In retrospect, that may have been our biggest error. It may be that we shouldn't have tried to repair anything with anyone. Seriously. Maybe that should have been the end. But life goes on. This is where we are and I have to move forward.

First things first. I can't make any decisions or move forward with plans for anything until I figure out what's going on with this code. If anybody has any info on it, I sure would be thankful.

SPN:3216,FMI:20 = cummins fault code 3748. -> ftertreatment Intake NOx Sensor - Data Not Rational - Drifted High. An offset in the intake nitrogen oxide (NOx) sensor reading has been detected.


I.E.> A bad, leaking, or improperly installed NOx sensor at the back of the turbo... OR someone has replaced it with a fake sensor, or Chinese after-market one. It is basicly complaining that the sensor is not reading ZERO with engine off, during self test ... OR it is not changing at all when engine is revving up and down and under loads.

It will not clear this fault until you get the engine and exhaust 350+-F degrees, drive around a bit under varying conditions, and the self tests that were failing pass their checks again.

[Rawze]

(08-08-2019 )Hammerhead Wrote:  

(08-08-2019 )Rawze Wrote:  Were the rod and main bearings done at 800k miles? -- If not -- THEN YOUR DRIVING A TICKING TIME BOMB!! and that thing is well due for an inframe at this point so that you don't loose the whole engine with a huge hole in the side of the block, no warning whatsoever, because of a wrist pin failure...

Please explain the wrist pin failure - rod & main bearing correlation.
I can't explain this properly, and I'm looking for someone to help me unscramble the thoughts into words.

when there is too much play (bearing wear) in the rod and main bearings, harmonics set in and cause the wrist pins to start to hammer on the rod bushings at the top of the rods. This wear is specifically at roughly the 5'o-clock position on the rod when looking at it TDC, perspective from the rear of the engine facing forward.

The rod bushings at the top of the rod are relatively-soft brass, and have no protection against this type of hammering or vibration. -- As they wear out, then it is steel on steel, and the top of the rod starts to eat into the wrist pin,.. overtime, the pin finally wears through, and the piston goes sideways in the block. <-- there is absolutely no way to detect this until it is too late.


There is a standing trend and clear pattern of this failure occurring for CM870 and CM871 engines that have not had their rod/main bearings changed at 800k like recommended here. The failures I have seen myself have all occured anywhere from 1.2 mil miles to 1.4 mil (one cm870 made it to 1.6 mil once though) miles on these engines. - There are not a whole lot of CM2250's and even less CM2350,s that make it anywhere near this mileage, but I can only assume they would have the same issue. Possibly though, the CM2350 may have this issue even sooner, and even sooner for the X15's, but only time will tell that one.

Some related info: -- I have seen a number of CM2350's with bad programs that were causing high detonation rates. This is mainly due to people using the factory injection timing, or worse yet, sometimes advancing it even further .. but have removed the EGR gas completely. <- The result is a high enough detonation rate to cause this same wrist pin hammering .. no one feels it or detects it. Engine seems to run smooth.

On those CM3250,s , so far, they all have failed with head gasket issues due to dropped liners (like I said, bad programming),.. and the brass is beat to snot at the top of the rods .. a failure was imminent,.. but in every case so far, it was a head gasket failure that happened first. <- I can only imagine that this will not always be the case, and there will be trucks that send a piston through the block with zero warning due to this, I just have not seen it yet.

Adding up 1+1 to get 17 ... LOL ... (just some thoughts here) ...

It seems clear that the CM2350's are a lot more prone to bad programming and this happening than the CM2250's or older lower comp[ression engines. <- makes me wonder if this is going to be a big engine killer for those X15's, especially tyhe high HP models with their 19:3 or 19:6 compression ratios.

I feel sorry for anyone who has an X15 if they have had a de-mandate done by someone not knowing exactly what the combustion cycle needs .. I see a lot of engine failures in their future.

Another related side-note: The wrist pins seem to be made of some seriously tough hardened steel,.. I mean seriously tough ... tool steel can't even hardly scratch one, it is that hardened, so one would think there is no way a wrist pin can fail and get sheered ... HOWEVER... They are only surface hardened, and are soft as butter in the center. I know this very well because I use old wrist pins for making things like collets, spacers, etc. (using my lathe). Once you get past that first 0.008" or so of that super-hardened coating, they are easy to machine.

[Hammerhead]

Does excess wear exacerbate this problem?
I assume it would, as with more wear the spacing increases, allowing more oil escape loss out the larger gap, thus reducing the supply volume & pressure via the oil rifle in the rods.
Puts a couple points into the 1+1=17 formula...

Basing this assumption on some of our maximum efforts of racing engines. We would deliberately build some excess tolerances to reduce mechanical resistance. We would build and install oil pumps that were capable of 80psi to compensate for the losses. They would never exceed 50psi because of the volume of losses, but supplied sufficient volumes to keep issues at Bay for our desired life acceptability.

***edited to add: NOT that I'm advocating for guys to shim their oil pumps up to 80psi!
Engine life acceptability of a dragster motor is approximately 16 miles!
DO NOT try this at home, even with adult supervision

[Hammerhead]

(08-08-2019 )Rawze Wrote:  Another related side-note: The wrist pins seem to be made of some seriously tough hardened steel,.. I mean seriously tough ... tool steel can't even hardly scratch one, it is that hardened, so one would think there is no way a wrist pin can fail and get sheered ... HOWEVER... They are only surface hardened, and are soft as butter in the center. I know this very well because I use old wrist pins for making things like collets, spacers, etc. (using my lathe). Once you get past that first 0.008" or so of that super-hardened coating, they are easy to machine.

Ah yes, the Hard Candy concept. Timken taper roller bearings (and I assume all others as well) use this same principal.
The idea is that the softer inner core can flex while the outter rigid shell maintains it's integrity. The theory is, that a hardened all the way through material source would shatter without a softer inner core to transfer the shock load to.