Well it wasn’t the fuel filters….(to make a short story long)

[Sand-dog]

OMG WWJD, five dollar mistake. because of you I’m now double checking my ISL 9 to make sure everything is tight and secure. I am so sorry you had to revisit this whole situation. Absolutely terrible what you went through. Thank you for all that you did and shared.

 

[Rich W.]

OMG WWJD, five dollar mistake. because of you I’m now double checking my ISL 9 to make sure everything is tight and secure. I am so sorry you had to revisit this whole situation. Absolutely terrible what you went through. Thank you for all that you did and shared.

Well fortunately you can easily access your motor to check such things.

 

[Neal]

@Rich W. are you the original owner?

 

[Rich W.]

@Rich W. are you the original owner?

No I bought it in 2020 with 16k on it. It was pristine then - not so much now (65k and counting). But…WOW, what a difference 8lbs of boost makes. I had the most wonderful day crossing Nebraska and Iowa ever (with boost as high as 32psi). All because this thing now runs as it should. Good enough for me. I’m simply elated that Truck Center Companies was able to finish the job that Floyds started and correct Floyds’ errors.

More on all that later - for now I’m just enjoying a beverage (or three) in a very nice, simple CG on the Cedar River in Iowa awaiting my appointment with HWH on Monday morning which will put me back on schedule, albeit with some unfinished business on the coach. But I don’t care - it ran so well today it was a joy and a pleasure driving and for now I’m just going to celebrate that.

Yes, these folks have my full confidence and endorsement. More on that later too.

 

[Rich W.]

I was just asked about the specific cause of the low boost/power condition that led to this whole conundrum and below is my response to that question:

The cause ended up being a damaged and disconnected air intake hose for the compressor which takes air from the CAC. Compressors used to take air from the air fiter assembly but somewhere along the line they changed over to supplying it from the CAC - maybe more pressure or volume? I don’t recall the reason. But the compressor supply hose is only 1” in diameter so it wasn’t a huge leak. Didn’t shut me down but did rob enough power to make the problem obvious.

Anyway that hose was damaged at some point (I don’t know when or how and unfortunately I neglected to ask for the old hose to examine it) and it was not even connected when it left the shop in Sidney. So Truck Centers in Lincoln replaced that along with correcting a half dozen other mistakes and omissions and now its running better than it has for a quite a while.

I don’t recall it having as much power as it does now, so the degradation of the hose was probably gradual because I didn’t notice it until I set out on this trip. But the difference was remarkable - from a max of 22 psi boost to 32psi. I could tell the difference before I was half a block away from the shop in Lincoln - it was like driving a different machine. Now I just have to get all the other stuff done that I was going to have handled in Nappanee.

Another clue beside low power was increased frequency of regens. This seemed odd but I failed to make the connection. It was due to the increased soot developed by insufficient air supplied during full throttle (max fuel) operation, which was more often due to decreased power.

So the moral of the story is that low boost is more than an annoyance and addressing it is something that should not be put off just because you're on a schedule. After changing fuel filters on the road (in hopes that was causing my low power condition) did nothing to improve things, my plan was to address it at or after Nappanee because I had a week scheduled there and I didn’t want to be late. Live and learn. I missed the whole week there and spent a lot of my coach improvement fund on an exhaust manifold, related parts, and lodging. Oh well - another costly lesson learned in the ownership of a DP.

 

[Bigblockyeti]

I'm also curious as to why the move from drawing compressor air from the air filter to downstream of the turbo? I have my guesses but it seems to me (and has been confirmed by this whole debacle) you end up making a less reliable power plant by doing so.

 

[Rich W.]

I'm also curious as to why the move from drawing compressor air from the air filter to downstream of the turbo? I have my guesses but it seems to me (and has been confirmed by this whole debacle) you end up making a less reliable power plant by doing so.

My guess is that the extra inlet pressure may benefit the compressor system, maybe allows for a smaller compressor or less run time, but it would have no benefit at idle, low throttle conditions, or deceleration, so……? Whatever but I agree, the fewer complications to the intake system, the entire system actually, the better.

 

[Rich W.]

I'm also curious as to why the move from drawing compressor air from the air filter to downstream of the turbo? I have my guesses but it seems to me (and has been confirmed by this whole debacle) you end up making a less reliable power plant by doing so.

I did a little more research after reading your post earlier this morning and this is not an uncommon problem - apparently chafing from clamps or zip ties, and rubbing on supports, as well as weakness in a 90° turn on the hose, can all cause this. And because it causes a relatively small leak (1” hose vs 4” inlet and outlet pipes) it just reduces boost enough to rob power, unlike a turbo boot that will about shut you down. There’s even a TSB on it for Navistar. Just another over-engineered complication we didn’t need.

Navistar version, same idea:

https://static.nhtsa.gov/odi/tsbs/2021/MC-10201757-0001.pdf

 

[Rich W.]

I'm also curious as to why the move from drawing compressor air from the air filter to downstream of the turbo? I have my guesses but it seems to me (and has been confirmed by this whole debacle) you end up making a less reliable power plant by doing so.

I guess it could be as simple as less and smaller diameter hose because the source is both under positive pressure, and closer to the compressor so cheaper. Personally I think its kind of dumb to have any more possible intake leak sources than absolutely necessary. I guess they don’t have high school auto shop anymore.

 

[Rich W.]

Well the issue with Floyds was finally resolved, although not during round one, and not exactly in a timely manner. Part of that is on me for giving them a chance to solve this at the lowest level and waiting for responses. But yesterday I finally talked to the right person and today it’s resolved.

From Floyds this morning:

Rich I went ahead and credited back all the labor you had spent with us here at our location which ended up being a little bit more than what you had spent at the following dealer. I thought it was only fair especially with how much you where inconvenienced with this whole situation, apologies that this didn’t go the way we would have hoped but I do hope you consider us in the future for your next repairs and we will do our best to make it right,

So I’m satisfied and while I hope this didn’t impact the mechanics that worked on it too much, I also hope everyone learned a little something. I sure did!

 

[Rich W.]

A little update - found a thread on the FB Ventana owners group and apparently its not all that uncommon to have the exhaust manifold on a 6.7 warp between 60k and 80k miles. Mine happened at 67k and I still think it was precipitated by the low boost condition, but this is a “known problem” for which Cummins takes no responsibility, naturally.

 

[Kevin D Pem]

A little update - found a thread on the FB Ventana owners group and apparently its not all that uncommon to have the exhaust manifold on a 6.7 warp between 60k and 80k miles. Mine happened at 67k and I still think it was precipitated by the low boost condition, but this is a “known problem” for which Cummins takes no responsibility, naturally.

Just because a problem can be observed, doesn't mean a cure can be engineered without serious redesign of all related components. So over time people learn about a problem. They quit buying them. The manufacturer moves on to a product that doesn't have that issue, and that's how quality evolves.
That is why there are "limited warranties " to limited the time they are liable. There is no limit to implied warranties (no warranty stated)! Hope you appreciate my lesson on the legal aspect of written warranties!!!

 

[Rich W.]

Its really hard to say how common this problem is, or if it has been corrected. If it was significant enough it would trigger a recall but apparently its not, and since its a higher milage condition, fewer people would be encountering it. But hopefully the fact that it is a known condition has brought some attention to correcting it. If it has been corrected, by a better design and/or better materials, my new one should outlast me, or at least my ownership of the coach. But I am growing a bit weary of known defects that can cause one to be stranded that are simply allowed to exist without correction or even comment from the manufacturers.

 

[Kevin D Pem]

I suppose you are admitting you are living the 3D life and tired of it!!!
So you must be ready for a new world eh???

 

[Rich W.]

I suppose you are admitting you are living the 3D life and tired of it!!!
So you must be ready for a new world eh???

The old one would do just fine.

 

[Wemustrv]

Experiencing lower than normal boost (about 25% below normal) I was grasping at straws looking (hoping) for a simple, cheap fix. I didn’t really think it was the fuel filters (only 2300 miles on them) but I had spares on board and it was a possibility, and being a cheap and easy rule-out I gave it a try. Naturally no improvement from that but of course I pushed on anyway. Other than long grades and initial acceleration the thing ran fine and I was able to easily ramble along at 65mph.

Until the grade headed east out of Cheyenne. That was a long pull at the top of which I had a flashing amber check engine light, immediately followed by solid amber, solid red, and complete and sudden shut down, all within about 30 seconds, barely giving me time to get to the shoulder and stop, and all the while temp and oil pressure gauges reading normal. So after sitting less than a minute, baffled, I decided I had to re-start the engine to avoid hot engine shut down issues and it started right up. I put it in gear and it ran although obviously severely derated. Fortunately we were at an exit, with a small truck parking area on the side of the accompanying on ramp.

I parked, kept it running, and plugged in my trusty Diesel Handheld code reader and found SPN 5862 FMI 9 - Aftertreatment 1 SCR Intermediate Gas Temperature - Data Valid but Above Normal Operating Range. There is lot of info on this including three “possible“ causes in the library, none of which were correct. I’ll paste in the long version at the end of this post for anyone interested. The only other code was SPN 110, FMI 31 - Engine Coolant Temperature - Data Valid but Above Normal Operating Range. This seemed to be a result of the shut down as my temp gauge read normal before, and also normal immediately after re-starting, but was pegged momentarily while the engine was stopped - the reason I immediately restarted it. Interestingly this code also seems to be a clue to the actual issue (high exhaust temp) - more on that below as well.

I cleared the codes (there was no code indicating de-rate or anything else - just the two codes above) and we decided to move on down the road driving it as easy as possible since all indications at that point were that it was operating normally - no overheat, no recurring codes, etc. This seemed to be just another spurious mystery emissions glitch, similar to what many others have experienced. We stopped that night at the Cabela‘s campground in Sidney NE, everything still seeming normal. But the next morning we had a loud, screeching exhaust leak, apparently opening up after everything cooled. It was exactly one mile to Floyd’s Truck Service (we saw the Freightliner sign on the way in to the CG) so we drove straight there and are still here four days later and will apparently be here most of next week.

The Cause:
The apparent culprit is a leaking CAC causing the low boost I was experiencing, which I found inconvenient but unfortunately didn’t recognize it as a condition that could lead to bigger issues. The bigger issue is that it led to a rich fuel/air ratio because the engine was getting less air than it should but the ECM was still feeding it full fuel, which was everything it could since I was climbing a grade under load. The result was a very high exhaust temp even though the engine temp was normal. This warped the exhaust manifold beyond any point of re-surfacing, and of course I need a new CAC.

The only other pertinent info is that I had to do a forced regen early in the trip and that seemed like it was too soon since the last one, and later caught the system in the act of several active regens. This seemed weird but I chalked it up to a needy emissions system. The actual reason was excessive soot due to the rich fuel mix, but of course I never made this connection early on, just like I dismissed the low boost as troubling but not significantly consequential. Live and learn…

So I called Nappanee, cancelled my week at Camp Newmar, which was the reason for this trip, cancelled a bunch of other plans, boarded the dogs locally and we are currently holed up in a Comfort In owned by the Love‘s next door and across the street from Floyd’s. We have the Jeep and the bikes and are trying to make the best of it while we wait for parts. The shop is very professional, capable, and accommodating and provided a lot of info on fun and exciting things to do when stuck in Sidney Ne. What fun!

The Codes:
Fault Code: SPN 5862 FMI 16 (4525)
SPN: 5862
FMI: 16
Aftertreatment 1 SCR Intermediate Gas Temperature - Data Valid but Above Normal Operating Range - Moderately Severe Level
Reason:
High SCR Intermediate temperature detected.

Circuit Description:
The aftertreatment SCR (selective catalytic reduction) temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment SCR temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link.

The aftertreatment SCR temperature sensor module is used to measure the aftertreatment SCR intermediate temperature and aftertreatment SCR outlet temperature. The temperature probes are permanently attached to the aftertreatment SCR temperature sensor module and can NOT be replaced individually.

The Engine Control Module (ECM) detected the aftertreatment SCR intermediate temperature was above 650°C [1202°F] for 60 seconds.

1. The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.
2. The engine will be shut down if the Engine Protection Shutdown feature is enabled.
3. Progressive power and/or speed derate increasing in severity from time of alert.
4. If the Engine Protection Shutdown feature is enabled, the engine will shut down 30 seconds after the red STOP lamp starts flashing.

The aftertreatment SCR temperature sensor module is mounted on the aftertreatment SCR catalyst.

1. To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2. The fault code status displayed by the diagnostic tool will change to INACTIVE immediately after the diagnostic runs and passes.
3. The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
4. The Reset All Faults command in the diagnostic tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

This diagnostic runs continuously when the engine is running and active regeneration of the aftertreatment diesel particulate filter is not occurring.

Possible Causes of this Fault Code Include:
1. Malfunctioning fuel injectors
2. Malfunctioning aftertreatment SCR intermediate temperature sensor
3. Contaminated diesel exhaust fluid

Fault Code: SPN 110 FMI 31 (2646)
SPN: 110
FMI: 31
Engine Coolant Temperature - Condition Exists
Reason:
The EGR valve was closed to reduce engine coolant temperature.

Circuit Description:
The coolant temperature sensor is a variable resistor sensor and is used to measure the temperature of the coolant of the engine. The engine control module (ECM) supplies 5 volts to the coolant temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature.

The Engine Control Module (ECM) detected the engine coolant temperature was above a threshold and closed the EGR valve to reduce the engine coolant temperature.

1. The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
2. Exhaust Gas Recirculation (EGR) valve operation will be disabled.
3. Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
4. Possible reduced engine performance.

The engine coolant temperature sensor is located on the thermostat housing.

1. To validate the repair, perform a key cycle, and leave the key in the ON position for 1 minute.
2. The fault code status displayed by the diagnostic tool will change to INACTIVE immediately after the diagnostic runs and passes.
3. The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4. The Reset All Faults command in the diagnostic tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

This diagnostic runs continuously when the engine is running.

When the engine coolant temperature nears the engine protection limits, the EGR valve will be closed to reduce the coolant temperature. This fault code is used as an information fault code, ONLY indicating that the EGR valve has closed. No malfunction has occurred to cause this fault code. Other engine protection fault codes will be active if the engine coolant temperature has exceeded the engine protection limits.

What is CAC? See below for what I found

 

[Rich W.]

What is CAC? See below for what I

Charge air cooler, otherwise known as an intercooler but I guess they needed their own name for it. Something like this: Northern Radiator | Freightliner Chassis Motorhome Charge Air Cooler - 38 5/8 x 27 5/8 x 2 7/8 (Extra Port)