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Last year we experienced a Cummins engine "de-rate" event with our Diesel Exhaust Fluid (DEF) emissions system. For those unfamiliar "de-rate" means eventually being limited to 5 miles per hour or less...and in consequence calling a towing service. We were much more fortunate than some experiencing such problems as software updates and recalibration of a pump component resolved our immediate issue, but now we approach each trip with apprehension and heightened anxiety. Last year FMCA undertook to survey Members on failure/repair issues associated with the DEF emissions system. Five months later no information has been released to Survey respondents, nor to the Membership. I did find the EXECUTIVE BOARD MEETING MINUTES of last December (12/2/2021) reported that "Linda Burdette, Chairman of the Governmental and Legislative Affairs Committee, provided an update on the Diesel Exhaust Fluid (DEF) issue. She stated that the committee is in the process of collecting data on issues that the members are having. A survey was sent out to 23,000 FMCA members who own a motorhome with a year of 2008 and later. Comments are being collected from the responses, and the survey data will be reviewed once the survey is completed. She reported that there are several theories about why the issues are happening. Once the data is analyzed, committee members can reach out to Cummins with details on the issues and try to negotiate a fix for the issues." Recently I asked Rett Porter, our FMCA President "Could the preliminary analysis, along with an updated plan of activity, be quickly distributed to members waiting for this information? Please consider posting on the FMCA website and notifying members how to access via email." Mr. Porter replied " Please be patient as I’m not going to release any information at this time." I think those of us with the risk/exposure to this issue deserve to be updated. I worry with every trip that my engine will "de-rate" again, and that we will be less fortunate than before and subject to a protracted and expensive repair. If you also are concerned please contact Mr. Porter at rporter@fmca.com.

Hi all, I have a Nexus 40D on order with an ISB360 and an Allison 3000. Can anyone with a similar sized unit and drivetrain attest to the pulling power for a toad? I’m looking at pulling an suv weighing 5,000 or 6,000 lb. Want to make sure I’m not overloading the drivetrain from a usability standpoint (I know I’m within max parameters). Thanks, Shawn

I have a 2009 Forest River Berkshire Class A diesel pusher with a 6.7L Cummins that keeps overheating. In the past month I have: First, Had the rear radiator blown out with air and then pressure washed. Lots of black filthy water came out. Still overheating. Then: 1. Had the Turbo replaced ($3400 rebuilt part-if you get one BE SURE it comes with the actuator) and the exhaust fixed where it had come loose and had it re-milled to fit better. $2800 labor. The tech showed me the turbo and it was definitely jammed up and not able to spin freely. Drove away, still overheating. Returned and then: 2. Had thermostat replaced $551 Drove away, still overheating, took it back third time and then: 3. Had a re-gen done on the catalytic converter 4. Replaced the air filter - it was filthy and jammed up with dirt Did all that at a place called Ross Point Truck Repair in Post Falls, ID. Drove away, still overheating. SPENT 4 WEEKS THERE!!! STILL NOT FIXED!!! 5. Had the inner cooler or CAC sprayed out with water Took it to Western States in Spokane WA and they hooked it to the computer and said it was not showing any codes. If I downshift all the way to 3rd, 2nd or 1st on my Allison transmission, and get the RPM's up to like 2700-3000, it still gets hot but doesn't overheat. Of course, I can only go like 30-45mph. Doing lots of mountain driving in the next week. My wife and I travel for work, so if we are stuck somewhere not moving we are losing lots of money. A few folks have suggested the water pump. Another guy said maybe it's a sensor, but it mainly overheats on big hills. ALTHOUGH, it has overheated on flat ground towing the car about 15 minutes in to the trip. Our manufacturer says we should only tow 5000 lbs, our car is 6000, every mechanic I have talked to says the Cummins 6.7L should tow 10,000 lbs with no issues. We have had this rig since Oct 2017 and towed the car at least 7000 miles with no issues. It's not losing any water when it overheats. Engine oil level looks good. Transmission fluid is clear, full, and does not smell burnt. ANY IDEAS????

I need to replace my serpentine belt on my 2013 Palazzo with Cummins B6.7 engine. Has anyone done this. It looks like the radiator needs to be removed to gain access to the engine. Any ideas?

Had this on a personal thread but thought I would share, hopefully may help others. My system is a CAPS II, which has a common rail for high pressure fuel, ie the Gear/High pressure pump does not have 6 individual lines to each injector. Coach has a Cummins ISC 8.3L 330hp questions, (Engine S/N 46386599), , quickserv info. for my specific engine says it's a CAPS II. So, I've edit my original post into more of a statement than a question, please see later post with Cummins Common Rail fuel flow info. attachment Having some recent stalling/engine stop, no start problems. Luckily it was at the house! Many online, say it's the lift pump! None of the forums describe if the "lift pump" is the what I consider the prime pump or possibly the "lift pump" is a section of the CAPS II pump. Anyway, trying to "fix" this myself and decided to ADD an AirDog II 4G into the equation and remove the prime pump behind the ECU cooler, could be a good plan or possibly unnecessary. Figured it was cheaper than a tow and a Cummins bill. AirDog is basically a inline pump with it's own primary/secondary filter, and also removes "air" from Fuel, no magic magnet thou. Fuel flow: (Please reference attached pdf file with pics) Line 1: Tank to AirDog in side compartment on RV, Monaco relocated both Primary/H2O separator and Secondary to side compartment. I chose to put AirDog in place of the original primary. Line 2: Airdog to rear of engine fuel manifold/port Line 3: rear of engine fuel manifold/port to ECU Cooler Port In Line 4: ECU Cooler Port Out to CAPS II (Gear Pump!), #19 on diagram Line 5: CAPS II (Gear Pump!), to Secondary filter Line 6: Secondary filter to CAPS II (High Pressure portion), into #16(#2 port). Fuel returns from rail to back of engine fitting/ fuel manifold to enter into fuel inlet flow/return to tank. I've removed the prime pump (only ran for 30 seconds on key on) that was behind the ECU Cooler (see below), it was plumbed in parallel with the ECU cooler. I believe it's stock purpose was only a "prime" and then after engine was running, fuel is "sucked" thru fuel system via. CAPS II (Gear Pump!), . Since adding AirDog, I figured it was unnecessary and also had a check valve (ECU Cooler IN) that caused issues for some. Removed Check valve also. Hopefully I don't have hard starts without check, AirDog hopefully offsets that issue. PS 5 separate hose (Line #2-#6) sections with 12mm to Push Type 1 connector, Push Type 2 connector 2, and Banjo fitting have been replaced with 12mm to #8 JIC male end and #8-1/2 hose/fitting. Old hose was a mix hard plastic, some was rubber. DickandLois Reply: Gglenn, Just took the time to look at threads that cover you engine and some fuel issue. You have been reading the, but the second link is in a different thread first one and might prove helpful. http://community.fmca.com/topic/7186-cummins-isl-and-isc-engines-with-caps-fuel-injector/?page=2 http://community.fmca.com/topic/9625-cummins-caps-system-redesign/ I will be reading your information over the next few days to see what might be helpfull. Rich. More from me. He's doing something very similar to my plan other than he is putting the pump up front at the tank vs. just behind the rear tire bay in my plan. So, my plan AirDog will have to work "harder" in a prime or filter change situation, but it's also designed for a tough life. Much more robust design than the stock "lift" pump. Diagram shows the 2 separate "pump" areas in the single unit, the plumbing runs to in the CAPS II pump; ie one IN/OUT (7, 9 in diagram), (This is the Gear pump) which is also before the secondary filter and one IN to the high pressure pump unit at the end of the fuel loop (11 in diagram), after secondary filter. (This is the high pressure pump) 13 is the high pressure out to rail. The lift pump is a separate unit, runs for about 30 seconds on key on, I will call it a prime pump. So, the stock pumps are Lift Pump, Gear Pump, then High Pressure Pump. Lift pump is the small cylindrical pump behind the ECU cooler, Gear pump and High Pressure are in the same upper unit. Found these attached pics on quickserve. Gives the Fuel Flow path on the standard cummins config, obviously this gets tweeked when placed in the various coaches. Diagram is hard to read, but the text (see attached) shows each part of the fuel path. DickandLois Reply: The Diesel fuel is used to cool the injector pump, so more fuel is supplied then used. The Fuel tank acts as a heat sump, that removes heat by spreading it out in the fuel before it is recycled through the engine again. NOTE ! As the fuel is used the ability to cool the fuel is always decreasing. The key to maximum fuel economy is a fuel tank that is half full in hotter temperatures. Cool fuel increases MPG what pressure range? Do not work around a diesel engine with a possible high pressure leak when running. Clean the area well, start the engine, stop after a few seconds where is the area wet with fuel - that is the general location of the leak. The pressure are high enough to cut off a finger or kill if the wrong area is exposed to these pressures. Cummings engines, deliver around 18,000 psi of pressure. The Bosch VP44, which is able to produce 23,000 psi of pressure. *In today's diesel engines, fuel leaves the injector at 30,000 psi. Note. The ISC fuel return line(s) run under the valve cover and do leak at times, this will make the engine appear to be making oil as the fuel mixes with the engine oil. Not Good !! ISC is a real good engine over all, but like I said it does have its weak points. PS 5 separate hose (Line #2-#6) sections with 12mm to Push Type 1 connector, Push Type 2 connector 2, and Banjo fitting have been replaced with 12mm to #8 JIC male end and #8-1/2 hose/fitting. Old hose was a mix hard plastic, some was rubber. Good plan - the OEM hoses do not like the Bio fuels. Keep all in the loop, Rich Cummins_AirDog_CAPSII_ECU.pdf Cummins_CommonRail.pdf Lift pump move.pdf

We have a 2002 Monaco Diplomat 40PBT with the Cummins ISC engine. Last night on the way home from a trip, it died while driving. It had been running fine with no issues and without warning, the dash chimed, the lights on the indicator panel all went out, engine died and lost power steering. I was able to coast it to a safe spot. Though the engine stalled, the generator continued to run fine. We checked all the fluid level, rechecked the sliders, checked the battery voltage and everything looked fine. Both the house and chassis batteries were fully charged, so it didn't appear to an alternator issue. We still had over 1/2 tank of fuel. The fuel filters and fuel/water filter had all been changed within the last 1000 miles. We tried to disconnect the batteries and let it sit for a while then try to start it up. Nothing. No chimes or lights on the dash when the key was turned on, it was simply dead. Fuses and everything looked good. We finally resorted to having the coach towed home - ironically, it had died turning into our community, so the tow was about 300 yards! I tried it one more time to see if she would power up and nothing as before. This morning I went out to the coach to get something and tried to start it up. She started right up and purrs like she usually does. Everything seems to be fine this AM. I haven't driven it yet though. Any thoughts or ideas on the cause? Not feeling comfortable with the idea of driving it without knowing what happened. While doing some research online this morning, I saw two references to issues similar to this where the owner stated a 'weak relay' was changed, but no indication of which relay it was. Thanks in advance for any help!

Hi folks, Traveling north bound on I-5 about an hour south of Eugene OR on Nov 21 2014. Engine began to run very rough and no power. Took an immediate exit ramp and called Cummins, they said to limp in or haul. I chose the second option. 2009 Country Coach Magna with 49,164 miles. Nov 25, Andy at Cummins Coach Care called to say we have a dropped valve. I haven't yet had any conversation with Cummins to determine whether there may be a warranty. I do not have extended warranty. Bought the Coach from Premier RV in Junction City March of 2013 with about 20,000 miles on it. Perhaps someone out there could provide advice as to who to talk to and how to proceed?

As a newbie to RVing I am slowly rehabilitating a 1993 Aerosport by HMC, 34' W/ 250 Cummins. Transmission code on Allison MD 3060 is d-1, 2-1, 1-2. I have an appointment with Cummins dealer in three weeks, could not wait that long, called Freightliner, they had a tech on it in 30 min. I called the Allison dealer that installed the new ECU for the trans. and they said it is not a transmission part, but an engine part, Freightliner says it's a Allison part. Help! And is the throttle position sensor on the motor or at foot throttle? By the way, the coach drives just fine, but has "service" illuminated on shift pad. Any help would be appreciated, thanks.

I am looking at upgrading our diesel pusher (2004 Endeavor with 330 Cummins). I am finding good prices on 2008/2009 coaches, but am concerned about the cost of emission equipment maintenance. Would one of you experts out there be able to give me advice about purchasing a 2008/2009 versus one of the newer DEF burning Cummins engines? I don't want to make a big mistake....

We spent Sunday night at the Wal-Mart on the north side of Tucson. Monday morning we were out just after rush hour. Making the turn from traveling southward from Oregon, we now turn into the sun in the early morning, heading east toward Texas. Traffic through Tucson on I-10 is heavy but not as bad as some city driving. About 30 miles out of Tucson the traffic begins to thin out and travel becomes easier. Tucson isn't far from the eastern border of Arizona so we are quickly into New Mexico and the switch to Mountain Daylight Time. Our day is suddenly one hour shorter which adds some incentive to keep the wheels turning. Travel is relatively easy as we pass many little dots on the map, small towns in a sparsely settled part of the country. The passage over the continental divide is as easy on I-10 as anywhere in the US. If there wasn't a sign you would not suspect that you have passed over the divide. We've never stopped to see the THING! We laugh about it every time we see all the billboards and maybe some day we'll pass by here on a more relaxed schedule and make a stop just so we can see the THING. Las Cruces is the largest town on this stretch of I-10 until we reach El Paso. I-25 joins I-10 in Las Cruces and the traffic increases, more cars and lots more trucks. This is the warm up for the passage through El Paso. There is a loop highway around El Paso and the traffic is lighter but we seldom take that route. Looking at a map, we should make that the regular route through the area but it seems that I-10 just holds on to us and we stay with I-10 through the city. At Las Cruces the I-10 turns southward and it continues right along the southern border of the US south of El Paso. Looking over the Rio Grande River in the area, you can see the mountains of Mexico. We began to encounter scattered rain showers along this stretch and those stayed with us through the rest of the afternoon and evening. One of the bonuses of driving in rain showers is rainbows. Since we are driving east in the afternoon, the sun behind us shines into the rain shafts ahead and we see some specatcular rainbows against the dark sky of the next rain clouds. The colors are really vivid when there is a dark sky to contrast with the rainbow and we thoroughly enjoyed a variety of views during the afternoon and evening hours. Traveling east, I-10 joins I-20 at its western end at mile marker 186 near the town of, well there isn't a town anywhere near. Kent is seven miles west of the junction so I guess that counts. It is about this point that we transition to Central Daylight Time, losing another hour of travel time. Staying with I-10 we continue on to Fort Stockton. Our first choice for a campground is no longer in business so we continue on through town to a one-time KOA, now Fort Stockton RV Park. It is just off the highway on some terrible road that only gets worse as you enter the campground. We arrived well after dark and had to pick our own site from the two or three that were available. We picked our way along the muddy roads to find a site that would work. Louise helped position the coach by letting me know when to stop to stay out of the road. The site looks like the toad is still in the roadway behind us but it is a wide roadway. In the morning I could see that it really was clear, what looked like road was just a muddy rocky part of the site. Clearly this was not a deluxe site. It was quiet and dark and we slept well, got showers and emptied the gray water tank before we left in the morning. We woke to the sounds of rain on Tuesday morning as a series of showers passed over us. A check of the radar showed that we should take advantage of the brief break in the storm to disconnect and get underway as a more steady rain was approaching us from the south. Back on I-10 we drove in a steady rain for about two hours before breaking out into sunshine. We made a stop for fuel at the Tres Amigos quick shop. I'm finding that stopping at small fuel stations has a fun side. There was a work crew at this one, filling up their trucks. One of them struck up a conversation and expressed his appreciation for our motor home. He had time for half a dozen questions before his tank filled. Diesel at $3.599 looked pretty good for the area but I got only 35 gallons which would get us into San Antonio where I expected cheaper fuel. We would get into San Antonio before nightfall. San Antonio would be an overnight stop for us. About an hour down the road we pulled in at the Segovia Truck Stop and filled up with diesel at $3.399, Saving 20 cents a gallon on 75 gallons amounted to a savings of $15 from what it would have cost at the Tres Amigos. We didn't see fuel any cheaper than the $3.399 for the rest of our trip until we pulled into the Wal-Mart in Edinburg. Thanks to Gas Buddy for helping us find this bargain. We pulled into the Cummins Southern Plains on I-35 at 4:15 in the afternoon, checked in and parked for the night in front of their shop. We unhooked the toad and backed up to the building. We were parked between the building and the I-35 access road, less than 300 feet from I-35. When local traffic on I-35 slows down it is quickly replaced by the over the road truckers. The whine of truck tires is nearly constant through the night. The next morning we turn over the keys and head for the Cracker Barrel next door. After breakfast we return to the motor home and relax waiting for the service tech to show up and run us out of our home. We've been making this stop a regular for many years. It is a last service stop before we park the motor home for the winter. I like to park with fresh oil and clean filters for the engine and the generator, ready for the next season of travel. No matter what direction we are traveling we'll usually come through San Antonio and since this shop is just a few miles north of I-10 and on I-35, we manage to be near it almost every year. Purely by coincidence our best friends were at Iron Horse RV just 5 miles north. After a series of phone calls, we decide to do lunch on the River Walk together. We picked them up and spent a pleasant afternoon together. The BBQ at the County Line Restaurant was good and the walk was welcome exercise after four days of near constant driving. We enjoyed the shops of the Little Village and the fun of watching the birds and the tourists. As we were returning to the car our friends got a phone call from the repair shop, their replacement air conditioner was installed and working. When we returned to Cummins we were told that they had discovered a leak in the gaskets on the exhaust manifold. I asked if they could be replaced and they gave me an estimate. I authorized the repair realizing we wouldn't have time to make the 200 mile drive to our south Texas home that afternoon. We would be a day later than we had hoped in returning home. We called to let our friends know. We decided to join them at Iron Horse after our repairs were completed. I had noticed some water leaks in our new windshield when we traveled through the rain showers the day before. They were just little trickles but they shouldn't be there. I had the windshield re-sealed at Iron Horse late in the afternoon. We would overnight there, pay the bill in the morning and be on our way south in a two coach caravan with our friends. Thursday morning we left Iron Horse at 9:00 . From I-35 we take the I-410 loop south to I-37 which is the Interstate route to Corpus Christi. The ramp to southbound I-37 was closed so we had to divert onto I-37 N and do a U-turn which added about 5 miles to the trip. US 281 departs I-37 where the interstate turns southeastward. We stopped in George West for a quick lunch stop. Then we were on the road to Edinburg, Texas, our winter home. We parted ways with our friends at Edinburg. They wanted to stop to fill up their tank at Flying J. I had decided to get diesel at the Wal-Mart since we also needed some groceries. Louise would shop while I filled the tank and added the stabilizer to the fuel. Diesel was $3.329 at Wal-Mart. Our friends joined us for dinner at our campground that evening. Home at last!

I received a free one year membership in the Cummins Power Club. I now have a request to renew my membership for another year. I am asking if there is any benefit to this club. Thee are no Cummins dealers in Tucson, the nearest is in Phoenix. There are so many "clubs" an RVer can join, I am looking for feedback if any of you found value in the Cummins Club.

I have been dealing with increasing oil level in my Cummins ISC-350 engine. I had oil on the TOAD, high oil level, and a full Slober container. The unit has twice been diagnosed and serviced by Cummins Bridgeway. The first solution was to install a new "Fuel Accum Mod #4025319RX" at mileage 62842. I returned the MH at mileage 63696 with the same issues. The second solution put in 6 new fuel injectors and removed the Slober container and tube. It appears the slober port has been plugged. Present mileage is 67770 and all conditions except for the full Slober container have returned. Oil analysis on the first two service appointments showed fuel in the oil. Looking for suggestions for the potential source of this problem. I am throwing out a lot of money on oil, filters, and service. So far I am not getting the problem solved.

Purchased a 2012 Holiday Rambler Ambassador. At various speeds, motor home begins to surge (bucks) as I drive down the road. Does anyone else have the same problem? If so, have you been able to rectify it? Two trips to an International service center and two attempts to reprogram the transmission have not worked. Any suggestions other than constantly "staying on" International and Navistar would be appreciated. Clyde

I am new to diesel pushers (and class A coaches in general) but have jumped in with both feet!! I have just purchased a 2008 Gulfstream Tourmaster 40B coach with the Cummins ISL 425 HP engine on a Freightliner chassis . The coach has been very lightly used with only 16k miles and 40 generator hours. When first started, and for 5-15 minutes afterwards, the radiator fan cycles every 5 seconds or so between gale-force wind with lots of noise and almost no air or noise. After everything is completely warmed up it seems to behave. The engine temp seems normal - around 190°. Other noises that remind me of a bad bearing (squalling/grinding) are barely audible as the fan cycles, but with no experience with big diesels these may just be normal. I could probably make a recording of the sounds and post it if it would help. Can anybody put my concerns to bed, or do I need to find a Cummins shop before the fan screws itself through my $$$ radiator? We're looking forward to meeting all of the great folks as we begin to venture out from our corner of the country. 10 years from now we may be 8 year full-timers!

This is a shout out to Brett Wolfe. We went in for maintenance at Cummins West in Avondale (Phoenix), AZ today. In a post several months ago, Brett had suggested replacing the belts on the engine and saving the usable used belts as back up in case a belt breaks. I asked the service representative to replace the used belts and save them for me. We were having the generator serviced at the same time. In the discussion the service rep asked if I wanted the belt on the generator (7.5 KW Onan) replaced also. I thought, "If it's good for the engine, it has to be good for the generator." So I said to replace it also and save the old belt for me. Actually, I didn't even know the generator had a belt. Who knows what is in that big green box? When the job was done, the service rep gave me the belts from the engine and then showed me the belt that came from the generator. It was missing an inch of the inner notched material of the belt. The only thing holding it together was the strong continuous strip on the outside of the belt. Some additional inner material was peeled off the outer belt but still hanging on. It was just a matter of time until the belt derailed and we had generator failure. With temperatures in the low 100's, we really needed the generator to keep the motor home livable while driving. So thank you Brett. Your advice saved us a delay or more!