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Gdoubleoo · 01-11-2022, 07:54 PM

So today I picked up my Motorhome from dealer where it had been sitting for about 3 weeks in sub zero Fahrenheit weather. Seemed to run fine , then about 20 minutes in my check engine light came on (orange) , my wife who had given me a ride and was following behind me said the Motorhome was putting a lot of black smoke out (Cummins 6.7, power glide chassis) after another 15 minutes the red check engine light came on about 5 minutes after that the Motorhome just stalled . I had noticed reduced power since the orange light came on . My def tank was just below a quarter full and had not given me any warnings about de rating. I pulled over and was able to get a hold of a Cummins dealer , unfortunately he only had the computer code reader up until 2013,. Mu unit is a 2020. Could the weather have messed around with the def system? What explains the black smoke and no warning except for amber and then red check engine light? After it stalled , I pulled over and could start it again no issues - but the problem had not gone away and would repeat itself a few more times before I could get it safely off the road. I suspect the def system - but not convinced. I cannot do a manual regeneration on my unit I think , but that is what may need to be done.

NevadaNick · 01-11-2022, 08:19 PM

The fuel gelled.

Gdoubleoo · 01-11-2022, 09:26 PM

the cummins mechanic that came out only had a code reader to 2013, and will bring a different (updated) one out tomorrow. He did use a 3rd party code reader and it gave a code SPN3936- SAE- After treatment DPF System. This would take me back to the DEF system? Would that explain black smoke, no def messages . Fuel is a bit suspect as well, it had burned 1.5 tanks of winter fuel since I purchased it with summer fuel in it in October. so there could have been a bit of summer fuel still hanging around.

saddlesore · 01-11-2022, 09:32 PM

Hmmmm.... Black smoke denotes a plugged air filter or bugger'd turbo.

Cincy Steve · 01-12-2022, 11:30 AM

2 thoughts:

DEF is 65% deionized water & can freeze, hence the tank’s proximity to the engine(heat).

Never entirely trusted truckstop “winter fuel” & judging by the empty fuel dope bottles stacked in fuel island trash bins, I have plenty of company. I add treatment anytime temps are continuously below freezing & make sure it has run through the Gennie & AquaHot, too.

bigb56 · 01-12-2022, 12:30 PM

I'm going with Nevada Nick, I think the fuel gelled. Contrary to popular belief, I believe smoke can occur during fuel starvation as the engine cannot develop sufficient RPM and turbo spool up so cannot completely burn what fuel it is getting and smokes. I say this because I have had diesels that smoke when the fuel filter was clogged and stopped smoking when replaced. Lack of DEF does not cause black smoke or driveability concerns other than computer related limp home modes. DEF also has nothing to do with dpf regeneration, separate processes.
Beware of mechanics who rely too heavily on codes, if the engine got starved of fuel there may be many codes resulting from the poor performance that point to items that couldn't do their job because of the lack of performance so they reported a fault to the ECM but they are not the root of the problem, just a symptom that will go away once the root is found. New fuel filters and some Diesel 911 may get you going again.

PS Did you check the air intake for critter nests?

Gdoubleoo · 01-12-2022, 01:12 PM

Thanks, we will check air filter. It is throwing a code 1922 DPF plugged, but you make a good point that codes can be faulty when engine is starving from multiple issues. The mechanic that is currently looking at it is not certified with Cummins to do warranty work, so he has to be careful to touch anything that can void warranty. I am still within 2 years of purchase and seems like I have warranty. Of course they can't tell me that for sure until they look at the unit. Which brings me to the frustrating part , they can't get it in to service for probably 10 days with certified cummins mechanics. If I get my current mechanic to replace fuel filters, and if he is able to get a re generation of dpf system to go, It might solve the problems? I have been told the def system is 4-7,000 dollars to replace depending what is wrong- then I better hold tight until certified mechanics can look at it. Suggestions are appreciated? thank you

bigb56 · 01-12-2022, 01:14 PM

Quote:

Originally Posted by Gdoubleoo

Thanks, we will check air filter. It is throwing a code 1922 DPF plugged, but you make a good point that codes can be faulty when engine is starving from multiple issues. The mechanic that is currently looking at it is not certified with Cummins to do warranty work, so he has to be careful to touch anything that can void warranty. I am still within 2 years of purchase and seems like I have warranty. Of course they can't tell me that for sure until they look at the unit. Which brings me to the frustrating part , they can't get it in to service for probably 10 days with certified cummins mechanics. If I get my current mechanic to replace fuel filters, and if he is able to get a re generation of dpf system to go, It might solve the problems? I have been told the def system is 4-7,000 dollars to replace depending what is wrong- then I better hold tight until certified mechanics can look at it. Suggestions are appreciated? thank you

hmmm, I wonder if a critter could've nested in the exhaust?

bigb56 · 01-12-2022, 01:17 PM

Quote:

Originally Posted by Gdoubleoo

Thanks, we will check air filter. It is throwing a code 1922 DPF plugged, but you make a good point that codes can be faulty when engine is starving from multiple issues. The mechanic that is currently looking at it is not certified with Cummins to do warranty work, so he has to be careful to touch anything that can void warranty. I am still within 2 years of purchase and seems like I have warranty. Of course they can't tell me that for sure until they look at the unit. Which brings me to the frustrating part , they can't get it in to service for probably 10 days with certified cummins mechanics. If I get my current mechanic to replace fuel filters, and if he is able to get a re generation of dpf system to go, It might solve the problems? I have been told the def system is 4-7,000 dollars to replace depending what is wrong- then I better hold tight until certified mechanics can look at it. Suggestions are appreciated? thank you

hmmm, I wonder if a critter could've nested in the exhaust? If you think about it, being stored in sub zero temps makes fuel and critter nests seem likely suspects, especially on such a new rig.

RonAz · 01-12-2022, 01:22 PM

Seeing as he is in Alburrta, I would go with fuel gelling. Warm up the filters and try to start again. If it runs for awhile, it is the paraffin in the cold fuel. You could just look in the tank, but hard to do on a motorhome.

saddlesore · 01-12-2022, 02:11 PM

Quote:

Originally Posted by bigb56

hmmm, I wonder if a critter could've nested in the exhaust?

LOL! I have had a squirrel set up house in an exhaust system... Was NOT a HAPPY Camper when I fired off that Cat.. and those acorns didn't fair very well either...

Cincy Steve · 01-12-2022, 02:55 PM

Cummins (US) warranty covers 5 years from in-service date or 100k miles, whichever comes first.

Unless the warranty in Canada is different, I would not have uncertified shops working on my rig.

bigb56 · 01-12-2022, 03:00 PM

Quote:

Originally Posted by saddlesore

LOL! I have had a squirrel set up house in an exhaust system... Was NOT a HAPPY Camper when I fired off that Cat.. and those acorns didn't fair very well either...

What's for dinner honey?

Roasted squirrel and smoked acorns!

Gdoubleoo · 01-12-2022, 07:35 PM

The mechanic with a quick inspection of all things , told me that the turbo would not spin . The Def system is also plugged. I instructed them not to touch it any further, It will go into Cummins Calgary shop tomorrow to be looked at around the 19th of January. Service manager told me I should have 2 years warranty on the engine, as long as nothing had been done that was not authorized by Cummins, before I purchased the unit (used) in October of 2021. I guess I'll wait and see. Not sure what would throw out the turbo like that? Thanks for all your help, this website sure has some great contributors.