Exhaust smell and Hiss

[TonyDynamite]

Hey all,

Not new to Ram but new to Diesels. I just traded in my Ram 1500 Hemi for a 2500 Cummins and I noticed something interesting.

3 times now after driving on the freeway, I notice a heavy exhaust smell and a hiss when I come to a complete stop. The hiss isn't the brake system but I think something to do with the fuel. Once I tap the gas even slightly, the hiss goes away. But with the Hiss comes a heavy smell that I notice if my windows are down (which they are 90% of the time).

Now after a bit of street driving will go away, both sound and smell. But if I give heavy gas on the highway I notice it comes back. I immediately thought it was a exhaust leak, but if it was... it should be consistent and not coming and going.

I also think its important to note, that when traffic on the highway comes to a slow, and I am coasting at about 15 - 25 MPH I can hear and smell what I mentioned above if I had just recently gave it more than a quarter throttle. but again, if I touch the gas, his stops.

The truck "supposedly" just passed smog in CA according to the dealer fee I paid.

Wondering if anybody has insight on this. could it be something with the Turbo? Exhaust leak? Def System? or is it just normal

Thanks in advance!

 

[MegaRed]

What year? How many miles on it? Tuned? Deleted? Any other mods? A little more info will help the experts here.

 

[flan]

There is a gasket at the end of the downpipe also right after the DPF I would inspect those. Also check out your egr piping under the hood. Following that check the exhaust manifold and connection to turbocharger.

 

[Great White North Eh]

I could be wrong but it’s probably the sweet smell of DEF being fried by your exhaust. Mine used to stink but now it smells like Mr. Rudolph intend.

 

[TonyDynamite]

What year? How many miles on it? Tuned? Deleted? Any other mods? A little more info will help the experts here.

Sorry about that. Its a 2022, not tuned (yet), not deleted. Stock other than Airbags added

 

[TonyDynamite]

Sorry about that. Its a 2022, not tuned (yet), not deleted. Stock other than Airbags added

also 61000 miles

 

[TonyDynamite]

There is a gasket at the end of the downpipe also right after the DPF I would inspect those. Also check out your egr piping under the hood. Following that check the exhaust manifold and connection to turbocharger.

Thanks! Im going to check all those places today.

 

[TonyDynamite]

So update to all of this. Haven’t had time yet because of work to check everything. But today I got this warning on the truck. Has anybody seen this one before

 

[TonyDynamite]

So update to all of this. Haven’t had time yet because of work to check everything. But today I got this warning on the truck. Has anybody seen this one before

based on some research I am willing to bet what I have been smelling was the Active Regeneration happening on the truck and it never completed. I drove a extra 20 miles today passed my exit to try and have it do its thing... eventually just went home so I can go to bed. Fun times with my new truck!

 

[Units]

So update to all of this. Haven’t had time yet because of work to check everything. But today I got this warning on the truck. Has anybody seen this one before

That means your driving is not conductive to the exhaust getting hot enough for an active regeneration. I had that same message pop up on me a few times while site seeing on our trip last year to Yellowstone, 20mph and lots of stop and go, my truck didn’t appreciate that.

 

[56ram2500]

That means your driving is not conductive to the exhaust getting hot enough for an active regeneration. I had that same message pop up on me a few times while site seeing on our trip last year to Yellowstone, 20mph and lots of stop and go, my truck didn’t appreciate that.

Wow I just did Yellowstone and Mob arches, not once did I have problems from the low speeds in either park with Moab having the lowest speeds of the two parks.....

 

[werard]

Hey all,

Not new to Ram but new to Diesels. I just traded in my Ram 1500 Hemi for a 2500 Cummins and I noticed something interesting.

3 times now after driving on the freeway, I notice a heavy exhaust smell and a hiss when I come to a complete stop. The hiss isn't the brake system but I think something to do with the fuel. Once I tap the gas even slightly, the hiss goes away. But with the Hiss comes a heavy smell that I notice if my windows are down (which they are 90% of the time).

Now after a bit of street driving will go away, both sound and smell. But if I give heavy gas on the highway I notice it comes back. I immediately thought it was a exhaust leak, but if it was... it should be consistent and not coming and going.

I also think its important to note, that when traffic on the highway comes to a slow, and I am coasting at about 15 - 25 MPH I can hear and smell what I mentioned above if I had just recently gave it more than a quarter throttle. but again, if I touch the gas, his stops.

The truck "supposedly" just passed smog in CA according to the dealer fee I paid.

Wondering if anybody has insight on this. could it be something with the Turbo? Exhaust leak? Def System? or is it just normal

Thanks in advance!

Diesel "smog" in Cali is visual and OBD only no emissions testing.

 

[Units]

Wow I just did Yellowstone and Mob arches, not once did I have problems from the low speeds in either park with Moab having the lowest speeds of the two parks.....

I wouldn’t necessarily say I had a problem, truck just didn’t like all the slow driving and frequent stops while trying to preform an active regeneration, once we got on a semi long stretch of road it cleared out although it did take quite some time not traveling very fast.

 

[randthor]

I noticed the same thing on my 2500 right after hard pulls—turned out to be normal regen behavior. The hiss and smell usually happen during or right after a DPF regen cycle. It’s more noticeable with windows down. Still, I’d keep an eye out for any loose clamps or small leaks just in case.

Mini Militia App Lock​

 

[TonyDynamite]

I noticed the same thing on my 2500 right after hard pulls—turned out to be normal regen behavior. The hiss and smell usually happen during or right after a DPF regen cycle. It’s more noticeable with windows down. Still, I’d keep an eye out for any loose clamps or small leaks just in case.

Great to know! After a few trail and error I did find a clamp loose on the exhaust after seeing soot build up.

Getting a new clamp and gasket this week

Thanks for your reply!

 

[Brutal_HO]

That means your driving is not conductive to the exhaust getting hot enough for an active regeneration. I had that same message pop up on me a few times while site seeing on our trip last year to Yellowstone, 20mph and lots of stop and go, my truck didn’t appreciate that.

I don't know where to start. You're kinda twisting things up.

Passive regen = temps sufficient to keep the DPF soot free
Active regen;

Soot based active regen, generally due to driving conditions​

OR​

24 hour forced active regen​

​

Driving habits have little to do with a currently running active regen.

Active regen will force temps sufficient to perform regardless of driving conditions, working it can help improve regen time.​

Active regen does need time/temp to complete.​

 

[Brutal_HO]

Great to know! After a few trail and error I did find a clamp loose on the exhaust after seeing soot build up.

Getting a new clamp and gasket this week

Thanks for your reply!

22's can be problematic WRT excess regens so you might want to get setup to monitor and track them.

There was a TSB issued for a specific VIN range that were found to have defective DPF.

That said, if you're DD around town, you're going to see excess regens. Issues there are fuel usage and fuel in oil dilution. Up the OCI...