Cummins rough idle on startup

[jared43758]

And a second video that’s louder

 

[elephantrider]

are you in a higher elevation area by chance ? mine was doing that when in colorado over the last
two wks, and had some noticeable surging when holding speed up hill. got back to central texas
and both issues went away.

 

[Deleted member 80]

My buddy has a '19 3500 HO, and also has rough idle, stumbling, and even stalling when at high elevation.

 

[elephantrider]

lol, same here. best friend has a 19 that does all that as well.

i can't imagine anyone living 6k ft higher elevation having to deal
with that all the time. i'd say maybe it was a learning process, but
i was up there almost two weeks over the holiday and it never got
better.

 

[Deleted member 80]

Just another problem waiting for a reflash

These trucks were rolled out so late in the model year, yet still have a lot of half-baked stuff.

 

[jared43758]

I live in Ohio and haven’t been traveling it started this only recently

 

[jared43758]

What do you mean by this?
Also this is not a first off the line truck. I ordered 9/16/2019. It was build by end of September
UOTE="1HasBeen, post: 13014, member: 80"]
Just another problem waiting for a reflash

These trucks were rolled out so late in the model year, yet still have a lot of half-baked stuff.
[/QUOTE]

 

[elephantrider]

some folks subscribe to the theory that fca pushed these trucks out without a robust ecu tune, so the
dealers flash updates almost anytime your truck is there.

 

[Deleted member 80]

What do you mean by this?
Also this is not a first off the line truck. I ordered 9/16/2019. It was build by end of September
UOTE="1HasBeen, post: 13014, member: 80"]
Just another problem waiting for a reflash

These trucks were rolled out so late in the model year, yet still have a lot of half-baked stuff.

[/QUOTE]
What I mean is they rolled out the 2019 Ram HDs so late in the model year that the other two were already showing their 2020s. You would think they would be more buttoned down than they are. My 12" U Connect is bug ridden and waiting for a reflash that never comes. My Aisin has been reflashed twice and still slams from 2-1. My buddy has the rough idle, stumbling at elevation with no resolution in sight.

 

[jared43758]

So by flash you just mean apply most recent updates to ecm that current trucks being made are being used, likes fixes or improvements, like iPhone updates?
QUOTE="elephantrider, post: 13031, member: 781"]
some folks subscribe to the theory that fca pushed these trucks out without a robust ecu tune, so the
dealers flash updates almost anytime your truck is there.
[/QUOTE]

 

[elephantrider]

^ correct!

 

[Deleted member 80]

So by flash you just mean apply most recent updates to ecm that current trucks being made are being used, likes fixes or improvements, like iPhone updates?
QUOTE="elephantrider, post: 13031, member: 781"]
some folks subscribe to the theory that fca pushed these trucks out without a robust ecu tune, so the
dealers flash updates almost anytime your truck is there.

[/QUOTE]
Yes, that's what I am saying. Except they either have not come, such as the bug-riddled 12" Etch-A-Sketch, or they have been ineffective, such as my Aisin that SLAMS from 2-1 at slow speeds.

 

[jared43758]

I myself haven’t had any shift problems with my aisin. It does seem to downshift funny sometimes when I’m driving on hilly roads with the auto exhaust brake on. Don’t really like it. I usually don’t leave exhaust brake on and only tap it on when it’s useful on bigger hills and then right back off again when I’m at the bottom

 

[jared43758]

Ended up just updating my truck. The things they highlighted didn’t really cover my issue but seems to fix the issue for now. Although now when I’m stopped at a light in gear it feels like it doesn’t idle as smooth.

 

[jared43758]

 

[Deleted member 80]

Good info. I will pass this along to my buddy with the stumbling 3500.

 

[Dialed-In]

Have noticed a bit of rough idle lately. Also it kinda coughs or stumbles on cold start warm up. HO 2019.

 

[jared43758]

After I had my update my truck now says upon startup “cabin warm up in progress” on the dash. But it’ll start and run smooth for a couple seconds and when that message kicks on it will run pretty ruff until the high idle kicks in which it doesn’t always and I’m not sure why on that. Idk if the cabin heater electric drags the motor down so much it makes it run rough, I wouldn’t think, or something which the egr process chokin the motor to get the engine to warm faster. I’m going to stop in a couple weeks to get my trans updated and will check then to see if they have a update fix for the engine idle

 

[crzysnake137]

Does this apply to the 2500? Have had some rough idles and rough running when cold. Also excessive def usage

 

[Burn'n Oil]

After I had my update my truck now says upon startup “cabin warm up in progress” on the dash. But it’ll start and run smooth for a couple seconds and when that message kicks on it will run pretty ruff until the high idle kicks in which it doesn’t always and I’m not sure why on that. Idk if the cabin heater electric drags the motor down so much it makes it run rough, I wouldn’t think, or something which the egr process chokin the motor to get the engine to warm faster. I’m going to stop in a couple weeks to get my trans updated and will check then to see if they have a update fix for the engine idle

The EVIC msg you have post update has to be associated with the supplemental cabin heaters - there's three of em. The rough running/chugging is, anecdotally, normal for these engines during the first couple or three minutes of operation when the OAT gets close to freezing, especially if the truck has a single alternator. Consider that the grid heater is drawing upwards of 200A when it cycles on. Then there's those supplemental cabin heaters trying to work too. And, if it's cold enough, the fuel filter heaters and DEF line heater will be asking for juice. And all that doesn't include the cabin demands for power (HVAC blower, heated seats/steering wheel, radio etc). Watch the volt meter after a cold start. The voltage will swing back and forth from the low 11s to mid 13s as the grid heater cycles. The rough running/chugging is simply the engine's attempt to maintain idle speed while the batteries are being pounded by the massive elect load.

Auto activation of high idle is dependant on OAT and coolant temp. It the engine is started at OATs of about 20F or below and without the benefit of a block heater, the idle will increase to 1000 RPM shortly after startup. If the block heater has been plugged in for a few hrs, the engine will initially idle at about 650 RPM and increase to high idle after about two minutes. With an OAT of about 20F or higher and with no block heater assist, the engine will initially idle at 650 for the first two minutes. Below 0F, and regardless of coolant temp, the engine will always idle at 650 for the first two min of operation.