Cummins rough idle on startup

[flan]

It sounds like to me the vanes on the turbo close for the first few min to assist with the warmup process, it’s noisy by the front of the truck, sounds like it’s bogging, but that goes away after a determined engine temp has been reached.

 

[Burn'n Oil]

It sounds like to me the vanes on the turbo close for the first few min to assist with the warmup process, it’s noisy by the front of the truck, sounds like it’s bogging, but that goes away after a determined engine temp has been reached.

Indeed they will. Additionally, the EB will activate to assist in engine warm up. When it's cold out and the CTD is left to idle, it's quite apparent when the EB turns off and the VGT returns to normal scheduling - the Cummins will instantly get very quiet.

 

[BamaStar]

I've noticed the high idle kicking in down here in the south (Alabama) on cold (for us) mornings in the 20s and 30s (F). It scares my dogs and they wont go near the truck. They never were scared of the HEMI! . I filed my DEF tank with a box (Peak) and it took a whole box, then when using a second box, a little went in then it began overflowing. I was hoping not much got in the uncovered diesel fuel filler tube. I have driven about 500 miles since and my needle has moved slightly off full. I was thinking it would take longer since there is supposed to be a reserve above full. Still learning all this. I'm also getting about 17-18 MPG combined city/highway driving.

 

[Burn'n Oil]

I've noticed the high idle kicking in down here in the south (Alabama) on cold (for us) mornings in the 20s and 30s (F). It scares my dogs and they wont go near the truck. They never were scared of the HEMI! . I filed my DEF tank with a box (Peak) and it took a whole box, then when using a second box, a little went in then it began overflowing. I was hoping not much got in the uncovered diesel fuel filler tube. I have driven about 500 miles since and my needle has moved slightly off full. I was thinking it would take longer since there is supposed to be a reserve above full. Still learning all this. I'm also getting about 17-18 MPG combined city/highway driving.

 

[BamaStar]

I have used 1/8 tank DEF with about 700 miles of driving. Is this normal?

 

[Deleted member 80]

I have used 1/8 tank DEF with about 700 miles of driving. Is this normal?

I am at a bit over 12K miles. Overall, approx 12% towing, and mine has average about 800 mpg on DEF. While towing, I would estimate about 500 mpg on DEF.

 

[Brutal_HO]

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.

Good info.

I came here looking for info on the rough idle I'm experiencing in my brand new truck and it sounds like it's normal.

FWIW, I live at 5900' elevation.

Truck has dual alternators.

 

[thestuarts]

Good info.

I came here looking for info on the rough idle I'm experiencing in my brand new truck and it sounds like it's normal.

FWIW, I live at 5900' elevation.

Truck has dual alternators.

My 2019 HO started idling really rough after the dealer updated the PCM from version 52401932AF to version 52401932AG. The PCM update was done in February to fix excessive DEF usage per TSB 18-052-19.

Yesterday, the dealer updated the PCM from version 52401932AG to version 52401932AH for recall VB6. The truck idles normally again.

If your PCM is version 52401932AG, consider updating to version 52401932AH.

 

[MSundet]

My 2019 HO started idling really rough after the dealer updated the PCM from version 52401932AF to version 52401932AG. The PCM update was done in February to fix excessive DEF usage per TSB 18-052-19.

Yesterday, the dealer updated the PCM from version 52401932AG to version 52401932AH for recall VB6. The truck idles normally again.

If your PCM is version 52401932AG, consider updating to version 52401932AH.

Sent from my iPhone using Tapatalk

 

[Wrayzor]

I recently moved to a higher elevation (Albuquerque, NM) and my truck just started doing this stumble upon starting thing; Glad I read up on the info and hope it's not my CP4 going out. Runs fine once it gets going with no issues.

 

[SMK Shoe]

Have this same problem. Start up first thing in morning and shakes and rattles till high idle kicks in. Noticed the volts bounce all over the place for a couple minutes. Once its warmed up purrs like a kitten. I really notice it on cold mornings because Im laying in my sleeping bag waiting for the cab to warm up to start my day.