2019 Cummins Rough & Tumble Idle After Morning Start Up. What could be wrong?

[Docwagon1776]

Let me see if I got this right, your saying that fuel filter media does not deteriorate or that the media is not affected at all after sitting in diesel for 2 years?

Simply sitting in diesel won't cause it to deteriorate any meaningful amount. Diesel is nearly neutral, much less acidic than gasoline.

Different question than how long it will last catching contaminants and being subjected to the level of hydraulic pressure of the fuel system before flow rate is compromised, though.

Diesel contains tiny waxy particles that eventually plug the pores of the filter even if the diesel itself is never contaminated. How long that takes, I'm not remotely qualified to answer. Much like oil changes, I'll go with the maintenance schedule the manual lays out.

 

[BossHogg]

33,000 miles on it.

I start it and then bump the idle up to 1,100 and for several seconds it's a Rough & Tumble, truck shaking phenomena

And the DPF was just cleared after yesterday's high RPM 220 mile round trip to Phoenix.

It never did this before.

What could be wrong?

How long after start-up does it take for the rough running to stop?
What is the ambient temperature when first starting the engine?
Does this happen on every start-up or just sometimes?
Do you buy your fuel from the same station?
Have you scanned for codes during the event?

Did you make any changes to the truck, add anything, have software updated, or was the truck in for a dealer visit before you started seeing this issue?

 

[Gr8bawana]

I just bought the two Mopar filters on eBay for $33 with free shipping

The latest cost for the dealership to change the filters is 329.95 plus tax --so, they want over $300 for labor

I think I will YouTube how to change them myself. My extended warranty runs out in Jan, so I don't care if they don't have a record for that service.

Well there you go.

 

[Gr8bawana]

My truck started doing the same thing when we were camping last month and the morning temps were in the low 40's. Low enough that the grid heater was activating.
One morning I noticed the truck chugged for a few seconds after start-up. The next morning I realized I hadn't heard the normal sound of the grid heater relay activating then turning off.
It did the same thing for the rest of our trip with no ill-effects.
I suppose I really don't need it since it never gets anywhere near 0° where we live.

 

[nlambert182]

My truck lopes in the morning if it's below 70 degrees outside, but mine has to do with the tune (even though it's stock HP). Idles/drives perfectly normal once it warms up.

Some suggest Baldwin for filters but from my experience with them on bigger engines I don't touch them. Coke can with some paper towels shoved in them. We've seen more than a handful collapse. I can't speak to longevity sitting around because I DD mine. I do 2 filter replacements per year. Typically once in the early spring and once again in late fall.

 

[dordoc2506]

They are both Mopar filters, Mr Lambert.

I purchase mine direct from Cummins, they sell the right parts at half the price as dodge dealers....

 

[Gr8bawana]

I purchase mine direct from Cummins, they sell the right parts at half the price as dodge dealers....

Hmm...half price really? They wouldn't happen to be direct from cummins on amazon would they?

 

[nlambert182]

I purchase mine direct from Cummins, they sell the right parts at half the price as dodge dealers....

Wow, you must get some really large discounts.

 

[truck2014]

My truck lopes in the morning if it's below 70 degrees outside, but mine has to do with the tune (even though it's stock HP). Idles/drives perfectly normal once it warms up.

Some suggest Baldwin for filters but from my experience with them on bigger engines I don't touch them. Coke can with some paper towels shoved in them. We've seen more than a handful collapse. I can't speak to longevity sitting around because I DD mine. I do 2 filter replacements per year. Typically once in the early spring and once again in late fall.

You are changing those fuel filters on your 6.7 diesel every six months or so , is that because of mileage or whatever ? I do mine every April , mileage is never a factor , I only put 5-7k per year on them .

For that matter , I do all the filters @ 1 year , oil , air ,and fuel . Have done since off warranty on my 2014 , so thats been for nearly 9 years now .

 

[nlambert182]

Yep, usually mileage. I don't go by time. It isn't really a factor quite frankly. Doc said it earlier, but diesel isn't going to deteriorate the filters.

 

[06 Dodge]

You are changing those fuel filters on your 6.7 diesel every six months or so , is that because of mileage or whatever ? I do mine every April , mileage is never a factor , I only put 5-7k per year on them .

For that matter , I do all the filters @ 1 year , oil , air ,and fuel . Have done since off warranty on my 2014 , so thats been for nearly 9 years now .

I change oil, oil filter & rear fuel filter every year or 15K, front fuel filter every two years or 20K, air filter inspect every year replace every 3 years or 30K

 

[Gr8bawana]

I purchase mine direct from Cummins, they sell the right parts at half the price as dodge dealers....

Well? Aren't you going to tell us where you get these 1/2 price genuine Cummins filters?

 

[Docwagon1776]

Wow, you must get some really large discounts.

I don't know about that poster's situation or this particular filter, but if you can qualify for fleet pricing you'd be surprised how many things are suddenly half off or better direct from OEM. It's pretty comparable to wholesale. OEMs *generally* won't compete with their retailers by offering lower direct prices to retail consumers, but like everything there are exceptions.

NAPA is the same, or at least it used to be, even at the store. I have no idea what the qualifications are these days, but sometimes it's as easy as having a business credit card and a sympathetic sales manager. When I still had a Ford diesel I had fleet pricing due to my affiliation with the city fleet and it was a huge difference.

 

[nlambert182]

We had a tiered pricing model at the dealership I worked for. Level 1 was a walk-in (highest price), 2 was your average small business owner (1-2 trucks) that would get general maintenance done on site, 3 was someone with a fleet who did all their own work, and 4 was a fleet where we did all of their work.

The difference was about 40% from a Level 1 to a 4. We were the Cummins dealer, but on average we were similarly priced to other 3rd party resellers that sold genuine OEM. We were rarely much higher.

 

[Goose55]

34,000 miles on a 2019 6.7L H.O.

I thought it might be the DPF, but others here said it could be fuel filters. since it is slightly overdue.

I'm going to have them replaced on Tuesday. Now, if that rough start up is still there, than what?

 

[06 Dodge]

34,000 miles on a 2019 6.7L H.O.

I thought it might be the DPF, but others here said it could be fuel filters. since it is slightly overdue.

I'm going to have them replaced on Tuesday. Now, if that rough start up is still there, than what?

Does AZ require bio to be mixed in with your diesel? If so that could be one problem if it gets at or below 36 degrees overnight, also Bio diesel has been known to allow algae to grow an that can cause filtering problems....

 

[crash68]

how much fuel has been ran through the truck since it been starting rough?
If you burned through two or three tanks worths, then I would write it off as possible bad fuel.
That low mileage for a '19 Cummins, you might want to try running some Diesel Kleen +Cetane Boost see if that helps along with work the engine good too

 

[Goose55]

how much fuel has been ran through the truck since it been starting rough?
If you burned through two or three tanks worths, then I would write it off as possible bad fuel.
That low mileage for a '19 Cummins, you might want to try running some Diesel Kleen +Cetane Boost see if that helps along with work the engine good too

Thank you !

It's been having rough starts for many months, so I'd say 3 or 4 full 32 gallon tanks of fuel.

I have used a couple large bottles of Diesel Kleen +Cetane Boost and the engine gets worked very well on the long trips to Phoenix

 

[nlambert182]

Is the truck towing on those miles to Phoenix, or cruising empty? That does matter in terms of being "worked very well". An empty trip is not the same as towing. Towing is where this engine likes to live.

 

[Goose55]

Is the truck towing on those miles to Phoenix, or cruising empty? That does matter in terms of being "worked very well". An empty trip is not the same as towing. Towing is where this engine likes to live.

It's empty

So, it could be the DPF after all?

Last trip it did a passive regen