I was going to post this before taking the truck in but didn't get to. I don't see any similar problems so I'll update but if anyone has an idea of what's going on let me know.
We have a 2017 F550 ambulance. It was just serviced with DOT inspection yesterday. Today, it went to a call and to the hospital with no issue. Fueled at the normal station that is more of a truck fuel stop and goes through a lot of diesel. Definitely fueled with diesel and not DEF or gas. On the way back pulling up a large grade it felt like it bogged down a second and then recovered. Just before it shifted out of higher RPM it sounded like there was a rattle from under the hood. It stops right after shift. DPF was at 75 percent at that point. About 10 minutes later and 8 miles it was at 90.
Left it outside and did a manual Regen. It rattled as the RPM went up but then sounded fine. No smoke, no soot and no diesel, oil or coolant leaking. It finished the Regen and we shut it down and checked under the hood. No signs of leaks or soot or any weird smells. Took it for a ride and Sure enough, after about 10 minutes it did the same thing and as soon as it did the DPF went from 10 percent to 30 percent while accelerating. It was then returned to the shop where it was at yesterday without any issues on the way except the DPF going to 50. That's where we are. Anybody have anything similar ever happen? 25,000 miles and it is serviced regularly.

 

bad fuel. check the fuel filters.

drain the separator and have a look.

 

I'd be pretty happy if that's all it was. That's not great, but it's certainly not the worse case scenario.

 

that is my take on it based upon what you have said.

Check those filters, use a cetane booster.

Watch out for the white cap from the bottle and dont let that in the tank.

Check for any codes?

 

No check engine light and I don't believe it popped any codes. It's been left at the shop for the night. I will definitely post what it comes back as or if it popped anything else they found on the scan tool.

 

I'm with Scott on this... If that truck had no problems prior to that last fill.up, check those filters for bad fuel...

 

If it’s filling up the dpf that fast my guess is sensors , injector, rocker arm side play , etc.


if the fuel had a lot of oil in it…it would fill up the dpf as fast as you are reporting.

 

So apparently after a couple of days at the shop the verdict is the DPF filter itself is bad and they are replacing the entire filter system. Fuel was ok... apparently with nothing to indicate damage to fuel system.
We try to make sure the filter gets cleaned down to zero using the regen request manually at the end of every month. For those in the know, is that not a good idea going forward? We use Peak Blue DEF from Napa in all 3 vehicles with the emissions system. This unit is heading toward 8 years old but I didn't anticipate the actual filter being the issue without finding another failure.

 

you are saying the DPF (diesel particulate filter) is bad..or the fuel system parts are bad?

What codes?

 

The diesel particulate filter was bad. Fuel system and fuel was fine according to what they told the other guys today. No other damage found. I didn't get to talk to the service guy this time around. Last I heard, no codes as of yesterday so I don't have much more to offer but I wanted to follow up with what they said.

 

DPF is bad then there would be codes with that such as P2002.

alot of money unless you have a warranty as it is around 3500 plus labor.

 

Not a mechanic but read a lot... I don't think there's nothing wrong with doing OCRs, operator commanded regens or manual regens...

Did they say what happened to the DPF? Was the substrate cracked? It sounds like you guys make sure the trucks finish regens.

Not alot of miles either... Does It idle a lot at all?