Need Help w/ an International Aftertreatment Issue

Hello all! I am having some trouble diagnosing an aftertreatment issue in my 2015 International ProStar with the Navistar N13 (MaxxForce) engine with DPF and SCR.

Some background: I purchased the truck in Tennessee last year (2021) in September with ~450k miles. I drove it home to California and took it to my shop just to get an overall idea of where it’s at mechanically. Shop said everything looked good, so I proceeded to drive without any major issues. The only issue I ever had was I started getting a check engine code for my aftertreatment injector/hydrocarbon doser - data valid but low. It was always a single occurrence, and I could clear the code and continue driving without issue. The code would come up every 1-3 days. In November, the truck derated and I limped into my nearest dealer. Turned out my thermal management assembly valve had failed. We replaced that and continued driving. Within a couple hundred miles of leaving the dealer, I already had the aft injector/doser code coming up again, always able to clear it and continue and never another derate.

I have kept up with regular maintenance and change the oil and filters every 5-8k miles. The only other issue that I have had is some decent oil consumption. I’ve noticed that within 5k miles after changing oil and filters, I lose around 3 gallons of oil. If I don’t change the oil and filters at that point, I continue losing about another gallon per 1k miles until I change it. This happens with both conventional and synthetic.

In the recent months, I’ve had my truck looked at by different mechanics all across the country. They all connect their computers and run forced regens. They have all come back saying that the sensors are reading properly and that my aft injector is working just fine. In terms of the oil consumption, I have been told that my truck has excessive blow by. However, I don’t have smoke coming out of my oil fill pipe.

So this brings me to my current issue. I now have 515k miles. On my last run, I went from Pennsylvania to California. About halfway through the run, I started losing power and my mpg’s dropped significantly (normally I get around 6.5 and I dropped to 4.7). Additionally, the truck was making me perform a parked regen at least once a day. The whole time, I was getting daily codes for the aft injector and for an incomplete regen (while driving).

When I got home, I took the truck to my regular shop. I had them replace the aft injector for peace of mind. They did, and within 50 miles of replacement the code for incomplete regen reappeared. My home shop is scratching their heads. Their theory is that either my ecm needs a software update from the dealer or that my DPF filter is cracked because all the data from the forced regens is reading perfectly within spec.

Another shop that I frequent in Texas has told me that they believe that all my aftertreatment issues are stemming upstream from the oil consumption. Due to the lack of blow by smoke in my oil fill tube, they believe that the oil is working it’s way into my exhaust either via a failing CCOS/jet plate, failing turbo, or a leak from an exhaust stem seal leading to oil in my exhaust manifold.

I don’t know where to start or what to do. Does anyone have any idea how I should go about fixing this issue? Any and all help would be so greatly appreciated!

For what it’s worth, I pull reefer all over the country usually around 40k lbs.

 

It’s definitely feeling like one! I had the filter pulled and baked by the dealer when the truck derated in November

 

I did have it checked out… many times, by many different techs. All said the injector was functioning properly. The derate was caused by a different component failure that did not throw a code until the stop engine light

 

Thank you! I called my local dealer this morning. They confirmed that my ECU is due for a recalibration. I’ll start with that