Aftertreatment problems got me down again/SPN 4364 FMI 31 code

Probably not completing regen if it is doing that. Have you had it monitored during regen?

 

Oh no. Too bad there isn't a once and for all solution to emissions issues. Guess you can just put the truck down for 6 months while they try to fix it with parts they can't get!

 

If I thought the excessive smoke and NOx codes were related, I'd probably test for boost leaks. At the very least, try to solve the smoke issue first, then tackle the NOx conversion problem. If you haven't touched the EGR system, it would be a good idea to pull the cooler off and have it cleaned. You should be able to test the EGR valve by disconnecting the electrical connection, then put a rubber glove over the pipe downstream. If the glove inflates when you start the truck, then it means the valve is allowing exhaust gases to bypass the valve. Check the exhaust system for any evidence of leaks, like soot around the connections. With the Volvo motor, the truck uses the turbo to help it warm up, so I can spray the connections with soapy water and look for bubbles if the truck isn't warmed up yet. I'm not sure if Cummins warms up the same way. A smoke machine would work even better. Injectors or turbo could also be an issue. I would think you'd notice strange noises, poor fuel economy, or codes for DPF regen too frequent.

NOx conversion codes can be tricky. Start by checking the DEF quality. Refractometers should be pretty cheap, I think like $20 on Amazon. If the quality is good, make sure the doser isn't blocked up. You can clean it up with distilled water and a toothbrush. If it's really crusty, you can use a plastic dental pick or something. If you just wanted to replace the doser, it's like $300. Someone with the software can usually run a test to make sure it's injecting the amount it's supposed to. They should be able to monitor the inlet and outlet NOx sensors to give an idea of if they're reading accurately. If everything checks out at this point, it starts to get expensive. The DOC is around $2k, and the SCR is probably around $6k. I think if the DOC catalyst is going bad, your regens will have a low temperature since that is what causes the fuel from the 7th injector to heat up in the filter. You could try cleaning the DOC instead of replacing it. DPF Alternatives can do the DOC and DPF for a few hundred dollars. New clamps and gaskets are a good idea, but they can get expensive.

The only truck I work on is my own, so these are just ideas of where I would go with it if it were me. The emissions system is almost entirely bolt on, so it can be done with basic tools. If you're having a shop remove components to be cleaned, it's a lot more expensive than doing it yourself. Rawze is a pretty good resource for emissions issues on the ISX. I also carry an OTR Performance reset tool so I can force my own regens if I get derated. NOx codes are a pain in the ### with this tool, since you have to run a full regen after clearing the codes, and if you didn't fix it, it will derate again in like 300 miles. One way I get around this is to carry a bad NOx sensor, which throws a code every 3 driving cycles or 150ish miles. But I can just plug the tool in once and it clears the code with no derate. I'm not sure how their new tool with the subscription is. I'm not sure if you get everything you need at $600 per year, or how that compares to Cummins Insite. The down side to subscriptions is that if you don't have emissions problems every year, you're wasting your money.

 

I own the OTR tool as well . It really will save you some money and time . Sometimes the code thrown is as they call it a ghost code or a hitch in the system that can be reset by clearing and doing a forced regen . Also it will save you a huge tow bill .

 

See you again in 3 months