How often should a forced regen be done?

The truck will regen based on it's own demands. Things like short trips and higher soot output from engine will require more frequent regens. Also you'll find that when you start needing forced regens(even with just age), they'll become more frequent due to higher ash loads in the DPF. This eventually will need to be serviced and cleaned.

 

Went through something similar.. Ended up getting the DPF and Dox? Cleaned at a Peterbilt dealer and everything went back to normal. I idle a lot so for me I should get my DPF cleaned periodically..maybe every 200k.

Another thing I do is when it gives me a passive regen every 4 hours of idling I hit the manual regen switch. Sometimes it will put it in a full 45? minute regen..most times not. I only hit the switch if I got time to wait until it completes.

 

Certain engine faults can inhibit passive regeneration from occurring. Fix your check engine light and then see if the regen request is still occurring too frequently.

 

Much like goodsnap stated, your truck should be doing passive regens anyways. Another reason on top of codes it won't successfully do this is low DOC temps. This can be caused by a plugged DOC, exhaust leak, etc... Get your nox sensor issue diaged and fixed first.

 

I’d say, you’re going to continue with intermittent CEL’s, until you get the DPF cartridge cleaned (MX13 interval is 220K-250K, IIRC). If you own the truck, get the cartridge out, take it to a car wash, soak it in Gunk engine degreaser (not the foam crap, the regular stuff), then, thoroughly wash it, blasting every passageway clear. If you can’t get it completely clean, a new cartridge is ~$3K, IIRC. In addition, I’d replace the DPF sensor assembly (~$200, online). You’ve already replaced the NOX sensor, so it should be good. The DPF maintenance should get it running clean.

Everybody has their opinions on additives. However, Hot Shots EDT seems to be one of the known effective additives. I’ve seen an experiment where a fleet owner dosed the fuel and left the truck idle for 8 days. Data showed the truck didn’t perform a single regen. I know a guy who sells their stuff through his diesel repair business. My buddy runs their winter treatment. YMMV.