DD15. Doc face pluging

Injector(s) over fueling are the most frequent cause of doc face plugging on DD13/15 equipped trucks. There are tests in DDDL to test for this issue. Don't know how you checked injector performance.

 

What is DL and ISB?

 

You will need to post those codes here.

 

We see it in our trucks that haul a lot of short 5 mile hauls. The trucks just get spooled up enough to start dowsing for a regen, just before the truck stops to unload. So we get a spray of diesel on the DOC face just before the truck is idled for 30 minutes to unload. Letting all the spot stick to the fresh diesel. We found that at least once or twice a day the trucks need to get out on a 15-30 mile stretch of highway to let it do it’s passive regen.

Other than that, a dribbling doser injector can cause a buildup of soot.

 

The doser injector (7th Injector) starts spraying diesel into the exhaust stream when it MCM decides the environment is right for a passive regen. That diesel when pushed through the DOC is burned and is what generates the heat needed for burn down the carbon in the DPF’s. If the passive regen is interrupted before diesel can be burned off (temps above 500deg) then it leaves a wet surface to collect carbon soot on the DOC, instead of getting it stored in the DPF’s to be burned during a regen.

 

The DOC face cleaning is a neat Idea Detroit came up with but it’s not 100% effective. You may have to get ahead of it by changing driving habits. If that doesn’t fix it, then you’ll need to manually clean them by pulling the DPF’s out, attaching a really good Vacum to the inlet where the exhaust pipe comes in. And blowing out every tiny block in the DOC’s with the strongest pinpoint of shop air you can devise.