ecm completed regens

[JimT]

Sorry for the lag in response...

Based on your reply and my own first hand knowledge I'd say you need a new DOC and probably a new DPF. I had nearly the same issue. While a soot reduction by disabling the EGR might point to a faulty EGR valve, it's unlikely to be the main problem with incomplete regens.

The blue/white smoke and heavy fuel smell points to a lack of proper oxidation at the DOC. If it's occasional it might be related to exhaust leaks (especially common from a damaged exhaust bellows just after the turbo), EGR valve malfunction and DPF injector clogging/dripping (carbon buildup around the injector, bad or leaking injector, failed "dpf purge air actuator" which doesn't properly clear fuel from the lines allowing excess to potentially drain out through the injector into the exhaust). But if the problem persists then the DOC itself is just plain worn out.

Unfortunately when the fuel passing through the DOC doesn't oxidize and burn properly then it coats the DPF in addition to any ash or soot. This leads to greater exhaust restriction and the need for more frequent and increasingly less effective regens. Active regens typically fail, spew lots of blue/white smoke, cause temp alarms at the SCR can. Parked regens will usually work, but sometimes last much longer. Eventually the increased use of parked regens will wear out the DOC to the point that even those will fail.

I had these exact symptoms develop over the course of a year and a half and found myself at the point of impending doom almost exactly 11 months ago...