LML Hypothetically speaking.....

[username taken]

Say the honeycomb was removed from the scr/dpf canister on an LML Duramax. No tuning or other changes. DOC would stay in place to burn any additional fuel. Hoses, sensors etc all hooked up.

My thinking is that there would never be enough back pressure to trigger a regen, and the truck would "regen" only as often as the minimum coded in to the computer - like once every other tank of fuel or every 700-800 miles or something, as opposed to every 100-150 miles like it does around town. It would still inject some extra fuel into the DOC and superheat the exhaust and everything, just much less frequently and for a shorter duration.

Not sure what would happen with the SCR - guessing it would just blow the unused urea out the exhaust since the SCR honeycomb In the front part of the DPF housing would be gone too.

I'm sure I'm not the first person to think of this. Anybody out there could tell me if it would work and why or why not? Any brave souls actually tried it?


Sent from my iPad using Tapatalk

 

[Burn Down]

Not sure on the d-max but Caterpillar is reading the back pressure and pressure difference between the inlet and outlet of the DPF, if it is not in it's specified pressure range, codes are set and limp modes are on the way. I would be willing to bet GM is doing the same.

 

[Blackmax123]

The bigger cummins engines work the same way. So I'd also bet a duramax would do the same..

Sent from my SM-G935V using Tapatalk

 

[TheBac]

Moved to LML section of Hard Parts......hypothetically speaking.....


PS, they used to call it "gutting the cat" back in the day. Highly doubtful it would work nowadays with all the sensors and computers keeping track of everything in modern vehicles.

 

[chevor]

Probably trigger CEL and automatically trigger regen. Like LMM and MAF sensor fault.

 

[NC-smokinlmm]

Pressure differential will trigger cel. No way around it, it knows how many regens for fuel burned, if algorithm gets off cel is set and limp will follow.

 

[blackLTZ]

Like stated before would trigger a dpf deferential pressure sensor fault, the. Talking about the scr you will get scr efficiency faults since it uses both of the box sensors to calculate efficiency on aftertreatment and since the dpf and scr did not do their job or dropping 90% of ppms deratr would occur eventually, so. Best way around it delete it.

 

[Texasz]

Be a good way to fool visual emission states though, gut it and tune for delete, no need for exhaust.... just spitballin. lol.

 

[Alisobob]

My thinking is that there would never be enough back pressure to trigger a regen, and the truck would "regen" only as often as the minimum coded in to the computer - like once every other tank of fuel or every 700-800 miles or something, as opposed to every 100-150 miles like it does around town. It would still inject some extra fuel into the DOC and superheat the exhaust and everything, just much less frequently and for a shorter duration.

I left the pressure sensor plugged into the wiring harness, but disconnected the two pressure sensing hoses, and taped them shut.

I now get 700 miles between regens, as you described. It also stopped the annoying quick soot count up to 15 grams or so after a regen

The funny thing is its been months since I've done this, and not one CEL or code.

I had the CEL go on last week, but it was for a failed #6 glow plug. When checking the glow plug code, I could see stored codes for the lack of exhaust backpressure, but they never triggered the light or "limp home" mode.

This in on a 2011 LML