Mine was at about 800 miles. I was backing into driveway and smoke was coming out from under hood, don't remember if at high idle. I don't think it has happened again.

 

I guess the issue is that you'll never even notice if you went into regen going down the freeway.

-TJ

 

Correct, it will also regen faster with the higher speeds.
The smoking is an issue with the exhaust pipe not seated correctly from the factory.

 

what is this regen you 2 are talking about?!?! sry for newb ? just trying to learn!

 

Read up here: http://www.duramaxforum.com/forum/07-5-2010-lmm-duramax-powertrain/74721-dpf-info-thread.html

 

I did not know what smoke was so I shut truck off. At next start we were driving at about 40 - 45 mph and I did detect a smell in truck like something was hot, but only lasted for a few minutes. I guess that was from regen finishing cycle.

 

Probably, the smell will go away the more it regens as the stuff from production burns off

 

had mine fixed at the dealer no more smoking. You can still smell a slight burning but its alot better.

 

Now that I have ~1500 miles on my truck I think maybe the smoke I had on my first regen could have just been manufacturing oil etc. burning off everything the first time it got that hot. I've obviously had regens since and never noticed anything. Now, I could have been rolling every time so I'm not 100% sure yet, but I do know I haven't seen/smelled smoke since.

-TJ

 

I'm at 12,000 right now and its only happened 2 times. Is this bad?

 

How are you determining when your truck regens? It probably happened many times during freeway driving that you never noticed.

-TJ

 

It will do it once per tank of fuel. Mostly depending on your driving conditions. Im on the freeway all the time and mines going into regen almost every tank of fuel. My fuel economy sucks for about 30 miles. I reset my MPG icon when I get onto the freeway. If you keep doing that you will notice the MPG drop and that means you are going into regen. Other then that if your on the freeway you almost dont even know its happening

 

How much of a drop?



What have you seen in terms of the MPG drop when you have gone into regen?

 

1000 miles

I am at around 1000 miles on my LML, I have no idea if it has gone into the Regen mode, certainly no smoke or smell. 80% has been freeway so I probably wouldn't have noticed it at freeway speeds.

 

I am at around 1000 miles on my LML, I have no idea if it has gone into the Regen mode, certainly no smoke or smell. 80% has been freeway so I probably wouldn't have noticed it at freeway speeds.

Design intent is that you do not notice regen..

 

I have about 7300 miles on mine. The tech at the dealership said it has regened 14 times and it takes at least 45 min to complete a regen cycle. I cannot stand this thing. I do all sorts of driving. Some weeks it's alot of short trips under 20 minutes. It never gets a chance to finish the cycle. I have had it put me in limp mode which is complete BS. I drove for an hour in limp mode on the freeway trying to get it out of the cycle and it would not. I think they should tell you about this process before you buy these things. I drive 15 miles to work every day. If it goes into regen at that time why in the hell would I continue driving just as i get to work or home? Frankly I cannot believe that eveyone isnt more upset about this. Doesnt it defeat the purpose of this whole emmisions thing by having to drive more and use more fuel to do the regen? Let alone the extra cost, waste etc. Now we have DEF with even more waste. Some place has to make it, deliver it, dispose of the containers etc. all for what?
I feel better now.....

 

Doesnt it defeat the purpose of this whole emmisions thing by having to drive more and use more fuel to do the regen? .

of course it does..

welcome to how governments operate.

 

so I wrote a letter to GM-Powertrain and also Chevrolet as well as went thru their Patent and Suggestion website and requested they create a minor software update that will program the Re-Circ vent in the cabin to activate whenever the regen cycle is going. This way, the smoke from the louvers will not re-enter the cabin. They told me that they thought it was a brilliant idea and have escalated it up the food chain to get a service order done.. Hope we see this soon.. it's a bit odd having that smoke, but even more odd having it come thru the cabin since I generally see this occur at idle in traffic!

 

Limp mode was not due to the DEF. Perhaps something else caused it but the tech i talked to said if you do not allow the regen cycle to happen 3 times it will force you into limp mode.

 

wow, I wonder if he's right? Seems like it would be near impossible to stop it form happening however... all the truck needs to be doing is running (even at idle) for it to occur... I can't see how that can be blocked 3 times in a row... This is worth checkin on, but I wonder if this tech wasn't confusing issues and you might have a different issue going on entirely.

 

I go in depressed mode when regen happens, see'ing around town mpg go from 17, to 10ish! One question, if I leave truck idling does regen still go through its process, or does it have to be driving for min of 30 miles? Because I drove a decent 25 miles, and it was still happening, idle went up to 800, and as I came home I left truck idling thinking it will still clear; took it another 6 miles and it was still getting poor mpg. But, truck is a damn beast.

 

I think you need to drive it at speed a while to get a good regen. The idle regen doesn't work as well essentially. I too have found this a bit frustrating but still worth it to own this machine.

 

The truck does not regen at idle :

Notice: Extended idle should be
avoided because the DPF system
is not capable of self cleaning
at idle. During extended idle
operation, monitor the instrument
panel telltale lights and Driver
Information Center for messages
and take appropriate indicated
action. Continued idling with the
warning light/message on could
cause irreversible damage to the
DPF requiring repair and possible
replacement that might not be
covered by the vehicle warranty.
You will also notice a change in
the exhaust sound and engine idle
speed. This is normal. See Vehicle
Messages on page 5‑10.
If you continue to drive with the
DPF warning message on and the
exhaust filter is not cleaned as
required, the Malfunction Indicator
Lamp and the ENGINE POWER IS
REDUCED message will come on
and dealer service is necessary.
See Malfunction Indicator Lamp on
page 5‑6 and Engine Power
Messages on page 5‑11.

 

I wonder if that's true for both LML and LMM? The reason I ask is...

A) why the elevated idle?

B) why the smoke from the downpipe issue if that 9th injector isn't active at idle?

Are we sure we are talking apples to apples here? Or does the LML regen at idle?

 

I was under the impression the elevated idle was to 'keep the exhaust warm' in anticipation of resuming the regen cycle., but I don't know this for sure.

 

I now have 5,300 miles on my 2011. To the best of my knowledge I have never witnesses a regen, haven't smelled any of the symptoms, mileage maybe up or down, but no other indication of hot smells, high idle, etc. Dealer told me I might never know of a regen cycle unless I attempt to shut down while it is actually in progress. About 2,000 of those
miles were towing approx 12,000 lbs.

 

Just as intended in the design....as the manual says 'automatically with limited operator involvement or awareness'

 

What is the typical frequency for a regen to happen? I seem to have it happen as often as every 200 miles of basic driving, mostly on freeway. Seems too often but ???

I dont get fumes, smoke or smell but I do see the EGTs go up on my #2 EGT sensor (Bullydog monitor BTW)

Is there a way to control or limit the regen process?

 

LMM's regen about every 400 miles
LML's regen about every 700 miles

There are vender products which can 'change' this, but might cause issues with emissions inspections.

If your LML is regening every 200 mile something is probably wrong with it.

 

no way to control or limit it... I to get it often, but that's cause I'm driving around town a lot.

 

I have had regens every 900km(+or - 20km), very consistant so far.

 

just popped my regen cherry at 480 miles. This is the first and 50% my miles were highway and 50% city. This is my first diesel and it is the best truck I have ever bought and probably ever will buy.:rockin

 

They should have a timer on it incase you wanna shut it off. Almost like a turbo timer, if you park and it's half way done you should be able to shut it off and walk away and the truck will run until completed then shut off. I think that'd be a pretty good idea if any gm reps are reading this.

 

Mxpop- what bully dog are you using? I'm running the G/T it monitors soot level and will let me manual regen at any time. It has come in handy a couple of times and I will be using it before plowing. I'm assuming you have a LML. If you are running a tune and you're heavy on the throttle a lot you probably would regen more often. FWIW

 

i have a 2012 lml denali dually, i have 1300km and i believe have been through 2 possibly 3 regens. I havent had a chance to scroll through the whole manual yet as i am at work now on shift, but is their an "instant ecomonoy" litres per/100km or is their just an average litres/per 100km on these new trucks? i know my 04 had an instant. Watching the instant litres/per 100km would be a good way to tell when your in a regen cycle no?

 

The 11s have just one - before I had the insight/Bully i would do a reset and it would let me know by the quick drop in average that it was in regen. I liked that on my LLY- the Bully and the CTS both have on driving coach mode.

 

I can tell when my 2012 goes into regen as compass does not work until the cycle is done. My first regen was at 650km after a highway run.

 

I'll have to look for this on my 2011, didn't notice it last time it was regen-ing.