GM Regen - Montana Owners Club

exav8tr · 11-16-2009, 03:51 AM

Didn't want to hijack the Ford thread so will ask here. I have a '08 Chevy one ton dually diesel with about 35,000 miles. I honestly don't know if it does the regen thing or not. Tailpipe is clean. How would I know if it is doing the regen thing or is that just the Fords????

Thanks Phil

ole dude · 11-16-2009, 04:19 AM

I also have a 2008 Duramax Chevy, and have asked several times if there is some kind of message to tell you when regen is occuring, no answer yet. Two things I do notice that would have me believe it is in the regen mode is, the fuel mileage drops off and sometimes when I stop and get out I smell something similar to kerosene.

Delaine and Lindy · 11-16-2009, 04:47 AM

Phil if my 2008 Chevy 3500HD ever regen I never did notice and it had about 25,000 miles. The only issue I have ever had with all the Duramax's I have owned was the Fuel filter. I really never had to go back to a Dealership, except for a bad electric seat. While in Gulf Shores last winter. I can't quite understand the problems some people are having with the Super Duties. I sure hope Ford has tested their new Diesel enough to get the bugs out. Its so very disappointing to get a beautiful Truck and have problems. I sure hope I have as good service out of my Freightliner with the Mercedes Diesel as I had with my Duramax's. GBY.....

Jolu · 11-16-2009, 04:48 AM

Same here as ole dude for our 08 Chevy. I get a strong smell of kerosene at times. Usually I will notice it when stopped in traffic. This has not happened all that often. So I am not sure how often regen takes place.

richfaa · 11-16-2009, 05:54 AM

You can take this to the bank...2007.5 and up,,,Ford, GM,Dodge.They all have the DPF and they all regenerate. Don't know about messages. Consulate your owners manual and it will tell you. I am almost sure the GM exhibits a "clean filter message" They all use the same technology. A google of DPF filters will provide some good information. There have been several computer upgrades on all the brands since 2007.5 so the frequency of Regen's may vary as well as the message displayed.. But...They do regenerate... Folks are having the same DPF problems with all brands so say the various brand forums.. The accurate way to see Regen's and the result and length of them is to have a after market gage were you can monitor the EGT, RPM, and MPG. Except for the message and the readings on my gage we can feel no difference in performance. We can see the difference but feel nothing.. We have..on occasion had the slight smell of diesel fuel..not all the time..

corncob · 11-16-2009, 06:05 AM

I have the 2009 Duramax and my brother has an 08 and both regen. See my topic on Duramax Mileage. Having said that it should regen on the ave of once a tank full (see owners manual). To date I have seen no message on the DIC. Nor a decrease in mileage. I firmly believe the regen works for those who leave the engine idle that allows the build up. Otherwise, not a lot of build up.

HughM · 11-16-2009, 06:52 AM

Ford may have the regen message or "clean filter message" but my Chev. Duramax doesn't have it or any of my friends GM trucks. It's automatic and I've never lost power or drastic drop in mpg during regen. I have a dependable truck and I just crank it up and drive it and only maintenance so far is LOF at 5,000 and fuel filter every 15,000. You can't get more depenability than that.
Hugh

richfaa · 11-16-2009, 08:15 AM

IMO most of the complaints about Regeneration problems are exaggerated by the user,any brand. If you could monitor the engine parameters you would see changes during regeneration In MPG, EGT. We will see a sight drop in RPM at the outset but that comes back quickly if in CC.Our MPG will drop @ 2/3 MPG during regeneration (Ford) and the EGT temps will increase 400 to 600 degrees while in regeneration. As with others we have never experienced a loss of power during regeneration. In reality all brands do the same thing. You have to experience a slight MPG drop during the time of regeneration as fuel is being burnt during the process that is not turning the wheels. I don't even think he same amount of uel is being introduced into the DPF during regen as at the very outset we may be showing 600 degrees EGT and it will jump To 1100/1115 (at 62/65MPH)
and stay there for a few mins then slowly decrease in temps as the regen goes on. I am no expert but that seems that less fuel is being used as time goes on. MPG wil also slowly come back up as the regen goes on????

TAKPAK · 11-18-2009, 02:10 PM

When we first got our '08 GMC Duramax, I was still doing intown driving. About every other tankful, it would go into regen, and then I would trail a very large amount of greyish smoke behind me. Downrigh embarrassing sometimes. First time it happened, I thought the turbo seal had gone. I checked with the dealer and asked if the smoke was normal. He laughed and said "oh yeah." It happened off and on for the first 10,000 miles or so, but since then I have not had any more smoke on regen. And yes, I know exactly when it goes into regen. The RPM goes up about 150 RPM on the tach, and I start smelling something "hot" under the car. But it all goes away shortly. It may be because since I retired, I don't drive the GMC as much, and when I do it's pulling the Monty, or going a distance. So, that may make a difference. No more stop and go driving. 21,000 on the truck now, and getting 11 to 12 MPG towing the 3400. I'm happy..........!

mcgiver2 · 11-18-2009, 02:34 PM

Yes like Rich said, (You can take this to the bank...2007.5 and up,,,Ford, GM,Dodge.They all have the DPF and they all regenerate.)I had my oil changed yesterday and i asked the service center that question he told me i would never tell it,but it does it, and he told me the you never see any differance in fuel mileage because its only for a short time

richfaa · 11-19-2009, 03:20 AM

Allen.. The dealer should have said that you will see no difference in overall MPG..You will see a decrease while it regenerates but if you are on a long trip it will at the end of the day indicate normal MPG..We get 10/11 towing at the end of the day...regeneration or not.But while in regeneration we can see, via the after market gage, a 2/3 MPG decrease in MPG.

flstf · 11-26-2009, 10:47 AM

I have an 08 3500...the first 27,000 miles it regen'd on average every 385 miles. This historical data is stored in the vehicles ECM and can be viewed using a scan tool (EFI, HP tuner, OTC stuff...).

take care,
Joe

RCN.Stoker · 11-26-2009, 11:27 AM

2009 and other than the occasional smell the only way I can tell is temperature. Put a gun on the exhaust aft of the filter and you will see why parking over dry grass may not be a good idea. Normal regen takes place in driving as long as the temps are high enough (I believe about 600F) and you drive for about 25-30 minutes. The only time the GM gives a message is if you have not regenerated through normal driving and the filter reaches a preset limit of soot accumulation. If you don't then create a regen by taking it out on a highway and running it at 80kph or higher for the required 1/2 hour it reaches the next preset and goes into a form of "limp" mode.

FWIW I have never seen any smoke and doubt that this is a normal condition.

clutch · 11-26-2009, 05:49 PM

My truck is a 07.5 Dodge and there is no message when a regen takes place. I know when it is happening because my pyrometer will jump right up to 1250+*. Even driving the empty truck at 60 on a flat road the pyro jumps right up there. It dosen't happen very often but the pyro tells the story.

To watch the pyro climb that high for no reason is kind of unnerving at first. When it happens I back out of the throttle when it gets close to 1300*. People without a pyro just don't have a clue what kind of temps are taking place.

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