i borrowed a friends truck 08 lmm 2500 cc,towed a 2 car open trailer,this is the most hindered slugish truck ive ever driven,[my 06 lbz would eat this thing for lunch]in the last week its gone into regen 5 times and keeps saying ''service exhaust filter''so when i got back to the shop i got out my tech2 and scanned the truck and had 14% soot,so i forced a regen on it,well after 25 mins at 2500 rpms and 695-745 egt temps it runs better ,but it still feels sluggish,are all these trucks like this?,,what do you guys that haul do to get these things to run better
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forced regen
- Thread starter dmaxx3500
- Start date
chrisk1500
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To run better I dumped the DPF and bought the Edge Evo Race....fixed the sluggish feel and the mileage...
"Service" means just that! "Clean exhaust filter now" is more likely. But if it does say service there may be a broken DPF sensor line. Look at the exhaust for the 1/4" lines to the sensor and check em out. Had mine fixed under warranty.
Look up killerbee and his tunes.
Learn from and met the local to me guy. The EGR setup on the 08 is the source of your bog. Tune the EGR out or block the damn thing.
Hard work/throttle like towing will open the EGR and smoke plug the DPF. Pulling a hill into a city and then city driving was always regen in the city. I watched this steady smoke when I lost a kitty and misplaced a DPF. After the tune featuring no EGR and 'I don't care what blows up' - There was smoke till the turbo spooled then the smoke cleared up and was replaced by tire smoke.
Canned tuners also will bog you till you get RPM up. Same off road exhaust smokes like crazy and no low end power. That is till you block the EGR. Then it was a raped ape. (Friend finally used a blocker plate with his canned tune.)
Point is the LMM will run smokeless with EGR removed. NOx is out of control, but... Smokeless under load like towing and no EGR. Add EGR and the engine starts to smoke. smoke plugs the DPF requiring a regen...
GM does not have DPF and EGR figured out in 2008. Because the hill pull with a trailer should self ignite the DPF regen process... Instead GM wastes fuel doing so in the city... GM went cheap and skipped the exhaust injector. Added in later models and I do not know how well it does. Theory is you could light the DPF on a hill climb and burn the soot she is putting out as fast is it is coming out.
Welcome to green religion hell - diesels will never run right again.
Look up killerbee and his tunes.
Learn from and met the local to me guy. The EGR setup on the 08 is the source of your bog. Tune the EGR out or block the damn thing.
Hard work/throttle like towing will open the EGR and smoke plug the DPF. Pulling a hill into a city and then city driving was always regen in the city. I watched this steady smoke when I lost a kitty and misplaced a DPF. After the tune featuring no EGR and 'I don't care what blows up' - There was smoke till the turbo spooled then the smoke cleared up and was replaced by tire smoke.
Canned tuners also will bog you till you get RPM up. Same off road exhaust smokes like crazy and no low end power. That is till you block the EGR. Then it was a raped ape. (Friend finally used a blocker plate with his canned tune.)
Point is the LMM will run smokeless with EGR removed. NOx is out of control, but... Smokeless under load like towing and no EGR. Add EGR and the engine starts to smoke. smoke plugs the DPF requiring a regen...
GM does not have DPF and EGR figured out in 2008. Because the hill pull with a trailer should self ignite the DPF regen process... Instead GM wastes fuel doing so in the city... GM went cheap and skipped the exhaust injector. Added in later models and I do not know how well it does. Theory is you could light the DPF on a hill climb and burn the soot she is putting out as fast is it is coming out.
Welcome to green religion hell - diesels will never run right again.
i can't believe people aren't raising hell with dealers ,this is the biggest POS ,how can anybody use these trucks to haul anything to earn a living,I'm going to fix this,but i just got home after an 15 mile drive under ''reduced power'' [ took 45 Min's] these things are dangerous to drive when they go into ''regen'',i just drove an 2011 lml and now i think i'll find an 2007 classic instead,
killerbee
Member
I would venture a guess that someone has messed up the tuning. You are describing what an LMM acts like when post-injection is disabled. EGT should never reduce below 1100 during the regen. If it does, soot reduction crawls to a stop. The post injection is one of 3 key ingredients to regen effectiveness.
Just a guess, ask me how I know.
As I recall, there also was a bad flash in early 07.5 and/or 08 factory trucks. EGR should remain off during regen, if you have a way to watch it. EGT cannot get hot if there is no O2, and EGR was a regen inhibit problem. Lots of complaints of very poor economy, and frequent filter messages. There is a dealer update to it now that resolves the issue.