What to expect for typical EGR/DEF/Nox issues as the truck ages.

[MichaelOverfield]

I'm relatively new on TDR, I'm on my 3rd Diesel truck first 2 were Duramax, the last one a lemon.. but it was mostly due to the 2007 MY emissions added in that year. I really miss the 2005 and a mostly NO emissions engine, with a ZF manual transmission.. in any case when GM bought back the lemon I went back to my preferred manual transmission, and Dodge is the only Diesel pick-up that still has this option. In 2009 it was possible in Ford, but who in their right mind wants an engine that would only have 3 years total in production? This left me with Dodge, due to a prior 1997 Dodge Gas 1/2 ton that ended up a lemon also.. I was reluctant to go Dodge again, but the Cummins engine kind of negates most of my concerns.. so I went for it.

My truck is low miles, about 28,000 original miles, in almost 6 years.. one of the reasons for this, is knowing the limitations of the DPF/Nox system, I generally only go for longer drives, and when towing an RV, as to ensure the stupid emissions stuff does not clog up, and so far it seems to be issue free (also I use the block heater when I do winter drives, so as to not start cold iron). I've never seen the console indicate anything other than system OK. I only once had a trouble code when still under warranty, and the dealer cleared it, but could never explain how my truck threw a Auto only truck code, when mine is a manual!! But it has not come back, so that is good. My daily work commute is via beater car, but I really would rather drive the truck, it is stupid having a vehicle with limited utility thanks these new emissions requirements.

I've been looking at what lies ahead, I'll be changing out the fluids in the differentials, transfer case, and transmission soon, and upgrading the covers to next time I can drain via plug vice removal of the whole pan..

I'm aware of the coming EGR/filter service and some of the craziness to expect there.

What I'm looking for here are experience based opinions on paths going forward, I've been interested in possible options if I were to start having some of the dreaded issues. Seems there are some options out there for programmers and such. I'm quite happy with the stock performance level, but any improvement in economy would of course be nice, I know the regen process dumps fuel to the exhaust, and there is no way to tell me that won't lower economy, because it is simple math! Not to mention its affects on fuel dilution of the oil, and the need for more oil changes at 3 gallons at time!(in my low miles case, once a year, even if not near the required miles or oil monitor)

 

[xcc_rider]

Based on what I've read and seen stick with the Fleetguard or Mopar filters (Mopar filters are rebranded Fleetguard filters).
Geno's garage has good prices on them.


EGR service is a really good idea. If you don't clean it then it can get clogged and stick open. Read below for why its bad.

As for the exhaust, you shouldn't see problems if you have the J35 flash and dont use it as an errand/grocery getter. I used to commute 50 miles each way in my truck and didn't have any problems for 50k miles.

With that said, I've had two instances of egr valves sticking open on me while towing and terminally plugging the dpf. I finally unplugged the egr valve actuator about 20k miles/3 years ago and haven't had an issue since. There's some write ups on doing this so you can read up a bit on the pluses and minuses of doing it. I like it because I picked up 2-3 mpg and my oil stays clean now (like it should be).

If you're able to delete then that's the obvious choice. Get rid of the problematic equipment and you don't have problems.

 

[Tuesdak]

I DON'T miss my 2005 LLY Duramax with the uncontrollable and unpredictable hair trigger throttle and, well, a 1993 modified 6.2 diesel turbo can outrun it towing through Death Valley. Not hard when the LLY is on the side of the road overheated. There is video of a 1st gen Dodge Cummins outrunning a LLY for the same reason. (Yes one of the s#ittiest diesels ever made can outrun a LLY Duramax. Only because the cooling issues on a 6.2/6.5 can be solved with mods unlike the LLY POS.)

2008 Duramax appears to have most of the issues resolved except lugging the engine in 6th (auto) and spiking the ECT through the roof on light grades. The 2007's were prone to EGR's blowing open just off idle and DPF plugging smoke without power. The only way to stop the EGR is a blocker plate as they blow open even disconnected from the electrical connector. (I guess that Cummins EGR's have the same issue.)

Note that blocking the EGR will spike NOx and reduce DPF plugging PM. Warranty = void at this point as you will need a tune. Deleted I have seen 10% or more better MPG on GM stuff. But you didn't buy a 1 ton for MPG... (Deleted as I was running B99 that diluted the engine oil during regen. Long story.)

If it was me I would check with the dealer and make sure you have the latest ECM flash as these solve issues. Then if your daily drive is long enough to warm the engine up - use the truck. See what kind of issues come up under warranty. Then take it from there. Reliability if you have trouble is a reason to walk over to the Darkside.

You could even consider trading up the the DEF 2013+ trucks that have less issues and better MPG with the emissions equipment.

Prior to DEF use the systems have to use lots of EGR to control NOx. Lots of EGR results in lots of soot that plugs the DPF that then has to burn out wasting fuel. The soot also plugs up coolers and the turbo. You would think that a long hard pull up a grade would burn out the DPF - WRONG! Full power requires so much EGR for NOx control that the DPF will be in regen at the top of the hill. So every time our 2008 would pull a grade and then deliver parts in town at the top of the grade it was in that stinking regen in town. Watching the exhaust pull the hill deleted it was no wonder as it smoked worse than a NA 6.2 from all the EGR choking the #ell out of the engine. Till the EGR got a blocker plate that is... Cleaned the exhaust up and with B99 use put NOx through the roof. (Visible emissions are more important than anything else because belching black smoke IS the reason we have tighter diesel emissions than the European Union.)

The DEF systems solve the excessive EGR use by using DEF to control NOx instead.

 

[MichaelOverfield]

Thanks for the replies so far.. exactly the wisdom from experience I was looking for. I guess I never saw the dark side of the 2005 LLY, as it was killed by a collision when the truck had a mere 14K miles on it at 2 years old.. that and my trailer and typical loads are not then, nor now at capacity... but good to know in any case.

Interesting take on the DEF trucks, I figured there must be a reason the OEMs are now all going that direction, but DEF then has the issues of shelf life/freezing, and I hate that the ECM disables the truck over a DEF issue.. that and economics of a new truck puts me out of the DEF option.. trade some problems for different problems it seems.. all to stop a problem that is likely not a really problem in the first place.. but I could rant all day about that!

I'm pretty sure I have the J35, with the recall on the track bar that was installed, I do get the high idle on occasion when I'm running the truck prior to departure on colder days.. I believe that was part of the J35 programming fix. Having said that, I think use of the block heater is likely wise to minimize idle in general.

Good call on Geno's, got parts from them already.. front diff cover for the coming fluid change. I like the kits they have for the maintenance intervals.

On the EGR, seems to be a problem with all the Diesels.. my neighbor had problems on his Ford with this, and did the delete, it has been fine since. Not sure what programming he had to do, but I imagine something on the electrical end to avoid the warning lights..

 

[MichaelOverfield]

I guess I should add some of my prior observations on EGR and emissions.. the Nox in Diesel engines comes from the normally high temperatures of combustion, that and greater energy density of the fuel enables the higher efficiency of the engine, the EGR is there to reduce combustion temperatures to reduce Nox, it does this by literally choking the engine of Oxygen.. isn't that Ironic right there. Similar on a Gas powered engine with an EGR, but gasoline not being a compression engine has lower Nox and temperatures of combustion naturally.. so less need for the EGR, that said the dumb thing still sticks on my beater car occasionally, and it is annoying (already replaced it and cleaned the soot in the engine, still get it on occasion, but it clears.. so I mostly ignore it.

The EPA and others are convinced that too much Nox will make smog problems, as it is a issue in places like LA, but the bigger issue there is really the geography and prevailing winds.. but never mind that, they impose standards upon all of us just the same. The visible soot is something that they claim is causing asthma attacks etc. but there were less issues previously with much more contaminated air, so there is something else going on their that is not being addressed. The soot is mostly carbon and eventually is deposited and pretty harmless.. but never mind that, they charge forward to literally impede improvements in reliability and efficiency. Even that 2005 LLY made minimal smoke on a hard acceleration, and no DPF needed. But now we have all this crap, and lower economy, more issues and literally I maintain a separate vehicle as a daily driver because I'd have issues using my truck for this, and because I drive a small economy car, I'm less safe.. that 2005 truck took a very hard hit by a speeding SUV, I got out without a scratch.. had that been my Saturn I don't think I'd be here today..

 

[Tuesdak]

Had first class tickets watching a family member recover from a near fatal "mid size" car wreck. 5 years later they are finally able to go back to work. I lost count at 26 surgeries. Yes CA needs to dynamite a couple mountain ranges to stop the air from being trapped in the valley aka LA and the central valley. Not a fan of coffin on wheels cars esp with Elk and other critters on the roads aside of other vehicles. MPG does not matter to me when you look at 6MPG for 1 million miles doesn't even touch the medical expenses of the above wreck.

Trying to compete with the older trucks with the lower fuel economy of the 2008 wasn't fun.

The DPF is so fine that is is actually a secondary air filter so running a K&N or other inefficient air filter will let more DPF plugging dirt get trapped in the DPF that can't be burned out.

Again I would run it and see if you have issues with it.

 

[MichaelOverfield]

I just installed the UltraGuage EM Plus last night.. one of the monitors is for EGR position, and EGR error (that occurs with the command and position don't match, as in stuck valve). This little gem of a device has up to 55 monitoring parameters for my 2009 truck, that and 7 pages of displays with up to 8 parameters per page.... it is going to take time just to figure out which parameters I want most! (it was less than $100 with mount and shipping... a good buy).

From my initial drives thus far... I discovered an interesting operating pattern on the EGR.. it was typically open at 94% when at idle, then as soon as I was driving, even a low load, it went and stayed at 0%... perhaps this explains the problems with idle in part.. those who have had a stuck EGR wipe out the DPF... well, if the EGR is open most of the time at idle, and it adds to soot levels going to the DPF.. (one would have to think it does.. it is to lower NOx by lowering combustion temperatures in the engine, but starving it of O2, which causes incomplete combustion, which is the source of soot!! Somehow this seems like a poor trade off.. lower NOx, but increase soot, and decrease efficiency?

I'm seeing that the EGR alone is problematic, and as others have stated, the truck likely will perform more efficiently with it kept closed.. amazing that someone thought it was a good idea in the first place.. Just a bit of Engineering thermodynamics would have demonstrated the loss of efficiency.. but this was done not by logic, by politics.. evil NOx you know.. The higher temperature an engine can safely operate under, and lower the environment temperature, the higher theoretical efficiency that can be attained.. this is why old steam ships could attain higher speeds in cooler sea water to the condensers.. for the diesels, the colder intake temperatures and temperature difference from the air to the coolant, more is better. Limits on the top end temps are normally set by what the materials can handle (engine components, coolant, etc.).. but one can go back over the decades in automobile engines and see the higher coolant operating temperatures as the materials got better, these higher temperatures allow for greater efficiency of the thermal engine (a 140F thermostat was typical in the 60s, now 185F or more is common).

To put in an EGR is to intentionally lower the combustion temperature to reduce NOx is to intentionally take an efficiency hit also. The reaction that creates NOx occurs at elevated temperatures, and since diesel combustion occurs at higher temperatures than Otto combustion (Gasoline engines) it is the smog concern on Diesels, but we are literally taking an efficiency hit to get there, and that means more CO2, for those that really think that is an issue too.. the whole thing is insane!

 

[xcc_rider]

Sounds like you've done a good analysis of the egr system. What have you observed over the longer term, at constant freeway speeds and during an active regen cycle? As I understand it the egr opens at freeway cruising and during the regen cycle too.

 

[MichaelOverfield]

I've just begun analysis of EGR in operation. Seems open when at idle is standard. When at operating temperature, open while at cruising speed/highway.. Begins closing when throttle is opened, or deceleration. That fits with pattern to control combustion temperature which drives Nox production. On the ultraguage, there is also and EGR error alarm. It commanded position varies by more than set alarm limit it alarms.. I set 20% and it alarms often.. Tells me that valve cycles often. It also confirms taking out EGR could be a reliability improvement.

 

[xcc_rider]

Keep us informed on what you observe. No doubt the valve is a pos. Only reason I'm only on my second one is that its unplugged and can't stick open on me anymore.

 

[MichaelOverfield]

OK, a few more observations on the EGR. The ultraguage is informative (though I have a issue I need to address with it periodically shutting down.. more to follow).

I have the alarm set to tell me when the ECM value differs from the EGR position by 20% or more. It is getting quite annoying.. because it alarms so often. This is indicative of 2 things:

1. The valve is changing position OFTEN
2. The valve changes position with considerable lag from the command signal, either this is normal, or the valve is starting to bind, and I have only 28K miles so far).

I can also monitor the temperatures of the NOx absorber and DPF, and from that determine Regen. I've seen it go into ReGen, and temperatures up to 1200F (normal highway is about 600F or so). When in Regen, I could see a very noticeable dip in MPG, because the 1200F comes from that post injection cycle where thanks to the EPA I can increase fuel use and CO2 for the sake of lower soot and NOx.. not sure how wise that trade really is. Suffice it to say, the ability to see all this is quite helpful

I'd be interested in more information on how to deal with the EGR.. If I disconnect it I'm sure CEL is going to come into play.. I know there are some programmers that can deal with this and even eliminate other components.. I think I'm likely to want to just deal with EGR when/if it becomes an issue for now.

 

[xcc_rider]

There's been a lot of experimenting done already with the egr system and besides tuning the only viable option is to unplug the egr valve and live with the cel and P0405 code. Read here: http://www.cumminsforum.com/forum/0...-egr-test-results-finally-completed-read.html
And here: http://www.cumminsforum.com/forum/6-7l-tech-articles/92997-unplugging-your-egr-recap.html

As for tuning, H&S, TorqueTech, and probably EFI could disable the EGR system alone and keep the exhaust components fully functional.

 

[MichaelOverfield]

Ok, so I think I finally got the Ultragauge to stay on, apparently there was an intermittent connection on the OBD II connector, pin 16 on the truck side, as it worked flawlessly on two other vehicles.

I wanted to have this in place so I can monitor codes, since I'll likely have the P0405 locked in and CEL on when I unplug.

So I unplugged EGR today, and reset the fuel economy counter.. with just one short 20 mile drive and CEL ON, P0405 as predicted, I got an average of 26MPG about 4 MPG higher than before on the same drive under the best conditions.. and I was liberal with the throttle a few times, and still came in at 26MPG.

 

[xcc_rider]

It would be interesting to see what your hand calc is for the first tank full.
(I know you know not to trust the lie-o-meter)

 

[MichaelOverfield]

True, I know the lie-o-meter is quite generous, but I compare the before and after and the differential should be a good indictor. With the 45 Gallon Aux tank, it can be a massive time before I use a tankful !! and I have to factor in any other vehicles I might decide to fuel up with the filler pump.. I often fill up the Jetta for my wife, as it uses so little fuel.. 10 gallons is good for near 500 miles in that car.. With all that said, the before EGR unplug, I have solid tank calculated fuel economy for my last RV trip... it was 975 miles, and 84.84 Gallons total, which came out as 11.5 MPG, towing. I the lie-o-meter had it about 12.4 or so.. not too bad considering the it had some not towing averaged into that number.

If all goes according to plan, I may have another long RV trip coming up soon where I can compare towing mileage, directly before and after. I still need to get that freeze plug and fully block the EGR as noted on that thread you linked earlier.. seems that is to make it an even better mod.

One other interesting note, the Ultragauge does fuel mileage computation also, but it is WILDLY inaccurate thus far.. it needs calibration with actual distance and fuel used to get more close, but I think it has a computation issue on this truck.. It appears to calculate fuel flow, from mass air flow, and it ramps up fuel rate with the exhaust brake (the exhaust brake DOES ramp up BOOST pressure, so the apparent mass air flow goes up too, but I do not think the injectors dump more fuel, in fact I know they don't as the fuel rail pressure does not ramp up.. but the ultraguage does not thus far seem to account for this..) so I'm going to have to deal with it at some point, but it is not the primary reason for this device, so it is not a priority.. though it does suggest that the reason the lie-o-meter may well be inaccurate is because it likely also uses some form of calculated fuel rate based on mass air flow and other parameters.. I don't think the truck has an actual no kidding fuel flow measurement, and besides if it did it would need 2, one supply and one return to calculate the difference. (since I recently added the severe duty second filter system, I know there is not fuel flow device in either the supply or return lines). Many years ago I had a fuel economy meter on my car which had an actual flow meter to determine fuel rate, and it was pretty accurate, but that was a simple carbureted vehicle where one fuel line was all it had.

 

[MichaelOverfield]

So some on road driving does confirm a 1.5 to 2 MPG gain, comparing the lie-o-meter before and after. The measured fuel consumption matches.

Of note, now being able to see the regen by the 1200F cat temps, I can also see the MPG numbers take a hit at the same time.. these Regen events do cost measureable amounts on MPG.

That said, I went from 10 -11 MPG towing at highway speeds (65-70MPH) to about 12.5 MPG. Back roads.. (45-55 MPH) I got about 14.5, when before I'd be lucky to get 12MPG.

Without a tow, the hwy number had settled at about 21MPG, where before about 17-19 was typical ( I was going over 22 when regen kicked in and knocked it down to just under 20! I literally could see the number dropping)

It is now very clear to me why VW cheated after seeing how dramatically negative some of this emissions control systems are for MPG. I'm told the DEF SCR systems are much less EGR and thus more efficient and better MPG.. so there is that I guess, and I'll see with the new Chevy Cruze Diesel in my own real world testing!