Removing emissions controls

[MrNasty]

The def fluid goes in the exhaust and there is a 9th injector in the exhaust as part of the regen is to clean the dpf filter, but the egr valve still closes to keep the heat and soot in the motor i believe. To recirculate and reburn. Maybe im wrong but with a egt sensor in the manifold and the factory sensors it seems to get pretty high egt's during the regen.

[Colossus]

If it is not repossessed first, I'll likely end up trading my 2012 DMax in sometime in the next few years for either a low millage LMM or just go with a gasser again This 2012 sucks compared to the 2008 LMM I had previously.

[Cowpie]

The EGR does circulate more soot thru the engine, but that is independent of any DPF regen stuff downstream. One other aspect of the DPF thing is that it a regen is typically triggered by build up in back pressure to a certain level. This also leads to some excessive EGT's back up near the engine, and that has led, at least with many heavy commercial engines, to considerably more turbo failures, especially the VG type. Different engines react differently to all of this. It is never a good thing to feed a diesel it's own feces (EGR), and then purposefully create constipation by plugging up the colon (DPF). But from the greenie side of things, all of this does lead to cleaner air. As for particulates being a major problem from diesels, that is coming under more debate and scrutiny. Studies fo the LA basin show that particulate levels associated with internal combustion engine do not decrease during weekends, when there is far fewer commercial diesels operating. Gas engines are just as responsible for particulates, so you know it will be coming someday..... DPF's for gasoline engines.

 

Either way, it is expensive in terms of both initial purchase and lifetime maintenance for the emissions stuff. GM has kept the actual price on a Dmax pickup low compared to what it really costs for this stuff by spreading the cost around to other vehicles they make. If a Dmax buyer had to absorb the real cost of just what the emissions junk price tag is, sales would suffer quite a bit. They are already paying a premium for a more expensive engine and trans, adding several thousand dollars of emissions stuff would tip the balance in vehicle affordability. The emissions stuff alone on the typical heavy duty commercial truck reaches into $15,000 territory. I would have to guess that on the pickups, it is at least half that amount.

[MrNasty]

I have heard that the dpf tends to clog a lot. I know when I first had mine the nox sensors were always messing up and had to take it in three separate times for the nox sensors to be replaced. On the last one they had to replace the def tank and some other sensor (cant remember now) and thats when I decided to get rid of it.

 

I had heard some where that GM was going stop putting def in the 2017's but not sure if they did.

 

Im all for cleaner air but I hope they can make cleaner air without jeopardizing the longevity of our engines. Lets face it, with the prices vehicles are bringing they are turning into a major investment.

 

 

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[Cowpie]

DEF for the SCR is here to stay, as it is the most effective way to allow a diesel to operate well and reduce NOx levels. In theory and practice, I have no problem with the concept, just a problem with the design. A while back, a Danish outfit, Amminex, developed a way to put DEF in a salt substrate cartridge that would eliminate using the liquid DEF. Showed a high degree of promise. Simple cartridge replacement and it would eliminate the injector nozzle type of thing. The cartridge is heated electrically to release the DEF as needed as a vapor. Eliminates the freezing problem with DEF in cold regions also. Just pull a used cartridge out, and put a new cartridge in as needed. Considerably less real estate on the vehicle is taken up for the system compared to a fluid tank. Haven't heard lately where Amminex is with this design or if any OEM's are giving a serious look. They should.

 

Did a quick search and here is their page describing the technology.....

 

http://www.amminex.com/products.aspx

 

One aspect of DEF is that it is mostly water. It is 32.5% urea ammonia and 67.5% deionized water. The Amminex cartridge eliminates the water portion. The cartridge only has urea ammonia in the substrate. This eliminates many problems like freezing and degradation of exhaust systems. If GM would get with the program and look into going this route, the massive DEF tank would be eliminated, the associated problems would be greatly reduced, and customer satisfaction increased. And would keep the greenie nazis happy.

 

According to Amminex, being their system does not have the limitations of DEF/SCR technology currently in use, even EGR could be eliminated from diesels and still attain lower NOx levels. A win-win right there! And by getting rid of EGR, soot loading of the engine and oil would be greatly reduced and that would lead to fewer DPF regens. Why the OEM's are not all over something like this baffles the imagination.

[Colossus]

I just dropped my 2012 back off at the dealer for the DPF issues again. I'm tired of 80-120 mile regens. The DPF worked great on my 08 and I would get 450+ miles on a regen, I drove all highway during the regen process, and life was great. I expect the same from my 2012. We'll see what comes of it this time around.

[wrc7732]

I just dropped my 2012 back off at the dealer for the DPF issues again. I'm tired of 80-120 mile regens. The DPF worked great on my 08 and I would get 450+ miles on a regen, I drove all highway during the regen process, and life was great. I expect the same from my 2012. We'll see what comes of it this time around.

I hope I don't jinx myself, but I have not been aware of the regents happening on my '16 2500. It occasionally sounds as though maybe it's running one when I shut the truck off, but there's no indicator anywhere depicting that it's happening. I run it on the highway fairly frequently so maybe it does its thing while I'm bombing down the interstate, but I thought after 8k miles I would have seen an active regen by now.

 

Not complaining mind you. Knocking on wood that it doesn't cause me any problems like many are experiencing.

 

On another note regarding economy, my dad has a 2007 Duramax that I have always consistently got around 12 mpgs in. Maybe that's not normal but I'm not away of any issues with it. It's just thirsty. Perhaps I need to look at something. Almost irrespective of situation. But, In my '16 I regularly get 14 mpgs around town and have done as well as 19 mpgs at 75 mph on the interstate.

 

 

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[Colossus]

12 MPG on a 2007? That is pre-DPF so it shoulid be getting 18-21 on the highway unless he is towing. Something aint right.

[redwngr]

I hope I don't jinx myself, but I have not been aware of the regents happening on my '16 2500. It occasionally sounds as though maybe it's running one when I shut the truck off, but there's no indicator anywhere depicting that it's happening. I run it on the highway fairly frequently so maybe it does its thing while I'm bombing down the interstate, but I thought after 8k miles I would have seen an active regen by now.

 

Not complaining mind you. Knocking on wood that it doesn't cause me any problems like many are experiencing.

 

On another note regarding economy, my dad has a 2007 Duramax that I have always consistently got around 12 mpgs in. Maybe that's not normal but I'm not away of any issues with it. It's just thirsty. Perhaps I need to look at something. Almost irrespective of situation. But, In my '16 I regularly get 14 mpgs around town and have done as well as 19 mpgs at 75 mph on the interstate.

 

 

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There is no signal or indicator for when regeneration of the DPF is happening, since it is supposed to be a 'non-event' to the truck.

 

If it can't complete a regen over a long enough period it will give message to 'keep driving' or to get serviced.

[austingta]

In my truck the signal is clear...it idles at 1100 RPM and my mileage drops at least 25 percent. I recognize it every time.

[redwngr]

In my truck the signal is clear...it idles at 1100 RPM and my mileage drops at least 25 percent. I recognize it every time.

They sound different too.

 

But none of that is an indicator on the dash that say's ' I'm in regen '.

 

 

If you're running down the highway and not set for fuel economy.....

[X25]

Yes, it'll produce a bit higher emissions, but it'll get better fuel economy and won't require refined urea to operate. I'm personally not convinced the system does anything more than offset where the pollution comes from. Less pollution per gallon, but significantly more gallons burned...

 

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A bit? The emissions go up by 40 times or so when you delete the emissions equipment. There is a reason why all these different types of equipment are required to be able to run these engines.

 

Europe has traditionally had more relaxed emissions requirements for diesel, and they are now paying for it. The diesels running everywhere in Europe now create enough smog to block sunlight in metropolitan city centers, and the pollution agencies call it the biggest blunder of EU (besides handling of the 2008 crisis).

 

Anyway, my point is, deleting these trucks is like operating 30-40 trucks every day; the impact is huge. I don't think it's worth it for 1 more MPG, or more bragging HP/TQ numbers.

[X25]

The most cost effective change that would not be invasive and deliver most positive effect for the dollar is a simple shutting off of EGR via ECM code. Less soot, fewer regens, and usually helps fuel economy. EGR is controlled by ECM. Just have the ECM just not ever open it. There are already certain parameters where the EGR is reduced or shut off anyway.

Do you guys know if there's a way to disable EGR not by tune, but by, say, unplugging the solenoid, and attaching a simulator to the harness?

 

By the way, I'm not sure why EGR (disabling) would reduce regens. Wouldn't burning things again in high heat of the cylinder burn down the ash and reduce the particulates? I might be wrong on this; just wondering.

[Cowpie]

EGR will not reduce regens, but disabling it will.

 

History. Diesels were getting considerably cleaner with the advent of computer controlled engines and more efficient turbocharging. Not like the old smoke screen days. Then the Gooberment in it's infinite insanity decided that NOx needed to be reduced (not arguing with that) and EGR was the way to do it. The idea was to displace some of the oxygen in the cylinder, thereby reducing nitrogen/oxygen bonding (NOx). But, that also meant less oxygen for an efficient burn of the fuel. So more soot was created. This led to substantial soot loading of oil and even the cleaned up exhaust was now back to smoke screen events when EGR would kick in. So as opposed to your query that reintroducing the soot back into the cylinder would burn it up, it actually promotes more soot creation. The ultimate dog chasing it's tail.

 

EPA '03 brought us EGR on diesels. Now that they had screwed things up with that, they gave us EPA '07 which introduced DPF's to clean the excess soot out of the exhaust and burn it off via a regen. The first event, EGR, led to the second event, DPF, to clean the mess up they created. Of course, EPA '10 brought us SCR (DEF) to reduce NOx, which is the way they should have done it in the first place. But even with SCR, they left on the EGR requirement. They just can't admit they screwed the pooch with that setup. But, SCR did allow for EGR to be dialed back somewhat, and that has caused a reduction in DPF regen events since less soot being generated by EGR. By shutting down the EGR altogether, regens would be reduced even further leading to much longer DPF life and lower cost.

[X25]

Thanks for the explanation. Considering DEF hopefully does most of the reduction anyway, disabling EGR (hopefully without having to touch the stock tune) could be a great compromise for us.

 

The perfect mod would fool the truck (without any side-effects) that the EGR should not be opened, but I'm not sure how it could be done. Disabling EGR with a simulator in place of the solenoid plug might not be ideal, if the engine changes the fueling, etc. as well since it now expects the EGR gases in cylinders. I wonder if fooled altitude sensor or something similar could keep it shut without any other adverse effects, but it's hard to know without looking over all the tune tables and what kind of compensation tables the truck comes with. Perhaps someone who tunes these trucks could help on this.