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Discussion Starter #22
There are a lot of YouTube video's on how to clean your DPF with a power washer, most being done on big-rig trucks. Even if you don't do as good a job as a professional flush, if you can DIY and get 30K, it's probably worth saving the $300. I assume you have to cut the DPF and bring it to the flush place and then reinstall yourself. If they did the removal, flush and re-install for $300 I'd just have them do it.
So the DPF is actually nicely bookended with flanges and gaskets IIRC. Removal to get to it and pressure wash it is possible. I'll have to see what these self flushing videos look like.
 

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Discussion Starter #23 (Edited)
Hi
My 2017 Colorado Diesel has 36,000 miles on it. I have had it serviced at the dealership . I have also had to replace the DPF twice. The first time was before 15,000 miles and the second time last month at 35,000 miles. This time they replaced the filter, EGT Sensor, erased all DTC's and performed a Regen. Now after only 1000 miles I am getting an engine light and Reduced Engine Performance indicator on the dash. When I first saw the engine light and Performance indicator come up, I topped off the DEF fluid thinking that may be it, it wasn't.
Is this an issue with the DPF a common problem with these diesels? Has anyone had the same difficulties with this DPF and is there a REAL fix ? Don't really know what a REGEN is or how to perform one, sounds like a re boot.
Thank You
I've had 2 Colorado's a 2017 I totaled at 61,000 miles and this 2018 that made it to 70000 before I had any trouble with the DPF. I don't think it's a super common problem, but it looks like it can be a symptom of non-intuitive other issues because it catches the soot at the end of the tail pipe. Lots of things can cause a diesel to burn dirty. For example, if you got bad diesel it'll burn dirty pluging the DPF really quick. Clogged injector? That can cause clouds of black smoke too. Turbo leak? Yup can cause a dirty burn, Wack O2 sensor? Dirty burn possible. Even a bad tune that injects too much fuel can case a sooty exhaust. Basically anything that can cause the engine to burn dirty can clog the DPF and if the DPF gets clogged to frequently it throws the code. If none of those other failures are throwing codes in the engine it can be an absolute nightmare to troubleshoot.

As for what a Regen is I can help there. The DPF is a filter in your exhaust, specifically it is a Diesel Particulate Filter (hence the DPF acronym). It keeps the clouds of partially burnt fuel and soot from your engine from making it to the air. This is important because lots of testing has proven the particulate causes cancer and haze and other nasty stuff for the environment. Fortunately someone figured out that telling a customer to crawl under their truck every 500-1000 miles and replace a filter would get old quick, especially because the filter won't be cheap so it can withstand the heat of exhaust. So they engineered a solution to raise exhaust temps high enough to incinerate the particulate in the filter automatically when the filter gets full. This incineration process is referred to as a Regeneration aka Regen for short.
 

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Discussion Starter #24
Last post for today I promise.

It's been a couple weeks, burned through a few tanks of diesel, and I wanted to give an update for the next guy who stumbles on this post. Good news is I think I fixed it, bad news is unfortunately I can't give a straight answer as to what fixed my issue. I made the classic mistake of changing more than 1 thing at a time. After making my initial post I did discover that my ODBII tool could show my average mileage between regens. The average was abysmally low, at 203 miles. The "healthy" average I've seen on the forum here is in the 400-450 range.

The 1st thing I did was, as I mentioned in a previous post, swap the DPF Differential Pressure Sensor with a new part from RockAuto. Because the ACDelco part was on back order I ordered this one....https://www.rockauto.com/en/moreinfo.php?pk=10958356&jsn=881. It was super easy to install, though you will need some hose clamps to replace the factory ones that I couldn't get back on. I like the spring clamps and used some from my assorted clamp set from Harbor freight. After changing the sensor I kicked of a regen using my ODBII tool and the percentages fell in a linear fashion, no more jumping up and down and all around. This makes me believe my sensor was misbehaving.

2nd item I changed was I applied my Green Diesel Tune with the Regen notifications enabled. I am positive this has changed my driving behavior during regens. Before I'd have no idea it's happening so who knows what I would be doing. I probably even interrupted them by turning off the truck. Now I keep the truck on to let it finish, if I'm close to the highway I'll even try to get on it. During the process I had mentioned my DPF trouble to the GDE engineer and he said he thought the tune would help with soot loading before sending me the tune. No idea if it is helping or not.

3rd item I changed I didn't even realize until yesterday. At the start of this saga I had run out of marvel mystery oil and never remembered to grab any during my road trip or the weeks afterwards because I was distracted with the truck misbehaving. I have a religious habit of dosing my diesel with MMO to keep the fuel pump lubricated. The new Ultra-low Sulfur Diesel has terrible lubricity and project farm has proved MMO does help add some back. If in a couple weeks I find my regen cycle is all out of wack again I'll take the MMO out of the fuel and see if it helps. If it does help I'll update again, if it doesn't then I probably won't. AKA no further updates on this front means MMO doesn't make a difference IMO.

4th item I changed was a hose clamp on my intercooler line. One of the connections to the intercooler was covered in soot when I went to change my oil. I'm not sure when the hose clamp loosened up and I never saw any exhaust come out of the connection at idle, but it clearly was leaking at some point. I stuck a screw driver to the clamp and it had an extra 3/4 turn available I could twist in. I've wiped down the connection and I've not seen any new soot accumulate on the connection, but it hasn't even been 500 miles yet. If it had been causing a leaky turbo that defiantly could have been messing with the DPF soot loading.

So with all these changes what does my average look like right now 3 regens in? 605 miles on average between regens. I've been doing a bunch of highway driving trying to get miles on the truck so I can have a semblance of an answer. I'm sure that's put my average on the high side, but I think everything in the DPF is back to normal.

Which brings me to my next question for the hive mind.....what do you use to watch the stats of the truck the DIC won't display? My ODBII tool is a little obnoxious to set up every trip, and I know there are some other options that will remember what truck I have and just show a few bonus gauges. Any suggestions folks?
 

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Hi all, as mentioned I too have low mileage between regens. I towed my enclosed trailer from NJ to Ohio to move my daughter into college, 900 mile round trip. Normal driving I have been averaging about 120-150 miles per regen with some highway but mostly 30 minute local driving when not towing. The trailer weighs maybe 4000 lbs. On the way out I got terrible regens, I was regening about every 120 miles, then 20 miles to actually regen. Then on the way back I topped the tank off with about 12 gallons of fuel and started back, to my surprise I got over 300 miles on that regen. I had thought maybe it just needed a bunch of regens in quick succession to really clean it out. I know the previous owner only used it for local driving so maybe it was really sooty for the 16,000 miles he owned it. When towing my EGT’s (bank 1, sensor 1) average about 800-850 degrees and the DPF EGT is in the 600’s. It regened 3 times on the way out when towing and then while I was in Akron before my trip home. Soot load when I started my trip back was about 30%. After I filled up in PA on the way back I made it about 150 miles to home and the soot load was at about 95%. I haven’t tried a long non-towing highway drive to monitor things. In the week I have been home it’s already done one regen cycle at about 140 miles so I think it’s back to doing what it did before. The only thing I can think of for that 300 mile regen cycle on the way home was when I topped off before leaving Ohio I didn’t add any additive to the tank. I’m using a mixture of Standyne performance and lubricity. I’m mixing because I have left-over from my other truck I’m using up. I mix a ratio of 2:1 performance to lubricity. I put in 8oz of the mixture per tank (~5oz performance, ~3oz lub) which is the recommended ratio for a 20 gallon fill-up. I don’t think I’m using more than recommended but it is strange that the only time I didn’t add it I got my longest regen cycle. I may try not putting any in next fill up and monitoring my regen’s.



I am due to take it in for one of my free oil changes so I’m going to have them take a look at it. I’d like to first see if not using any additive makes a difference.
 

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Last month I asked if anyone has had as much trouble with DPF and emission system in general. I dropped the truck at the dealership while in Reduced Engine mode. This is 3 weeks after they replaced the DPF filter and exhaust system for the second time. So the engine light and Reduced engine mode was for the EGR Cooler Temp. sensor needed replacement. Well I can finally pick up my truck on Tuesday. No dealership or rock auto.com had the part. My question is for everyone, My warranty will be up soon and the track record I have had with this emission system is not good. Is this an ongoing problem that everyone is having or do I have a lemon? I will be retiring within months and look forward to pulling a travel trailer around the country, thats the reason for buying the diesel. Don't want to go through this every 6 months. I am tempted to trade it in for the 6 cal. gas Canyon.
Any thoughts?
 

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I've had 2 Colorado's a 2017 I totaled at 61,000 miles and this 2018 that made it to 70000 before I had any trouble with the DPF. I don't think it's a super common problem, but it looks like it can be a symptom of non-intuitive other issues because it catches the soot at the end of the tail pipe. Lots of things can cause a diesel to burn dirty. For example, if you got bad diesel it'll burn dirty pluging the DPF really quick. Clogged injector? That can cause clouds of black smoke too. Turbo leak? Yup can cause a dirty burn, Wack O2 sensor? Dirty burn possible. Even a bad tune that injects too much fuel can case a sooty exhaust. Basically anything that can cause the engine to burn dirty can clog the DPF and if the DPF gets clogged to frequently it throws the code. If none of those other failures are throwing codes in the engine it can be an absolute nightmare to troubleshoot.

As for what a Regen is I can help there. The DPF is a filter in your exhaust, specifically it is a Diesel Particulate Filter (hence the DPF acronym). It keeps the clouds of partially burnt fuel and soot from your engine from making it to the air. This is important because lots of testing has proven the particulate causes cancer and haze and other nasty stuff for the environment. Fortunately someone figured out that telling a customer to crawl under their truck every 500-1000 miles and replace a filter would get old quick, especially because the filter won't be cheap so it can withstand the heat of exhaust. So they engineered a solution to raise exhaust temps high enough to incinerate the particulate in the filter automatically when the filter gets full. This incineration process is referred to as a Regeneration aka Regen for short.
Thanks for the explanations. I actually have the Canyon not Colorado, my typo. Well the EGR temp. sensor that went bad may be the reason for the clogged DPF. Although I would like to keep the diesel, I am a little skittish due to the past history with the emission system on the truck. If my extended warranty will cover the DPF then I will most likely keep it at least till that ends.
Thanks for the input.
 

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I watch my regens and DPF percent very closely.
what I notice is 50/50 city highway I get 300 miles between regens.
I noticed that anything below highway speeds and the DPF fills up very fast.
only highway running seems to keep the time between regens at approx 1 per tank.

I thought pulling my trailer at between 5000-6000 lbs on the highway would keep the DPF hot enough to extend the regens. But that’s not the case. When pulling a heavy load your deep into the throttle making lots of soot. Filling the DPF faster than the high temperatures can burn off the soot.

I think what’s killing the DPF is allowing crank case oil vapour to be reburnt in the engine.
At least that’s what I am thinking.
An oil catch can or other option for keeping that oil from being burnt is essential......

Rob
 

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I watch my regens and DPF percent very closely.
what I notice is 50/50 city highway I get 300 miles between regens.
I noticed that anything below highway speeds and the DPF fills up very fast.
only highway running seems to keep the time between regens at approx 1 per tank.

I thought pulling my trailer at between 5000-6000 lbs on the highway would keep the DPF hot enough to extend the regens. But that’s not the case. When pulling a heavy load your deep into the throttle making lots of soot. Filling the DPF faster than the high temperatures can burn off the soot.

I think what’s killing the DPF is allowing crank case oil vapour to be reburnt in the engine.
At least that’s what I am thinking.
An oil catch can or other option for keeping that oil from being burnt is essential......

Rob
Thanks for the input Rob. I never thought owning a diesel would be this complicated. I chose the diesel for the ability to pull a travel trailer easily and still get decent gas mileage. I don't know much about oil catch cans but my first thought is will it alter the warranty. It sounds like the catch can is basically catching the oil vapor and then letting it escape into the air??
Thanks again.
Mike
 

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I was under the truck yesterday cause I was thinking of wrapping the pipe and maybe the DPF to keep the heat in. I'm not 100% sure what I'm looking at but it appears that the last round thing in the exhaust pipe system is the DPF, maybe located between the front and rear set area? Pretty far back. It seems the 5th injector is injecting directly into the exhaust pipe about 2-feet in front of what I think is the DPF? Although the pipe looks nice, the DPF must be coated steel because I find pits of rust starting. Is this correct what I'm looking at? Also explains why when it's raining I see very low DPF temperatures in comparison to exhaust EGT's. Might need to look at making a splash-pan to try to keep cold rain and snow from kicking up on the DPF. I just figure if things stay hot it's gotta be better. Thoughts?
 

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Thanks for the input Rob. I never thought owning a diesel would be this complicated. I chose the diesel for the ability to pull a travel trailer easily and still get decent gas mileage. I don't know much about oil catch cans but my first thought is will it alter the warranty. It sounds like the catch can is basically catching the oil vapor and then letting it escape into the air??
Thanks again.
Mike
A good catch can will allow the oil vapour from the crank case to collect and then you will have to dump it out from time to time. But that will be oil that didn’t get burnt in the engine and cause ash loading in the DPF ...
The trick is to remove the OEM hose from the crankcase vent to the turbo and keep it in a safe place so you can reinstall it if warranty work is needed.
Buy new hose and install the oil catch can.

I bought my truck to haul my trailer also. And so far I am very impressed with the trucks ability to haul a double axle trailer with ease.
And the milage is extremely impressive when there is no trailer behind the truck.
Its unfortunate that diesels are being destroyed with poor quality sensors and DPFs that load up with ash and then stop working.
When it comes to developing vehicles that get great milage, diesels are way ahead of anything on the gasoline offering. I can’t imagine pulling my travel trailer with the gas engine.
I hate having an engine reving it’s guts out on every hill like the gassers do.
Diesels are the answer but we need much better DPFs. There has to be a way to let the ash out.

What I have noticed is owners that spend most of there time on the highway have almost no issues. It seems if your using the truck for a daily driver and stuck in traffic, spend time idling in traffic and don’t spend much time on the highway, you are at high risk for emissions issues....
I can take 2 different routes to work. One has a lot of highway running but is a longer route.
The other is mostly slow traffic but a shorter route.
I take the highway. I believe the truck will run trouble free longer even though the milage will be higher because of highway running over slow traffic...

Rob
 

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I was under the truck yesterday cause I was thinking of wrapping the pipe and maybe the DPF to keep the heat in. I'm not 100% sure what I'm looking at but it appears that the last round thing in the exhaust pipe system is the DPF, maybe located between the front and rear set area? Pretty far back. It seems the 5th injector is injecting directly into the exhaust pipe about 2-feet in front of what I think is the DPF? Although the pipe looks nice, the DPF must be coated steel because I find pits of rust starting. Is this correct what I'm looking at? Also explains why when it's raining I see very low DPF temperatures in comparison to exhaust EGT's. Might need to look at making a splash-pan to try to keep cold rain and snow from kicking up on the DPF. I just figure if things stay hot it's gotta be better. Thoughts?
I was thinking the same. (Rapping the DPF)
Then I thought maybe it would overheat when pulling the trailer.
If you look at GMs 3.0 inline 6. They have the DPF close to the engine to keep it hot. The less fuel you have to spray into the DPF to force a regen the better the trucks milage will be.
The bad part is that the tow limits on the 3.0 seem low compared to Fords and Rams 3.0
I believe this is to protect the DPF from over heating since it is so close to the exhaust manifold..
If the DPF overheats it will breakup inside. Just like a catalytic converter does when it overheats from a rich gas engine.
So I haven’t wrapped it.
Rob
 

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I came across this if anyone is interested in cleaning there own dpf
its a bit long but the guy is trying to prove he is doing it the best way possible with the best results
 

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So the DPF is actually nicely bookended with flanges and gaskets IIRC. Removal to get to it and pressure wash it is possible. I'll have to see what these self flushing videos look like.
I was under there and although it appears to have a flange just before the injector/pipe, DPF, the back of the DPF looks to be welded to the pipe that goes up and over the rear.
 

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I was under there and although it appears to have a flange just before the injector/pipe, DPF, the back of the DPF looks to be welded to the pipe that goes up and over the rear.
ihave to take another look at mine but I thought the DPF was before the SCR.
The DPF has small lines at each end that go to the pressure differential sensors.
There is a diesel injector before the DPF and a DEF injector before the SCR
I thought the SCR was just befor the tail pipe..

Rob
 

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ihave to take another look at mine but I thought the DPF was before the SCR.
The DPF has small lines at each end that go to the pressure differential sensors.
There is a diesel injector before the DPF and a DEF injector before the SCR
I thought the SCR was just befor the tail pipe..

Rob
It is definitely possible I'm looking at the wrong thing, I have a 2017. I "guessed" at which is the DPF based on what I think is the 5th injector. It's the only thing I can find that appears to be connected to a fuel source and not just a wiring harness. What I'm thinking is the DPF is the last of the exhaust components. Maybe I need to look for a diagram or something.
 

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Just found another video full of good I formation
And it looks like header wrap may be our friend after all


Rob
 

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I VHT Ceramic painted my SRC and DPF this weekend. Not that I think the ceramic paint will do much to hold in heat (maybe a little) but mostly because while the SRC appeared perfect, the DPF has some surface rust. Had I been able to remove the DPF easily I would have applied Cerakote at my buddies powder coating place and that would have definitely held heat in. If they used stainless steel in the construction of the DPF then GM used an extremely low grade stainless that has enough iron to rust. Additionally, if I decide to wrap the DPF I wanted it coated. I may start by wrapping the inlet tubes to the SRC and DPF first so heat isn't lost thru the thin walled pipes. Although it says the Exhaust After Treatment System will detect high DPF EGT conditions and throttle things back or stop regeneration I think I'm going to hold off a little before wrapping the DPF. I would really need to test and monitor post DPF EGT's to make sure wrapping it doesn't melt it. I had also been thinking of wrapping the SRC but the operating range of the SRC to be effective is below like 650 so I'm not sure wrapping it will actually decrease it's efficiency and set a code.

I found a great service bulletin. Looks like it was to educate service technicians on the 2.8's engine and emissions system. It explains how the entire system functions and where everything is located. I do plan at some point to create a splash shield and cover the SRC and DPF because I've noticed significantly cooler DPF EGT's when it's raining so certainly no chance of any passive regeneration.


Enjoy,
Art.
 

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I VHT Ceramic painted my SRC and DPF this weekend. Not that I think the ceramic paint will do much to hold in heat (maybe a little) but mostly because while the SRC appeared perfect, the DPF has some surface rust. Had I been able to remove the DPF easily I would have applied Cerakote at my buddies powder coating place and that would have definitely held heat in. If they used stainless steel in the construction of the DPF then GM used an extremely low grade stainless that has enough iron to rust. Additionally, if I decide to wrap the DPF I wanted it coated. I may start by wrapping the inlet tubes to the SRC and DPF first so heat isn't lost thru the thin walled pipes. Although it says the Exhaust After Treatment System will detect high DPF EGT conditions and throttle things back or stop regeneration I think I'm going to hold off a little before wrapping the DPF. I would really need to test and monitor post DPF EGT's to make sure wrapping it doesn't melt it. I had also been thinking of wrapping the SRC but the operating range of the SRC to be effective is below like 650 so I'm not sure wrapping it will actually decrease it's efficiency and set a code.

I found a great service bulletin. Looks like it was to educate service technicians on the 2.8's engine and emissions system. It explains how the entire system functions and where everything is located. I do plan at some point to create a splash shield and cover the SRC and DPF because I've noticed significantly cooler DPF EGT's when it's raining so certainly no chance of any passive regeneration.


Enjoy,
Art.
Mine is rusty also. High heat and cheap stainless is showing here also.
I am going to wrap mine. I believe that will allow for a passive partial regen.
Although I believe that will only save a bit of fuel. Not actually increases DPF longevity.

Does anyone know of a good wrap that will survive wet and very hot conditions?

Rob
 

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Mine is rusty also. High heat and cheap stainless is showing here also.
I am going to wrap mine. I believe that will allow for a passive partial regen.
Although I believe that will only save a bit of fuel. Not actually increases DPF longevity.

Does anyone know of a good wrap that will survive wet and very hot conditions?

Rob
 
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