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Discussion Starter #1
I found a bug in the DPF regen cycle.
I have the torque app and monitor my Soot level very closely.
On the last regen cycle I arrived home before the regen cycle had completed.
I backed into my parking spot and noticed that if I raised the rpm up just a bit I could hear a definite difference in the exhaust note.
The tach was at approx 900 rpm. The exhaust note changed and the DPF temp started to raise.
If I held the rpm at 900 the truck was doing a regen even though I was not moving.
This should not be able to happen unless your speed is at or above 30.

So I wonder if GM found this bug and the new ECM flash was designed to fix this.
I have not done the update.

Anyone out there with or without the latest GM ECM update. Witch was supposed to trip a check engine light if the truck was regenerating to often.
And you need the torque app to try this........
During a regen cycle,
Stop the truck
Leave it in gear
With one foot on the brake and the other on the go pedal raise the RPM just a bit and listen for a deep exhaust note and watch the DPF temp.
Does it raise the temp ?
Do you hear the exhaust change to a deep pitch?

This could be a good thing.....

Rob
 

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I still wonder if using exhaust wrap would be a good thing to do. Keep the heat in up to and including the DPF.
 

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Discussion Starter #3
I still wonder if using exhaust wrap would be a good thing to do. Keep the heat in up to and including the DPF.
I think I read about you mentioning that before.
Just after that I came across some info that suggests Wrapping would be a good thing.
I been looking at some of the people in Europe that are cleaning there own DPFs.
And i noticed the outside edges of the DPF were clogged. Some of the passages in the middle were clear.
Got me thinking if it was cold out or raining only the centre of the DPF would be hot enough to burn the Soot out.

My only issue would be if the DPF gets to hot it will break up and become clogged.
But in a cold climate wrapping the DPF might be a really good idea.

Rob
 

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Yes I did mention is before, I also thought about the overheat possibility but figured the sensors on the exhaust system would handle that. I never even thought about the center being at temp but the exterior being to cool to properly do it's thing properly....that's a good catch!
 

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Discussion Starter #5
Yes I did mention is before, I also thought about the overheat possibility but figured the sensors on the exhaust system would handle that. I never even thought about the center being at temp but the exterior being to cool to properly do it's thing properly....that's a good catch!
I believe that's why the new 3.0 litre diesel has the DPF very close to the exhaust manifold.
But I also think that is why they have a lower tow rate than the compitition
Towing a heavy load may over heat the DPF.

Last summer I was towing my travel trailer and a regen had started just before I turned onto the highway.
With 6000lbs behind the truck the DPF was over 1000 F
I believe the ECM was spraying fuel into the exhaust stream even though the heavy load on the truck was already driving the exhaust temps up.
I don't think I would want wrap on the DPF that day.
But I am thinking it would be a good idea for the winter....
I think I will do it.

Rob
 

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I found a bug in the DPF regen cycle.
I have the torque app and monitor my Soot level very closely.
On the last regen cycle I arrived home before the regen cycle had completed.
I backed into my parking spot and noticed that if I raised the rpm up just a bit I could hear a definite difference in the exhaust note.
The tach was at approx 900 rpm. The exhaust note changed and the DPF temp started to raise.
If I held the rpm at 900 the truck was doing a regen even though I was not moving.
This should not be able to happen unless your speed is at or above 30.

So I wonder if GM found this bug and the new ECM flash was designed to fix this.
I have not done the update.

Anyone out there with or without the latest GM ECM update. Witch was supposed to trip a check engine light if the truck was regenerating to often.
And you need the torque app to try this........
During a regen cycle,
Stop the truck
Leave it in gear
With one foot on the brake and the other on the go pedal raise the RPM just a bit and listen for a deep exhaust note and watch the DPF temp.
Does it raise the temp ?
Do you hear the exhaust change to a deep pitch?

This could be a good thing.....

Rob
So I have a 2019 Colorado with the 2.8l minimal I live in Canada and I am lost my truck regularly Regens at idle every 15ish minutes. That being said I don't get lights on the dash and the regen is a sequence of 3-4 sec shots maybe 2-3 times in a row but other then that I don't ever notice a regen and I am a equipment operator and I know what a regen sounds like..so am I missing something or is this normal?
 

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Discussion Starter #7
So I have a 2019 Colorado with the 2.8l minimal I live in Canada and I am lost my truck regularly Regens at idle every 15ish minutes. That being said I don't get lights on the dash and the regen is a sequence of 3-4 sec shots maybe 2-3 times in a row but other then that I don't ever notice a regen and I am a equipment operator and I know what a regen sounds like..so am I missing something or is this normal?
if it wasn’t for the app I run I really wouldn’t be able to tell my truck was doing a regen
Unless I got out and I could smell it.
you can’t really tell while driving
You really need to be monitoring the exhaust temp to know what is going on.
what makes you think it’s regening at idle?
Rob
 

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if it wasn’t for the app I run I really wouldn’t be able to tell my truck was doing a regen
Unless I got out and I could smell it.
you can’t really tell while driving
You really need to be monitoring the exhaust temp to know what is going on.
what makes you think it’s regening at idle?
Rob
I can tell its regen during idle the exhaust does 2-3 3 second burps where the exhaust gets significantly loader and when standing at the back of the truck near the exhaust the temperature of the exhaust rises significantly as well just until the burps are done
Other than that you can't tell
 

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I can tell its regen during idle the exhaust does 2-3 3 second burps where the exhaust gets significantly loader and when standing at the back of the truck near the exhaust the temperature of the exhaust rises significantly as well just until the burps are done
Other than that you can't tell
I'm pretty sure that's the DEF fluid getting sprayed, not a regen. Mine does the same exact thing. NOX emissions are supposedly higher during idling, hence the DEF spraying during idle occasionally. As the DEF's main purpose is to lower NOX.
 

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Discussion Starter #10
Yes I did mention is before, I also thought about the overheat possibility but figured the sensors on the exhaust system would handle that. I never even thought about the center being at temp but the exterior being to cool to properly do it's thing properly....that's a good catch!
Update for you
I wrapped the DPF and part of the pipe.
it actually burns soot out of the DPF just running down the highway.
The temp of the DPF on the highway runs around 600-750 . And I have seen it as high as 850-900 on long up hill runs while at wide open throttle.
On the back roads it doesn’t get hot enough to burn any soot and the soot level climbs as usual.
But once on the highway the soot level slowly drops.
I left for work with 70% soot level and approx an hr later running on the highway at 70 mph the soot level was around 40%.
I wrapped the DPF with header wrap then completely taped it with aluminum tape.
Not sure if I will be able to keep it wrapped up in the summer but for now it’s been a good idea for increasing the distance between regens.

Also I tried another crazy idea today.
I have been wondering if I restricted the amount of soot getting to the intake if the truck would counteract by using more def.
The idea is to reduce the amount of soot getting to the intake but not throw any codes.
So this is what I found out.
I added a washer with a small hole in the small flex pipe that connects to the intake. This would reduce the amount of soot flow by 75%
I drove around the block to see if there was any ill effects and what I noticed was the torque app showing the EGR valve running at max.
The NOX levels were very high. So I figured the EGR was trying to compensate by opening all the way to get more soot in to reduce combustion temps.
No check engine light so out on the highway. And what I noticed was higher EGTs and soot levels that fell off very fast. With in 10 min on the highway the soot level in the DPF went from 28 to 16 and the DPF temps never went above 825. So very impressive.
But the bad news is that the truck logged a pending code. The code was inadequate EGR flow..
I expected that considering the EGR WAS WIDE OPEN trying to lower EGTs.
Next a washer with a slightly bigger hole. See if I can get away with that.

Rob
 

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Discussion Starter #11
I found a bug in the DPF regen cycle.
I have the torque app and monitor my Soot level very closely.
On the last regen cycle I arrived home before the regen cycle had completed.
I backed into my parking spot and noticed that if I raised the rpm up just a bit I could hear a definite difference in the exhaust note.
The tach was at approx 900 rpm. The exhaust note changed and the DPF temp started to raise.
If I held the rpm at 900 the truck was doing a regen even though I was not moving.
This should not be able to happen unless your speed is at or above 30.

So I wonder if GM found this bug and the new ECM flash was designed to fix this.
I have not done the update.

Anyone out there with or without the latest GM ECM update. Witch was supposed to trip a check engine light if the truck was regenerating to often.
And you need the torque app to try this........
During a regen cycle,
Stop the truck
Leave it in gear
With one foot on the brake and the other on the go pedal raise the RPM just a bit and listen for a deep exhaust note and watch the DPF temp.
Does it raise the temp ?
Do you hear the exhaust change to a deep pitch?

This could be a good thing.....

Rob
A small update in this bug.
if your in regen and you put the truck in park then put it back in gear. It will not regen at 900 rpm.
only if you stop while in regen and keep the brake on while increasing the rpm slightly will it aggressively increase DPF temp.
if anyone is experimenting with this be careful as the DPF will get way too hot....
 

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Update for you
I wrapped the DPF and part of the pipe.
it actually burns soot out of the DPF just running down the highway.
The temp of the DPF on the highway runs around 600-750 . And I have seen it as high as 850-900 on long up hill runs while at wide open throttle.
On the back roads it doesn’t get hot enough to burn any soot and the soot level climbs as usual.
But once on the highway the soot level slowly drops.
I left for work with 70% soot level and approx an hr later running on the highway at 70 mph the soot level was around 40%.
I wrapped the DPF with header wrap then completely taped it with aluminum tape.
Not sure if I will be able to keep it wrapped up in the summer but for now it’s been a good idea for increasing the distance between regens.

Also I tried another crazy idea today.
I have been wondering if I restricted the amount of soot getting to the intake if the truck would counteract by using more def.
The idea is to reduce the amount of soot getting to the intake but not throw any codes.
So this is what I found out.
I added a washer with a small hole in the small flex pipe that connects to the intake. This would reduce the amount of soot flow by 75%
I drove around the block to see if there was any ill effects and what I noticed was the torque app showing the EGR valve running at max.
The NOX levels were very high. So I figured the EGR was trying to compensate by opening all the way to get more soot in to reduce combustion temps.
No check engine light so out on the highway. And what I noticed was higher EGTs and soot levels that fell off very fast. With in 10 min on the highway the soot level in the DPF went from 28 to 16 and the DPF temps never went above 825. So very impressive.
But the bad news is that the truck logged a pending code. The code was inadequate EGR flow..
I expected that considering the EGR WAS WIDE OPEN trying to lower EGTs.
Next a washer with a slightly bigger hole. See if I can get away with that.

Robdpf
I like the way you're going about this.
I just installed a Banks data Monster gauge and I also noticed a slowdown on the soot loading while at hwy speeds. My DPF sits at 1130 deg when it's doing a REGEN. Being in the hot environment I wonder if the DPF were wrapped if it would just slow down the amount of fuel injected to maintain the same temp to burn off the carbon. This would just save some time because of the wrap and some fuel and ultimately raise the MPG's a little bit. Typically when not towing my REGENS are around 700 miles between each session. When towing it drops down to around 300 miles. I'm still learing the gauge and all it can do for me but it's pretty cool.
 

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Discussion Starter #13
I like the way you're going about this.
I just installed a Banks data Monster gauge and I also noticed a slowdown on the soot loading while at hwy speeds. My DPF sits at 1130 deg when it's doing a REGEN. Being in the hot environment I wonder if the DPF were wrapped if it would just slow down the amount of fuel injected to maintain the same temp to burn off the carbon. This would just save some time because of the wrap and some fuel and ultimately raise the MPG's a little bit. Typically when not towing my REGENS are around 700 miles between each session. When towing it drops down to around 300 miles. I'm still learing the gauge and all it can do for me but it's pretty cool.
Wow 700 miles between regens. That’s amazing.
It’s been really cold here and that means long warmups times. And with snow and traffic I’m at 250 miles between regens. I think the best I have done in the summer is 500 miles.
I think keeping the DPF warm is the key to better mileage as it will take a lot less fuel to get the DPF to incinerate the soot.
 

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Wow 700 miles between regens. That’s amazing.
It’s been really cold here and that means long warmups times. And with snow and traffic I’m at 250 miles between regens. I think the best I have done in the summer is 500 miles.
I think keeping the DPF warm is the key to better mileage as it will take a lot less fuel to get the DPF to incinerate the soot.
So this past weekend I was out for a 4 day get away from the house camping trip with 8 other couples. I tow a 2021 Keystone 258RKS and as I was towing along at about 65mph I snapped a few photos. I thought you would be interested in them so here you go!

20210205_103302.jpg



20210215_122056.jpg
20210215_121922.jpg


Each gauge will support 5 different pages and you can display whatever you want on each page. You can set the colors of each page, also set alerts to alert you on all kinds of things. The alerts set on non-displayed pages will still alert if you're not on that page. I have a pillar mount with two of these and that allows me to set 10 custom pages.

If you look at the bottom pic and the bottom two fields you can see last regen was 298 miles ago and, the prior regen was 660 miles ago with my current soot level holding at 14%. This is because of the exhaust temps being held high due to the tow load and a really strong headwind yesterday on the way home. The temp fields I have set up with the closest temp sensor to the exhaust manifold the 2dn one from that point down and so on. The 4th one is the DPF and that will hover at 1100+ during a regen. Most times it hangs around 1130 to 1150 degF for 18 minutes or so.

One of the fields I like is the GHP of fuel usage. It was hovering at 5.2 GPH and that gives you a pretty good feel for the possible range based on available fuel onboard.
 

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Discussion Starter #15
So this past weekend I was out for a 4 day get away from the house camping trip with 8 other couples. I tow a 2021 Keystone 258RKS and as I was towing along at about 65mph I snapped a few photos. I thought you would be interested in them so here you go!

View attachment 8993


View attachment 8990 View attachment 8991

Each gauge will support 5 different pages and you can display whatever you want on each page. You can set the colors of each page, also set alerts to alert you on all kinds of things. The alerts set on non-displayed pages will still alert if you're not on that page. I have a pillar mount with two of these and that allows me to set 10 custom pages.

If you look at the bottom pic and the bottom two fields you can see last regen was 298 miles ago and, the prior regen was 660 miles ago with my current soot level holding at 14%. This is because of the exhaust temps being held high due to the tow load and a really strong headwind yesterday on the way home. The temp fields I have set up with the closest temp sensor to the exhaust manifold the 2dn one from that point down and so on. The 4th one is the DPF and that will hover at 1100+ during a regen. Most times it hangs around 1130 to 1150 degF for 18 minutes or so.

One of the fields I like is the GHP of fuel usage. It was hovering at 5.2 GPH and that gives you a pretty good feel for the possible range based on available fuel onboard.
298 miles with a soot load of only 14%
DPF at over 800 deg will definitely burn the soot out.
I was looking at those Banks gauges. I am a fan of Gale Banks. His series on killing a Duramax was a real eye opener.
I learned a lot about fuel timing from that series.
Do you have anything done to your truck or is it all stock?
That is a Big looking trailer.
Its amazing what these tiny Diesel engines can do.
 

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298 miles with a soot load of only 14%
DPF at over 800 deg will definitely burn the soot out.
I was looking at those Banks gauges. I am a fan of Gale Banks. His series on killing a Duramax was a real eye opener.
I learned a lot about fuel timing from that series.
Do you have anything done to your truck or is it all stock?
That is a Big looking trailer.
Its amazing what these tiny Diesel engines can do.

Me too, I thought I was the only one watching his stuff. lol.. As a kid I had a "turbocharging a big block" book of his I must have read that thing 500 times over. I love his approach to everything he does, he's extremely methodical and that so works for me.

GDE for me prior to the shutdown. This is why my soot levels are so low and regen mileage is so high.

The trailer pulls real well, my buddy last weekend was in front of me on our way home from a 4 day get away from the house trip. It was windy as hell, he has a dodge 3500 dulley and a 42' 5th wheel Keystone Alpine. He was getting blown around almost exactly the same amount as I was. I considered this a good test on the stability side of things. We also had a 3rd couple, in front of me and the wife for a while with a 24' class "C" on a Ford chassis and that was getting blown around more then we were. As long as I keep it under 70, which I like to tow at around 62 to 65 mph it's a easy ride.
 

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Discussion Starter #17 (Edited)
Me too, I thought I was the only one watching his stuff. lol.. As a kid I had a "turbocharging a big block" book of his I must have read that thing 500 times over. I love his approach to everything he does, he's extremely methodical and that so works for me.

GDE for me prior to the shutdown. This is why my soot levels are so low and regen mileage is so high.

The trailer pulls real well, my buddy last weekend was in front of me on our way home from a 4 day get away from the house trip. It was windy as hell, he has a dodge 3500 dulley and a 42' 5th wheel Keystone Alpine. He was getting blown around almost exactly the same amount as I was. I considered this a good test on the stability side of things. We also had a 3rd couple, in front of me and the wife for a while with a 24' class "C" on a Ford chassis and that was getting blown around more then we were. As long as I keep it under 70, which I like to tow at around 62 to 65 mph it's a easy ride.
Watching Gale Banks videos on killing a Duramax, He was talking about how some tuners try and get more power by injecting fuel sooner and longer during the stroke. He was showing how you only have so many degrees of crank rotation to inject fuel.
If you try and extend that, fuel gets sprayed outside the bowl in the piston and you get a flame on top and against the cylinder walls and that damages the piston. He showed some damaged pistons from tuners that don’t understand that it’s safer to install bigger injectors instead of increasing injection duration. That kind of information really sticks in my head.
Good info. He really knows his diesels.
I have to keep my speed down 60-65 too. If not I find my trailer wags the truck a bit. I have two anti sway bars and a weight distribution hitch. My trailer is a toy hauler and the unloaded tongue wt is 700 lbs. I think that is crazy heavy but the tongue gets lighter with a toy in the trailer.

Rob
 

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Watching Gale Banks videos on killing a Duramax, He was talking about how some tuners try and get more power by injecting fuel sooner and longer during the stroke. He was showing how you only have so many degrees of crank rotation to inject fuel.
If you try and extend that, fuel gets sprayed outside the bowl in the piston and you get a flame on top and against the cylinder walls and that damages the piston. He showed some damaged pistons from tuners that don’t understand that it’s safer to install bigger injectors instead of increasing injection duration. That kind of information really sticks in my head.
Good info. He really knows his diesels.
I have to keep my speed down 60-65 too. If not I find my trailer wags the truck a bit. I have two anti sway bars and a weight distribution hitch. My trailer is a toy hauler and the unloaded tongue wt is 700 lbs. I think that is crazy heavy but the tongue gets lighter with a toy in the trailer.

Rob
That injection timing and duration was extremely interesting data, I watched a bunch of his stuff. I find him a wealth of information and generally he just seems to be such a down to earth guy and it makes watching and learning enjoyable.

I have an Anderson WDH and it works well for me. You have the benefit of the hauler to get your hitch weight right where you need it. For me I have to be careful because my pass-through storage is on the front of my trailer. It's easy for me to add too much tongue weight. I use a tongue scale and load some heavier items inside the rear of the trailer to offset the pass-through weight.

The things you learn !


Kevin
 
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