EGR issues, observations, and musings

N

Noahtjensen

Active member
I'm looking specifically for conversation and comments from @lindenengineering @Ivan Borisovich @Midwestdrifter @OnlyVanz and anyone else who isn't going to just respond with "delete" or "The last time I had any issue with EGR was 25 ya on Chevy engine"

I'm driving a 2022 sprinter 3.0 4x4. I'm at 27,000 miles. I've had the following EGR issues with it.
  • The EGR has been cleaned 6-7 times triggered by drivability issues.
  • EGR cooler was replaced at ~22,000 because it was so clogged.
  • EGR valve "failed" at ~25,000 stuck closed and put me in a non-indicated limp mode
Observations
Based on conversations with the local sprinter dealer, it IS an issue that Mercedes "acknowledges" but has no permanent fix. Some speculation around driving conditions impact EGR clogging, I've seen speculations around weight, engine load, Italian tune-up etc...

Here's what I understand. EGR systems are designed to lower combustion temps to reduce NOX. Low combustion temps in diesels are sootier. So it seems like a self-destructive system. EGR lowers combustion temp, sootier exhaust feeds EGR and EGR cooler causing clogging. The DPF filter catches the soot caused by low combustion temps, not always caused by the EGR but also low load situations, idling, etc.

DPF regeneration is achieved by boosting exhaust temps to heat the DPF and burn soot. It seems like the Sprinter does this by changing fuel injection timing and EGR parameters to super heat the exhaust stream.

My Personal Observations
I use a ScanGuage and have become obsessed with monitoring everything I can. I originally got it so I would know when the van was performing a regen. I can now identify the moment a regen starts. I have an audible alarm when DPF load reaches 98, I can then watch to see when the fuel injection timing changes to increase the exhaust temp, Then I'll see the DPF temp start to skyrocket and then it settles around 1100-1200 F for the regen process.

I also watch EGR A%. There is a very distinct pattern to when it opens and closes based on throttle input, engine load, etc... This is also how I knew the EGR failed I could see the EGR A% was stuck at ~5% even under full load the EGR temp sensor was also staying quite cold. Normally my EGR temps are around ~180-220 F.

Musings and Theory
The last few regens I started observing what the EGR does during a regen and noticed something different with the EGR A%, EGR temp, and their relationship to driving conditions. Today I reached full DPF load on the highway and I think I figured out the behavior change. When a regen is active the EGR will OPEN while coasting (0% throttle coasting not just easing up on throttle) and EGR temps jump to as much as 300 F, this is opposite to the behavior I see when a regen is not active. Then the EGR will CLOSE under throttle, not even full throttle but anything other than coasting. Also opposite "normal". At idle though t a stop it does CLOSE both during and not during a regen.

So essentially when driving normally not during a regen, the EGR system is getting a full dose of "cold" "sooty" exhaust. It's actively working to keep combustion temps low to reduce NOX. And low combustion temps mean low exhaust temps with more soot. Then during a regen, if cruising at a steady load without significant coasting, all that super hot exhaust gas for the regen process is not flowing through the EGR system during the entire regen process. But, if during a regen, there is coasting, the super hot exhaust stream does flow through the EGR and possibly "cleans" it.

Are my EGR issues related to how I drive during a regen? I try to "time" my regens to happen while I'm on the highway and I'm probably never fully coasting, is that possibly negatively influencing EGR cleanliness?
 
W

Wrinkledpants

2017 144WB 4x4
Noahtjensen said:
I'm looking specifically for conversation and comments from @lindenengineering @Ivan Borisovich @Midwestdrifter @OnlyVanz and anyone else who isn't going to just respond with "delete" or "The last time I had any issue with EGR was 25 ya on Chevy engine"

I'm driving a 2022 sprinter 3.0 4x4. I'm at 27,000 miles. I've had the following EGR issues with it.
  • The EGR has been cleaned 6-7 times triggered by drivability issues.
  • EGR cooler was replaced at ~22,000 because it was so clogged.
  • EGR valve "failed" at ~25,000 stuck closed and put me in a non-indicated limp mode
Observations
Based on conversations with the local sprinter dealer, it IS an issue that Mercedes "acknowledges" but has no permanent fix. Some speculation around driving conditions impact EGR clogging, I've seen speculations around weight, engine load, Italian tune-up etc...

Here's what I understand. EGR systems are designed to lower combustion temps to reduce NOX. Low combustion temps in diesels are sootier. So it seems like a self-destructive system. EGR lowers combustion temp, sootier exhaust feeds EGR and EGR cooler causing clogging. The DPF filter catches the soot caused by low combustion temps, not always caused by the EGR but also low load situations, idling, etc.

DPF regeneration is achieved by boosting exhaust temps to heat the DPF and burn soot. It seems like the Sprinter does this by changing fuel injection timing and EGR parameters to super heat the exhaust stream.

My Personal Observations
I use a ScanGuage and have become obsessed with monitoring everything I can. I originally got it so I would know when the van was performing a regen. I can now identify the moment a regen starts. I have an audible alarm when DPF load reaches 98, I can then watch to see when the fuel injection timing changes to increase the exhaust temp, Then I'll see the DPF temp start to skyrocket and then it settles around 1100-1200 F for the regen process.

I also watch EGR A%. There is a very distinct pattern to when it opens and closes based on throttle input, engine load, etc... This is also how I knew the EGR failed I could see the EGR A% was stuck at ~5% even under full load the EGR temp sensor was also staying quite cold. Normally my EGR temps are around ~180-220 F.

Musings and Theory
The last few regens I started observing what the EGR does during a regen and noticed something different with the EGR A%, EGR temp, and their relationship to driving conditions. Today I reached full DPF load on the highway and I think I figured out the behavior change. When a regen is active the EGR will OPEN while coasting (0% throttle coasting not just easing up on throttle) and EGR temps jump to as much as 300 F, this is opposite to the behavior I see when a regen is not active. Then the EGR will CLOSE under throttle, not even full throttle but anything other than coasting. Also opposite "normal". At idle though t a stop it does CLOSE both during and not during a regen.

So essentially when driving normally not during a regen, the EGR system is getting a full dose of "cold" "sooty" exhaust. It's actively working to keep combustion temps low to reduce NOX. And low combustion temps mean low exhaust temps with more soot. Then during a regen, if cruising at a steady load without significant coasting, all that super hot exhaust gas for the regen process is not flowing through the EGR system during the entire regen process. But, if during a regen, there is coasting, the super hot exhaust stream does flow through the EGR and possibly "cleans" it.

Are my EGR issues related to how I drive during a regen? I try to "time" my regens to happen while I'm on the highway and I'm probably never fully coasting, is that possibly negatively influencing EGR cleanliness?
Click to expand...
Where do you live? How heavy are you? EGR threads are everywhere here, but I'll say your mileage between issues feels on the higher end, even compared to the normal "EGR" issue threads.

I've had our 2017 4x4 since new, and today at 140k. We were empty for about a year, and then fully built around 7500-8k lbs for half its life. At about 70k miles, we grew to about 9k lbs and have been full-time for the past 3 years. We're out west, so hills are everywhere, but we also fill up mostly with B20.

I cleaned our EGR once in this time. I do get the hiccup at 1700 rpm when I'm out east for long-stretches (like 3+ weeks), but works like a swiss watch out here in Tahoe.

Even when we were empty in Denver, I never had EGR problems. You're obviously aware of the "drive the fvck out of it" Italian tune up theory, but I'm wondering if there is something else driving these issues. I just can't imagine that much has changed on this motor with between the VS30 and NCV3 that I drive. Maybe MB did make the emissions run closer to the raged edge on the VS30, but I'm wondering if you have some other issue that may be far more challenging to diagnose.
 
Galactic-Stargazer

Galactic-Stargazer

Member
Noahtjensen said:
I'm looking specifically for conversation and comments from @lindenengineering @Ivan Borisovich @Midwestdrifter @OnlyVanz and anyone else who isn't going to just respond with "delete" or "The last time I had any issue with EGR was 25 ya on Chevy engine"

I'm driving a 2022 sprinter 3.0 4x4. I'm at 27,000 miles. I've had the following EGR issues with it.
  • The EGR has been cleaned 6-7 times triggered by drivability issues.
  • EGR cooler was replaced at ~22,000 because it was so clogged.
  • EGR valve "failed" at ~25,000 stuck closed and put me in a non-indicated limp mode
Observations
Based on conversations with the local sprinter dealer, it IS an issue that Mercedes "acknowledges" but has no permanent fix. Some speculation around driving conditions impact EGR clogging, I've seen speculations around weight, engine load, Italian tune-up etc...

Here's what I understand. EGR systems are designed to lower combustion temps to reduce NOX. Low combustion temps in diesels are sootier. So it seems like a self-destructive system. EGR lowers combustion temp, sootier exhaust feeds EGR and EGR cooler causing clogging. The DPF filter catches the soot caused by low combustion temps, not always caused by the EGR but also low load situations, idling, etc.

DPF regeneration is achieved by boosting exhaust temps to heat the DPF and burn soot. It seems like the Sprinter does this by changing fuel injection timing and EGR parameters to super heat the exhaust stream.

My Personal Observations
I use a ScanGuage and have become obsessed with monitoring everything I can. I originally got it so I would know when the van was performing a regen. I can now identify the moment a regen starts. I have an audible alarm when DPF load reaches 98, I can then watch to see when the fuel injection timing changes to increase the exhaust temp, Then I'll see the DPF temp start to skyrocket and then it settles around 1100-1200 F for the regen process.

I also watch EGR A%. There is a very distinct pattern to when it opens and closes based on throttle input, engine load, etc... This is also how I knew the EGR failed I could see the EGR A% was stuck at ~5% even under full load the EGR temp sensor was also staying quite cold. Normally my EGR temps are around ~180-220 F.

Musings and Theory
The last few regens I started observing what the EGR does during a regen and noticed something different with the EGR A%, EGR temp, and their relationship to driving conditions. Today I reached full DPF load on the highway and I think I figured out the behavior change. When a regen is active the EGR will OPEN while coasting (0% throttle coasting not just easing up on throttle) and EGR temps jump to as much as 300 F, this is opposite to the behavior I see when a regen is not active. Then the EGR will CLOSE under throttle, not even full throttle but anything other than coasting. Also opposite "normal". At idle though t a stop it does CLOSE both during and not during a regen.

So essentially when driving normally not during a regen, the EGR system is getting a full dose of "cold" "sooty" exhaust. It's actively working to keep combustion temps low to reduce NOX. And low combustion temps mean low exhaust temps with more soot. Then during a regen, if cruising at a steady load without significant coasting, all that super hot exhaust gas foE When the motor was completely cooled down the problem wasn't there. But once it heated back up it would start that chugging again. So to help it along
Click to expand...

Noahtjensen said:
I'm looking specifically for conversation and comments from @lindenengineering @Ivan Borisovich @Midwestdrifter @OnlyVanz and anyone else who isn't going to just respond with "delete" or "The last time I had any issue with EGR was 25 ya on Chevy engine"

I'm driving a 2022 sprinter 3.0 4x4. I'm at 27,000 miles. I've had the following EGR issues with it.
  • The EGR has been cleaned 6-7 times triggered by drivability issues.
  • EGR cooler was replaced at ~22,000 because it was so clogged.
  • EGR valve "failed" at ~25,000 stuck closed and put me in a non-indicated limp mode
Observations
Based on conversations with the local sprinter dealer, it IS an issue that Mercedes "acknowledges" but has no permanent fix. Some speculation around driving conditions impact EGR clogging, I've seen speculations around weight, engine load, Italian tune-up etc...

Here's what I understand. EGR systems are designed to lower combustion temps to reduce NOX. Low combustion temps in diesels are sootier. So it seems like a self-destructive system. EGR lowers combustion temp, sootier exhaust feeds EGR and EGR cooler causing clogging. The DPF filter catches the soot caused by low combustion temps, not always caused by the EGR but also low load situations, idling, etc.

DPF regeneration is achieved by boosting exhaust temps to heat the DPF and burn soot. It seems like the Sprinter does this by changing fuel injection timing and EGR parameters to super heat the exhaust stream.

My Personal Observations
I use a ScanGuage and have become obsessed with monitoring everything I can. I originally got it so I would know when the van was performing a regen. I can now identify the moment a regen starts. I have an audible alarm when DPF load reaches 98, I can then watch to see when the fuel injection timing changes to increase the exhaust temp, Then I'll see the DPF temp start to skyrocket and then it settles around 1100-1200 F for the regen process.

I also watch EGR A%. There is a very distinct pattern to when it opens and closes based on throttle input, engine load, etc... This is also how I knew the EGR failed I could see the EGR A% was stuck at ~5% even under full load the EGR temp sensor was also staying quite cold. Normally my EGR temps are around ~180-220 F.

Musings and Theory
The last few regens I started observing what the EGR does during a regen and noticed something different with the EGR A%, EGR temp, and their relationship to driving conditions. Today I reached full DPF load on the highway and I think I figured out the behavior change. When a regen is active the EGR will OPEN while coasting (0% throttle coasting not just easing up on throttle) and EGR temps jump to as much as 300 F, this is opposite to the behavior I see when a regen is not active. Then the EGR will CLOSE under throttle, not even full throttle but anything other than coasting. Also opposite "normal". At idle though t a stop it does CLOSE both during and not during a regen.

So essentially when driving normally not during a regen, the EGR system is getting a full dose of "cold" "sooty" exhaust. It's actively working to keep combustion temps low to reduce NOX. And low combustion temps mean low exhaust temps with more soot. Then during a regen, if cruising at a steady load without significant coasting, all that super hot exhaust gas for the regen process is not flowing through the EGR system during the entire regen process. But, if during a regen, there is coasting, the super hot exhaust stream does flow through the EGR and possibly "cleans" it.

Are my EGR issues related to how I drive during a regen? I try to "time" my regens to happen while I'm on the highway and I'm probably never fully coasting, is that possibly negatively influencing EGR cleanliness?
Click to expand...
I had a problem with the EGR not fully closing so I cleaned it. Then 3k miles later it started chugging up steep inclines again. I noticed it only did it when it was hot. So the next day, when it was completely cold, I disconnected wires to the EGR valve. It shifted gears at a much higher rpm and ran down the highway at higher rpm. I thought the engine running faster would negatively affect mpg but it didn't seem to.

I kept an eye on the DPF and it wouldn't go into regeneration mode even at 102%. So I pulled off the highway and turned it off and reconnected the wires to the EGR valve. It shifted just fine getting back onto the highway. The DPF went right into regeneration mode and the numbers dropped rapidly. In all the times I've watched the DPF regen I've never seen it do finish the cycle so rapidly.

I thought about disconnecting and reconnecting the wires again but decided against it for practical reasons. It would be a pain to keep stopping and doing this. In stead, now when I see a steep climb coming I manually downshift. My hope is that this keeps working until I can get to where I can clean the EGR valve again.
 
R

run4x4

2019 4x4 Crew
My van is 2019 and has 14k miles. It used to jerk climbing hills but on a recent trip it lost power on the freeway for like 10-15 seconds. Took it to an independent MB shop and they looked into with a scope and referred me to see the dealer for a remedy.

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