[VtTD]

Hi folks,

I've complained about the regens of my car on here before but it's getting pretty annoying now. In the past when it would regen, I would definitely feel hesitation (really more a pulsating) when driving at low RPMs during regen (i.e. driving around 35-40mph.. it seems to put the transmission at a point where the RPMs are low and a lot of speed limits around here are around there so I'd sit at that speed for a while). I thought this hesitation was normal but in the past it seemed like nobody else was having it. I just kind of let it go. Now, I regen 3-4 times a tank. That alone is annoying but dealing with the hesitation on top of it is really annoying. I brought it to one dealer who said the emissions system seems to be working right. I spoke with GM and they are having me bring it to someone else this week. The second dealer does not seem too optimistic they will find anything because there are no error codes. Any ideas of where I can point the dealer? I'm pretty sure the first dealer just looked at the emissions system as opposed to maybe considering the emissions is fine but something else is wrong is that is causing more soot. One thing I have found a little weird is the pipe between the airbag and the turbo is damp on the outside. I would not call it wet, but it looks damp and you get the grime on your fingers when touch it.

Anyways, any ideas would be a huge help. 55k miles and I've already had two other emissions issues with this car. I really like the car, but I'm getting ready to ditch it if this doesn't get solved soon because I just need something more reliable. This latest issue has really going on since the Spring too.

 

[justin13703]

I also feel the pulsating at low rpms at certain times and I just kind of figured it was doing a regen and making it act funny. I also have a k&n intake and you can clearly hear a sound difference when it does it as well.

As far as emissions go, if I ever have an emissions issue when I'm out of warranty, I'll be getting the emissions delete setup and tune for it and forget about it.

 

[Tomko]

You need to think about what causes soot:

fuel

oil

air

Are you using quality fuel?

Are you using dexos2 oil at the 5w30 viscosity?

Has your oil filter been changed regularly?

Are you using the OEM air filter?

Have you checked that the air intake system is intact and without leaks? Checked the tightness of clamps?

 

[mr overkill]

Good luck. I'm on sensor 5 being ordered today and it's "normal" to this day I will sware it's from the "free "oilchanges

 

[diesel]

Hi folks,

I've complained about the regens of my car on here before but it's getting pretty annoying now. In the past when it would regen, I would definitely feel hesitation (really more a pulsating) when driving at low RPMs during regen (i.e. driving around 35-40mph.. it seems to put the transmission at a point where the RPMs are low and a lot of speed limits around here are around there so I'd sit at that speed for a while). I thought this hesitation was normal but in the past it seemed like nobody else was having it. I just kind of let it go. Now, I regen 3-4 times a tank. That alone is annoying but dealing with the hesitation on top of it is really annoying. I brought it to one dealer who said the emissions system seems to be working right. I spoke with GM and they are having me bring it to someone else this week. The second dealer does not seem too optimistic they will find anything because there are no error codes. Any ideas of where I can point the dealer? I'm pretty sure the first dealer just looked at the emissions system as opposed to maybe considering the emissions is fine but something else is wrong is that is causing more soot. One thing I have found a little weird is the pipe between the airbag and the turbo is damp on the outside. I would not call it wet, but it looks damp and you get the grime on your fingers when touch it.

Anyways, any ideas would be a huge help. 55k miles and I've already had two other emissions issues with this car. I really like the car, but I'm getting ready to ditch it if this doesn't get solved soon because I just need something more reliable. This latest issue has really going on since the Spring too.

To add to what others said, I would see if there's any way the dealership could hook up some sort of monitor and check all the parameters to see if anything is out of whack. Basic stuff like fuel pressures, sensor temperatures, boost pressure and so forth. Check the DPF pressure sensors - the regen is based off that. The sensors themselves may be giving false readings and showing more soot than it actually there. I've also heard that EGR valves sticking could cause the issue as well.

 

[oilburner]

Hi folks,

I've complained about the regens of my car on here before but it's getting pretty annoying now. In the past when it would regen, I would definitely feel hesitation (really more a pulsating) when driving at low RPMs during regen (i.e. driving around 35-40mph.. it seems to put the transmission at a point where the RPMs are low and a lot of speed limits around here are around there so I'd sit at that speed for a while). I thought this hesitation was normal but in the past it seemed like nobody else was having it. I just kind of let it go. Now, I regen 3-4 times a tank. That alone is annoying but dealing with the hesitation on top of it is really annoying. I brought it to one dealer who said the emissions system seems to be working right. I spoke with GM and they are having me bring it to someone else this week. The second dealer does not seem too optimistic they will find anything because there are no error codes. Any ideas of where I can point the dealer? I'm pretty sure the first dealer just looked at the emissions system as opposed to maybe considering the emissions is fine but something else is wrong is that is causing more soot. One thing I have found a little weird is the pipe between the airbag and the turbo is damp on the outside. I would not call it wet, but it looks damp and you get the grime on your fingers when touch it.

Anyways, any ideas would be a huge help. 55k miles and I've already had two other emissions issues with this car. I really like the car, but I'm getting ready to ditch it if this doesn't get solved soon because I just need something more reliable. This latest issue has really going on since the Spring too.

mostly city or highway driving?? the more city the more regens.

 

[VtTD]

Thanks for the tips. I'm good with keeping the mechanical stuff maintained, however I have the dealer do oil changes and I can only hope they use the right oil. I'm pretty sure they used Delvac once and I did not find out about it until it was down to about 10%. I think it's in the write up they did on the statement though, so I always have that if it becomes the cause of any issues. I think the first dealer watched the sensors pretty closely.. it sounded like. They didn't mention anything about the EGR valve so I'll definitely bring that up to the next dealer. I am doing mostly city now (I know, I know), but it does get on the open highway for a short time every day and I am out for long trips at least once every two weeks. Anyways, thanks again.. I'll keep you all posted.

 

[grs1961]

And remember that with a DPF regeneration it is not speed that matters, but heat, and the easiest way to get things hot is to use manual mode to hold the RPMs high.

 

[diesel]

And remember that with a DPF regeneration it is not speed that matters, but heat, and the easiest way to get things hot is to use manual mode to hold the RPMs high.

I do this when driving in slower areas and it works fine, but I do notice that the soot seems to come back faster than if I were just driving 70 MPH on a highway. Not an issue, just an observation.

 

[grs1961]

I do this when driving in slower areas and it works fine, but I do notice that the soot seems to come back faster than if I were just driving 70 MPH on a highway. Not an issue, just an observation.

Hmm, that behaviour seems quite possible, thinking about it.

I keep meaning to look if I can see soot levels with Torque Pro.

 

[DslGate]

Thanks for the tips. I'm good with keeping the mechanical stuff maintained, however I have the dealer do oil changes and I can only hope they use the right oil. I'm pretty sure they used Delvac once and I did not find out about it until it was down to about 10%. I think it's in the write up they did on the statement though, so I always have that if it becomes the cause of any issues. I think the first dealer watched the sensors pretty closely.. it sounded like. They didn't mention anything about the EGR valve so I'll definitely bring that up to the next dealer. I am doing mostly city now (I know, I know), but it does get on the open highway for a short time every day and I am out for long trips at least once every two weeks. Anyways, thanks again.. I'll keep you all posted.

Your problems sound identical to mine. Frequent regens and loss of fuel mileage. I am getting some regens at 50 mile intervals with 75% highway, 25 city or mixed. GM corporate denial and Chevy Customer Care nowhere to be found. Two check engine lights in two weeks. Less than 8K miles, but fortunately under b 2b warranty. Frustrating indeed.

i use top tier diesel with no bio ( P66 Brand )and have all service done at dealer.

Correction edit

 

[VtTD]

Ouch.. 25mpg. Seems to be an issue with these cars. If a bunch of us are having the problem and GM does nothing, maybe we work together to take action against them. I don't care if this is diesel or not. The last thing I expect to drop money into is an emissions system on a car.

Your problems sound identical to mine. Frequent regens and loss of fuel mileage. I am getting some regens at 50 mile intervals with 75% highway, 25 city or mixed. GM corporate denial and Chevy Customer Care nowhere to be found. Two check engine lights in two weeks. Less than 8K miles, but fortunately under b 2b warranty. Frustrating indeed.

i use top tier diesel with no ethanol ( P66 Brand )and have all service done at dealer.

 

[Tomko]

i use top tier diesel with no ethanol ( P66 Brand )and have all service done at dealer.

There is no such thing as top tier diesel.

Ethanol is is never a component of any kind of diesel.

 

[DslGate]

There is no such thing as top tier diesel.

Ethanol is is never a component of any kind of diesel.

Sorry, but I don't run bio diesel which to me is not top tier. You say roof, I say ruf, but I run non-BIo in my car in a state where bio is encouraged and actually used to 20% bio. Phillips 66 in my area has pure or "neat" diesel. Meaning 0 bio. The only diesel available here From Shell or BP is B20.

 

[LulzT1]

I have been meaning to post an update in the other frequent regen thread as I have been monitoring my regens, but I guess I'll just post here..

I too thought I was having abnormally short regen intervals. No CELs or errors I could see/scan. I use Mobile Super 3000 XE oil, AC Delco filter, replaced intake filter and fuel filter with OEM MANN, same SHELL diesel exclusively and all, still had regens between 60-150miles (up to 4 regens per tank) with 30k on the clock. I do 90% highway.

I now have 43k and just had my LONGEST regen intervals of 730 ( sunoco 5% bio blend) and 840 (SHELL / royal farms) miles on my trip to and from OBX (with 2 kayaks on the roof, 4 adults with luggage, avg'd 39mpg). I haven't changed anything on the car except new NOX sensor for P11D7 at 40k (which I think is irrelevant anyway). Aside from the road trip I have been averaging 200-300+ miles between regens since about 38k miles and just had my best commuting tank of 47.5mpg with 3 regens on it.

What I have changed is my driving habits and time I leave for work. In an effort to increase my fuel mileage, I slowed down from 75-80mph to 60-65mph which makes a huge difference (takes some adjusting though). I try to use cruise control as much as possible, too. I don't think acceleration makes much of a difference but I try not to punch it anyway to avoid dumping fuel in the motor. I also leave a half hour earlier for work to avoid traffic. Seems to have helped me, worth a shot.

I noticed slower / city driving kills my mileage and accumulates soot faster.. not much that can be done there. Keep in mind the car dumps excess fuel to heat up the dpf faster, you'll notice egts higher than 1000 within the first few miles of driving. So if you travel short distances and allow ample time for the car to cool, you'll be doing that pretty often without getting enough miles at a higher efficiency to average out a higher mpg.

Just some things I've been noting and will continue to monitor, take it for what it's worth. Overall the car is great despite a few CELs which were expected as a first gen diesel emissioms system. I think you'll drive yourself and the local dealers nuts trying to diagnose something that's probably normal. If you didn't have a SG you probably wouldn't think there was an issue to begin with IMO. Lastly, remember the epa figures are 27/33/46, so if you fall between those figures I'd say you're ok.

 

[VtTD]

Yeah I'm going to monitor it. It's weird that I never had this issue until this Spring. I brought it in today and this dealer didn't find anything except a fuel trim update. They admitted regens that often seems off so at least they see my point. We'll see if the fuel trim does anything. Assuming it doesn't.. I'm pretty confident there's something wrong so I'll keep bugging Chevy as long as it takes to get this resolved. I can be a giant PIA when I want to be . I am asking the dealers to note the lifetime regens everytime I bring it in to prove the regens are as frequent as they are. The 110 or so regens I've had over 55k miles does not sound too bad.. until you realize how many were in the past month or two.

I have been meaning to post an update in the other frequent regen thread as I have been monitoring my regens, but I guess I'll just post here..

I too thought I was having abnormally short regen intervals. No CELs or errors I could see/scan. I use Mobile Super 3000 XE oil, AC Delco filter, replaced intake filter and fuel filter with OEM MANN, same SHELL diesel exclusively and all, still had regens between 60-150miles (up to 4 regens per tank) with 30k on the clock. I do 90% highway.

I now have 43k and just had my LONGEST regen intervals of 730 ( sunoco 5% bio blend) and 840 (SHELL / royal farms) miles on my trip to and from OBX (with 2 kayaks on the roof, 4 adults with luggage, avg'd 39mpg). I haven't changed anything on the car except new NOX sensor for P11D7 at 40k (which I think is irrelevant anyway). Aside from the road trip I have been averaging 200-300+ miles between regens since about 38k miles and just had my best commuting tank of 47.5mpg with 3 regens on it.

What I have changed is my driving habits and time I leave for work. In an effort to increase my fuel mileage, I slowed down from 75-80mph to 60-65mph which makes a huge difference (takes some adjusting though). I try to use cruise control as much as possible, too. I don't think acceleration makes much of a difference but I try not to punch it anyway to avoid dumping fuel in the motor. I also leave a half hour earlier for work to avoid traffic. Seems to have helped me, worth a shot.

I noticed slower / city driving kills my mileage and accumulates soot faster.. not much that can be done there. Keep in mind the car dumps excess fuel to heat up the dpf faster, you'll notice egts higher than 1000 within the first few miles of driving. So if you travel short distances and allow ample time for the car to cool, you'll be doing that pretty often without getting enough miles at a higher efficiency to average out a higher mpg.

Just some things I've been noting and will continue to monitor, take it for what it's worth. Overall the car is great despite a few CELs which were expected as a first gen diesel emissioms system. I think you'll drive yourself and the local dealers nuts trying to diagnose something that's probably normal. If you didn't have a SG you probably wouldn't think there was an issue to begin with IMO. Lastly, remember the epa figures are 27/33/46, so if you fall between those figures I'd say you're ok.

 

[CruzeDan]

"I think you'll drive yourself and the local dealers nuts trying to diagnose something that's probably normal. If you didn't have a SG you probably wouldn't think there was an issue to begin with IMO"
Exactly

 

[VtTD]

Negative. I don't have a SG. The car drives rougher. And you can absolutely tell with the MPG read outs.

"I think you'll drive yourself and the local dealers nuts trying to diagnose something that's probably normal. If you didn't have a SG you probably wouldn't think there was an issue to begin with IMO"
Exactly

 

[DslGate]

You need to think about what causes soot:

Fuel. Check

oil. Check

air. Check

Are you using quality fuel? Check

Are you using dexos2 oil at the 5w30 viscosity? Check

Has your oil filter been changed regularly? Check

Are you using the OEM air filter?

Have you checked that the air intake system is intact and without leaks? Checked the tightness of clamps. Double check weekly ?

See answers above as I also suffer from very frequent regens on the CTD. I use neat diesel or non-bio and have double checked dealers oil change three weeks ago. Car only has 8000 miles and regens are very frequent.

 

[mr overkill]

HUM im gonna have to hook the scanner today and see what my lifetime regens are