Diesel Cayenne and VW emission issue
10-20-2018, 06:11 PM
#5926
If you're near CT, try https://www.dpfregeneration.com . At least for exhaust and DPF issues, they attempt to clean out the soot VW/Audi/Porsche otherwise treat as $opportunity$. Not sure if already mentioned, or if there's anything they can do for EGR.
10-20-2018, 08:33 PM
#5927
This was about when I gave up. It was August, 2015, and I found myself burning 40-50 mile trips, with VagCom as my passenger. A month later, things changed.
I think CARB and "sniff" states are the same, where you can't "Malone" your way to NOx & particulate bliss unless you want to swap a compliant system back in every year??
If you're near CT, try https://www.dpfregeneration.com . At least for exhaust and DPF issues, they attempt to clean out the soot VW/Audi/Porsche otherwise treat as $opportunity$. Not sure if already mentioned, or if there's anything they can do for EGR.
I think CARB and "sniff" states are the same, where you can't "Malone" your way to NOx & particulate bliss unless you want to swap a compliant system back in every year??
If you're near CT, try https://www.dpfregeneration.com . At least for exhaust and DPF issues, they attempt to clean out the soot VW/Audi/Porsche otherwise treat as $opportunity$. Not sure if already mentioned, or if there's anything they can do for EGR.
10-21-2018, 08:24 PM
#5928
RL Community Team
Rennlist Member
Rennlist Member
Originally Posted by sclemmons
I have not had mine fixed yet. I don't need to fix it in my state. We have no inspection for emissions. Based on what I read, I fear I would just spend the money in a trade for a new car, when I am happy with the Cayenne Diesel I have.
Tell me again why I should have the fix done? The upside is money in the bank and a lot of hassle with my dealer 2 hours away. What is my downside if I do not?
Tell me again why I should have the fix done? The upside is money in the bank and a lot of hassle with my dealer 2 hours away. What is my downside if I do not?
10-21-2018, 08:25 PM
#5929
RL Community Team
Rennlist Member
Rennlist Member
Drove the CD a bit this weekend and noted that the lag is significantly reduced now that it's cooler here.
Interesting. Too bad I live in Texas.
Interesting. Too bad I live in Texas.
10-22-2018, 02:59 AM
#5930
Rennlist Member
I've noticed better performance in the '14 with the cooler weather, too. And the '15 wasn't as bad (about 1 - 1.5 sec vs 2 - 2.5 sec) when I took the tech out for a ride on Thursday, but still different; still a lack of response when you hit the gas. As in nothing... total dead spot. With the '14, at least, when you press the gas, you hear it start to work. The '15 just sits there, then all of a sudden decides, oh crap, he wants power!
Hoping to hear something tomorrow.
Hoping to hear something tomorrow.
10-22-2018, 10:41 AM
#5931
I've noticed better performance in the '14 with the cooler weather, too. And the '15 wasn't as bad (about 1 - 1.5 sec vs 2 - 2.5 sec) when I took the tech out for a ride on Thursday, but still different; still a lack of response when you hit the gas. As in nothing... total dead spot. With the '14, at least, when you press the gas, you hear it start to work. The '15 just sits there, then all of a sudden decides, oh crap, he wants power!
Hoping to hear something tomorrow.
Hoping to hear something tomorrow.
10-26-2018, 02:39 AM
#5932
Rennlist Member
Well, as expected, PCNA declared the hesitation/surge as "normal post fix behavior" for the 3rd service call for this. Their rational? Because it does it in every situation, it must be normal. Apparently, if it was only doing it on some occasions, it would indicate a problem.
I've been driving it a lot in manual mode the last couple of days and noticed something very interesting. With the shifter in manual mode, the TC doesn't come uncoupled and in nearly all roll on power situations, the vehicle responds almost pre-fix like. So now, when I approach a possible situation, I tip the shifter to M and let it downshift on its own. About the only time I've had poor response doing this is just before it's about to shift down to 2nd but is still in 3rd. Even so, the engine responds but it just takes a bit to get the torque to start moving it.
There is still a bit of a surge when the RPMs hit 2200 and I'm not sure what's causing that, but it's not the full slam power when the TC is locking up at that point.
Not done yet, but I guess I need to build some more data points. I am glad to know, however, I have a way to drive this safely and not worry about getting rear ended now.
I've been driving it a lot in manual mode the last couple of days and noticed something very interesting. With the shifter in manual mode, the TC doesn't come uncoupled and in nearly all roll on power situations, the vehicle responds almost pre-fix like. So now, when I approach a possible situation, I tip the shifter to M and let it downshift on its own. About the only time I've had poor response doing this is just before it's about to shift down to 2nd but is still in 3rd. Even so, the engine responds but it just takes a bit to get the torque to start moving it.
There is still a bit of a surge when the RPMs hit 2200 and I'm not sure what's causing that, but it's not the full slam power when the TC is locking up at that point.
Not done yet, but I guess I need to build some more data points. I am glad to know, however, I have a way to drive this safely and not worry about getting rear ended now.
10-26-2018, 04:43 AM
#5933
Moderator !x4
Good post
its reminiscent of an almost identical post of mine in 2004
the problem is/was the transmission mapping not being right for predictable conditions, like coming out of a sharp turn when it’s at least I cog to high and either manual change or heavy kickdown was required
on the TT i had, the problem did not appear due, I think, to the massive increase in available torque in control of the bodynweight
Dont expect this to be fixed, some “people” went the Lemon Route on this very dangerous subject with varying degrees of success
Shame i ever had that with my Pre-Fix Diesel
its reminiscent of an almost identical post of mine in 2004
the problem is/was the transmission mapping not being right for predictable conditions, like coming out of a sharp turn when it’s at least I cog to high and either manual change or heavy kickdown was required
on the TT i had, the problem did not appear due, I think, to the massive increase in available torque in control of the bodynweight
Dont expect this to be fixed, some “people” went the Lemon Route on this very dangerous subject with varying degrees of success
Shame i ever had that with my Pre-Fix Diesel
10-26-2018, 11:45 AM
#5934
Rennlist Member
Originally Posted by skiahh
I've been driving it a lot in manual mode the last couple of days and noticed something very interesting. With the shifter in manual mode, the TC doesn't come uncoupled and in nearly all roll on power situations, the vehicle responds almost pre-fix like. So now, when I approach a possible situation, I tip the shifter to M and let it downshift on its own. About the only time I've had poor response doing this is just before it's about to shift down to 2nd but is still in 3rd. Even so, the engine responds but it just takes a bit to get the torque to start moving it.
10-26-2018, 02:38 PM
#5937
RL Community Team
Rennlist Member
Rennlist Member
Also, I had my fix done in Jan / Feb and noticed no drivability issues until it started to warm up. So whatever the tuning is doing causing the issue, it doesn't need to do it in colder air. Any ECU programming experts care to hazard a guess? I don't know squat about the diesel combustion cycle and emissions to know why they would have programmed this huge lag when it's warm.
10-26-2018, 03:16 PM
#5938
Rennlist Member
That is what I experimented with before. When you pull on the downshift(button in '13-14 or paddle '15-16,) transmission automatically goes into manual and car is in a lower gear at higher RPM which helps drivability feel. Keep driving and it switches back to auto in 20 seconds or so. I never had to down shift more than 1 gear.
With the shifter in M and controlling gear selection with the lever or paddles, the TC appears to remain locked until you're almost at a stop, so when you apply throttle, you get a much more immediate response. Strangely, there is still a bit of a kick at 2200 RPM, though not really not that bad.
Warmer here, but still cool for the region (50's in the morning and 70's to 80's during the day) but I agree with you. Drove the CD last night and it felt 100% like pre-fix, except for the louder diesel clatter.
Also, I had my fix done in Jan / Feb and noticed no drivability issues until it started to warm up. So whatever the tuning is doing causing the issue, it doesn't need to do it in colder air. Any ECU programming experts care to hazard a guess? I don't know squat about the diesel combustion cycle and emissions to know why they would have programmed this huge lag when it's warm.
Also, I had my fix done in Jan / Feb and noticed no drivability issues until it started to warm up. So whatever the tuning is doing causing the issue, it doesn't need to do it in colder air. Any ECU programming experts care to hazard a guess? I don't know squat about the diesel combustion cycle and emissions to know why they would have programmed this huge lag when it's warm.
The fact that temps seem to have such a significant change to performance is definitely another driveability issue. I don't have another vehicle whose performance changes from winter to summer, nor have I ever driven one with significant differences like that, that I can recall (well, OK, I do... the other CD; but my Cummins diesel pickup certainly doesn't). With enough documented cases, that could spark a software change, I'd think, because we don't have consistent performance from the vehicles, making their response to driver inputs unknown and, thus unsafe.
Document, document, document! Go to your local dealers and get it entered into your vehicle records. And at some point, we might even need to do a safety complaint to the NHTSA. With enough, they'll have to open an investigation and force a response.
I still like the idea of suing CARB and EPA, but now, not for changing/ruining the vehicle's performance, but for approving an unsafe vehicle for operations on the roads.
10-26-2018, 05:42 PM
#5939
RL Community Team
Rennlist Member
Rennlist Member
I've tried this, too, and find that as long as the shift lever is in D, the software will keep doing its thing. Sure, you can override the gear selection temporarily, but even if I do that, the TC will still unlock when coasting or on the brakes. So even if I've pre-selected the right gear, the spool up of the transmission to get spinning and locked again makes the engine sit around doing practically nothing until the tranny is ready to accept the power. Which adds lag and brings us to magic number of 2200 RPM when it all locks up and off you go like a shot.
With the shifter in M and controlling gear selection with the lever or paddles, the TC appears to remain locked until you're almost at a stop, so when you apply throttle, you get a much more immediate response. Strangely, there is still a bit of a kick at 2200 RPM, though not really not that bad.
I'd guess it's simple physics. Warmer air is less dense than colder air. But the difference between 70-80 and 50 shouldn't be all that significant, especially with turbo charged engines. And if anything, the software should counter that, maybe keeping the wastegate closed longer with the warm air so it develops the full programmed boost. Unless at altitude, our turbos should be providing the same level of boost up to some altitude (say 8k' for arguments sake, because there aren't all that many roads above that altitude... but it could be higher or lower) so the cylinder air charge volume doesn't change until reaching that max altitude. I'm assuming our turbos have wastegates here... Something to dump pressure and prevent overboosting, anyway.
The fact that temps seem to have such a significant change to performance is definitely another driveability issue. I don't have another vehicle whose performance changes from winter to summer, nor have I ever driven one with significant differences like that, that I can recall (well, OK, I do... the other CD; but my Cummins diesel pickup certainly doesn't). With enough documented cases, that could spark a software change, I'd think, because we don't have consistent performance from the vehicles, making their response to driver inputs unknown and, thus unsafe.
Document, document, document! Go to your local dealers and get it entered into your vehicle records. And at some point, we might even need to do a safety complaint to the NHTSA. With enough, they'll have to open an investigation and force a response.
I still like the idea of suing CARB and EPA, but now, not for changing/ruining the vehicle's performance, but for approving an unsafe vehicle for operations on the roads.
With the shifter in M and controlling gear selection with the lever or paddles, the TC appears to remain locked until you're almost at a stop, so when you apply throttle, you get a much more immediate response. Strangely, there is still a bit of a kick at 2200 RPM, though not really not that bad.
I'd guess it's simple physics. Warmer air is less dense than colder air. But the difference between 70-80 and 50 shouldn't be all that significant, especially with turbo charged engines. And if anything, the software should counter that, maybe keeping the wastegate closed longer with the warm air so it develops the full programmed boost. Unless at altitude, our turbos should be providing the same level of boost up to some altitude (say 8k' for arguments sake, because there aren't all that many roads above that altitude... but it could be higher or lower) so the cylinder air charge volume doesn't change until reaching that max altitude. I'm assuming our turbos have wastegates here... Something to dump pressure and prevent overboosting, anyway.
The fact that temps seem to have such a significant change to performance is definitely another driveability issue. I don't have another vehicle whose performance changes from winter to summer, nor have I ever driven one with significant differences like that, that I can recall (well, OK, I do... the other CD; but my Cummins diesel pickup certainly doesn't). With enough documented cases, that could spark a software change, I'd think, because we don't have consistent performance from the vehicles, making their response to driver inputs unknown and, thus unsafe.
Document, document, document! Go to your local dealers and get it entered into your vehicle records. And at some point, we might even need to do a safety complaint to the NHTSA. With enough, they'll have to open an investigation and force a response.
I still like the idea of suing CARB and EPA, but now, not for changing/ruining the vehicle's performance, but for approving an unsafe vehicle for operations on the roads.
