2016-2017 Cayenne GTS Loss of Power
#31
Instructor
^Trying to interpret the above Triptronic manual shifting outcomes vs. auto, are you guys saying you need to downshift to coax boost and that only happens in manual paddle shifting modes? For further carification, are the above shifting experiences in negatively impacted GTS engines or properly functioning powerplants?
Not looking to create a food fight, really want to understand this. While this may be an obvious statement, IMO, todays trannys are more than capable performers in auto so the above Triptronic discussion leads me to believe that this is the potentially serious matter that the OT is based upon?
FWIW, I have yet to take my bride's new GTS out for a proper romping but this thread gives me the excuse to do so against her better wishes.
Thanks for the clarifications.
Not looking to create a food fight, really want to understand this. While this may be an obvious statement, IMO, todays trannys are more than capable performers in auto so the above Triptronic discussion leads me to believe that this is the potentially serious matter that the OT is based upon?
FWIW, I have yet to take my bride's new GTS out for a proper romping but this thread gives me the excuse to do so against her better wishes.
Thanks for the clarifications.
My vehicle has had no known issues since engine replacement 4-5k miles ago. So my assumption is that behavior is how it should be and his behavior of zero boost is not how it should be.
How that clarifies, kind of a pain replying on here via my iPhone and chrome so hard to read back and proof read to fix any mistakes on my part.
#32
Rennlist Member
Thank you for posting the video - definitely what I am seeing. I'll try to shoot one myself this weekend. This discussion thread will also help when the time comes to talk to my SA. Thankfully, the Service Department at my dealership of choice (Manager, Advisers, and Techs) seem to be up on the issues and have worked well with/for me in the past.
#33
Instructor
Thank you for posting the video - definitely what I am seeing. I'll try to shoot one myself this weekend. This discussion thread will also help when the time comes to talk to my SA. Thankfully, the Service Department at my dealership of choice (Manager, Advisers, and Techs) seem to be up on the issues and have worked well with/for me in the past.
#35
Guys, I have a 2016 GTS... I typically use manual mode for the Tiptronic, so I see the lack of boost situation in higher gears fairly often.
On the highway, at say 75-85 mph, if you go full throttle (but stopping prior to triggering the gear kickdown) in 7th or 8th gear, the boost will flash up to 4-5 lbs. for one second, then rapidly fall back to zero and stay there. As a general rule, if you are lugging the hell out of it in the higher gears, it will accelerate very, very slowly, with no boost - even under full throttle conditions.
If you go down to 6th gear, you will get some boost, but you don't see 10+ lbs until you get around 4,000 rpms.
Why does it do this? I figured Porsche wanted to keep boost off the engine in situations that are prone to induce detonation (i.e. pinging). So, instead of possibly running into detonation while under boost, it cuts boost until it's sure no detonation will occur (at higher rpms).
On the highway, at say 75-85 mph, if you go full throttle (but stopping prior to triggering the gear kickdown) in 7th or 8th gear, the boost will flash up to 4-5 lbs. for one second, then rapidly fall back to zero and stay there. As a general rule, if you are lugging the hell out of it in the higher gears, it will accelerate very, very slowly, with no boost - even under full throttle conditions.
If you go down to 6th gear, you will get some boost, but you don't see 10+ lbs until you get around 4,000 rpms.
Why does it do this? I figured Porsche wanted to keep boost off the engine in situations that are prone to induce detonation (i.e. pinging). So, instead of possibly running into detonation while under boost, it cuts boost until it's sure no detonation will occur (at higher rpms).
I just tried this a few times and mine does not accelerate by much but it quickly hits 0.5 BAR and keeps the boost there. To try this I got up to 75 mph then would either move the shift over(or paddle down one then up one) and downshift then upshift so in 8th and in manual mode then roll throttle down to just before the downshift spot.
- Car made about 7 lbs. of boost (about .5 bar) in 8th gear and boost level stayed there no matter how much I lugged it (i.e. even putting it in 8th at 45 mph). Boost probably would have went up as rpms creeped up if I has stayed on it.
- In 7th gear car made more like 9 lbs of boost at full throttle @ 75 mph (lugging it a bit), staying at 9 lbs. but going steadily up as the rpms creeped up.
This is odd as its completely different than my previous observations. I know that during my prior test, it was reading zero boost at WOT in the higher gears, which I thought was different than other turbo cars I've owned, hence my theory about detonation. I remember feathering the throttle which would get it to make a little boost, but once I went past say 10% throttle, boost would drop to zero and STAY there even with the throttle wide open.
So, there is something triggering low-boost situations in higher gears, but no one knows what it is....
EDIT: Further testing had been inconsistent. See my videos below. My car has bouts of both 'no-boost' and 'full boost' seemingly at random.
Last edited by cdog533; 02-27-2017 at 03:32 PM.
#36
Instructor
Based on your post, I tried lugging it in 7th and 8th gear @ 75 mph this morning - and got exactly YOUR results.
- Car made about 7 lbs. of boost (about .5 bar) in 8th gear and boost level stayed there no matter how much I lugged it (i.e. even putting it in 8th at 45 mph). Boost probably would have went up as rpms creeped up if I has stayed on it.
- In 7th gear car made more like 9 lbs of boost at full throttle @ 75 mph (lugging it a bit), staying at 9 lbs. but going steadily up as the rpms creeped up.
This is odd as its completely different than my previous observations. I know that during my prior test, it was reading zero boost at WOT in the higher gears, which I thought was different than other turbo cars I've owned, hence my theory about detonation. I remember feathering the throttle which would get it to make a little boost, but once I went past say 10% throttle, boost would drop to zero and STAY there even with the throttle wide open.
So, there is something triggering low-boost situations in higher gears, but no one knows what it is....
- Car made about 7 lbs. of boost (about .5 bar) in 8th gear and boost level stayed there no matter how much I lugged it (i.e. even putting it in 8th at 45 mph). Boost probably would have went up as rpms creeped up if I has stayed on it.
- In 7th gear car made more like 9 lbs of boost at full throttle @ 75 mph (lugging it a bit), staying at 9 lbs. but going steadily up as the rpms creeped up.
This is odd as its completely different than my previous observations. I know that during my prior test, it was reading zero boost at WOT in the higher gears, which I thought was different than other turbo cars I've owned, hence my theory about detonation. I remember feathering the throttle which would get it to make a little boost, but once I went past say 10% throttle, boost would drop to zero and STAY there even with the throttle wide open.
So, there is something triggering low-boost situations in higher gears, but no one knows what it is....
I could notice the wastegates backing everything out via exhaust tone and easiest for me to notice just at partial throttle. Every time I noticed it I usually blurted out some choice words about the car that included "the problem is happening again!". But my wife never could notice the sound difference, think I was noticing it because was struggling so much to find a details I could give the dealerships in hopes of them recognizing the vehicle had a problem. I think I put ~7k miles on mine over a few months with the problem happening, so I got way too intimate with the issue.
#37
Rennlist Member
It's one of those wonderful intermittent problems... I drove the GTS again this morning and found that it boosted "correctly" as well - no drop-off in boost as I observed a few days ago. Still running the same tank of fuel (no fill-ups since), so the change in response is not due to an actual (real) difference in fuel quality. It's one of those things where I'll have to always be ready to document the occurrence as it's not clear what triggers to vehicle to act in such a manner,
#38
Instructor
It's one of those wonderful intermittent problems... I drove the GTS again this morning and found that it boosted "correctly" as well - no drop-off in boost as I observed a few days ago. Still running the same tank of fuel (no fill-ups since), so the change in response is not due to an actual (real) difference in fuel quality. It's one of those things where I'll have to always be ready to document the occurrence as it's not clear what triggers to vehicle to act in such a manner,
#39
Engine replacement as a "solution". Somebody is confused. You know what else would be a "solution"? Entire car replacement.
Something, in the hundreds of parts that were replaced when the engine was swapped is not working correctly. I can't believe that anybody thought this was the way to diagnose something.
Sure, the problem is gone, but it wasn't fixed.
Something, in the hundreds of parts that were replaced when the engine was swapped is not working correctly. I can't believe that anybody thought this was the way to diagnose something.
Sure, the problem is gone, but it wasn't fixed.
#40
Instructor
Engine replacement as a "solution". Somebody is confused. You know what else would be a "solution"? Entire car replacement.
Something, in the hundreds of parts that were replaced when the engine was swapped is not working correctly. I can't believe that anybody thought this was the way to diagnose something.
Sure, the problem is gone, but it wasn't fixed.
Something, in the hundreds of parts that were replaced when the engine was swapped is not working correctly. I can't believe that anybody thought this was the way to diagnose something.
Sure, the problem is gone, but it wasn't fixed.
Here we are a year later since these problems started getting reported by owners and I am willing to bet Porsche still lacks a solution since August when they elected to replace my engine. I am sure that $15-20k cost was not one they want to just willingly eat if they have not been exhausting various diagnostic methods and other hopeful fixes.
#41
Pro
I've been keeping an eye on this thread as I'm only 1600Mi into my '16 Cayenne S. I've taken a few longer trips w/no issues.
FWIW, since we're all armchair quarterbacking, this sure sounds like a software thing and not a hardware thing.
Software will commonly pull boost when it detects a dangerous state. Could be engine temp, detonation, or even some sort of fault in the driveline. FWIW, it's also quite common for automatic equipped cars to pull timing and boost at shift time. I wonder if there's some sort of lag happening relating to shifts.
Regardless, I'm optimistic that it'll be solvable w/software.
FWIW, since we're all armchair quarterbacking, this sure sounds like a software thing and not a hardware thing.
Software will commonly pull boost when it detects a dangerous state. Could be engine temp, detonation, or even some sort of fault in the driveline. FWIW, it's also quite common for automatic equipped cars to pull timing and boost at shift time. I wonder if there's some sort of lag happening relating to shifts.
Regardless, I'm optimistic that it'll be solvable w/software.
#42
Instructor
i stumbled on an old email I sent to a friend back after I had an almost two hour meeting about my vehicle having this problem with the regional guy. It is a problem internal to some engines and at the time and I will assume still they do not know why some of the engines have that problem. They had already encountered it in a number of other vehicles with the issue and all started earlier that year. I am not sure how trying to relay what he said is arm chair quarterbacking but guess to each their own, was just trying to help prevent someone from going through the horrible experience I had to go through.
Perhaps software can somehow make an engine stop producing a sound that triggers the knock sensors, in my case one of four. But they have had a year at least to try and make that fix and if it is out no one is chiming in online about it.
Perhaps software can somehow make an engine stop producing a sound that triggers the knock sensors, in my case one of four. But they have had a year at least to try and make that fix and if it is out no one is chiming in online about it.
#43
Rennlist Member
Having worked with German companies for close to 20 years......with their culture...they might not be right, but they are never wrong and that is how they handle confrontation....just keep pushing for resolution like us Americans do in our culture!!
#44
Coming from an Audi family with 6+ of their vehicles over the years, this is not a typical approach, at least IME. Even for those of us with '16 GTS not experiencing these issues, this aint good.
Hopefully they get it squared away. Thanks for the input on this thread.
#45
Instructor
It happens to some 2015/2016 S and GTS Cayennes. I never could find an example of where the same engine(be it the bigger or smaller displacement) had it in the other models it is used in. I did see an instance in the Macan that seemed similar but they actually got a message on their display and Porsche resolved them pretty quickly via a software update.