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Sorry to resurrect an old thread but my attempts at completely solving this issue on my cayenne have failed so far. Have had this issue, although very intermittent, since I purchased my CS. Transfer case changed prior to my ownership and I’ve been doing 10k interval fluid flushes. Spark plugs changed at 35k (I know, a little late), and now brought to dealer for software update only to be told that the car has no faults, drives like the other CS they had on the lot, and already has the most recent DME software revision. Unlike what posters have said prior to the software update, I do have full boost when flooring the pedal down to pass from highway speed, but it’s at part throttle where the boost seems to drop.
Only thing I can think of is the tires are worn pretty low, but are evenly worn and correctly filled with air.
Has anyone else had similar mid throttle boost loss after the software update?
Not had it since update but will say what you are describing seems a lot like how my 2015 S was on it’s very first long(1200ish) mile road trip. That was almost 5 years ago and confidence in vehicle never returned so sadly just rent minivans ever since for road trips.
Resurrecting this thread as the GTS is still exhibiting the hesitation/loss of power intermittently on long trips in cooler weather. We just finished the 1700 mile drive to warmer weather. About 2/3 of the trip was in temperatures ranging from 20 deg to 45 deg. After a few hours throttle response was uneven with hesitation. At times difficult to maintain 75 to 80 mph on hills. Occurred in normal and sport mode. Wasn’t tied to cruse control. The turbo didn’t drop off like before the software patch but the display showed inconsistent boost. It would go to 3 to 5 psi than drop to zero. There would be no boost until I gave almost full throttle. Boost would be better for a while than back to inconsistent. A couple of hours the next day, after letting it sit overnight, the hesitation and inconsistent boost was back. Once the temps warmed into the 60s it ran great. No problems maintaining 80 and had great power for acceleration. Turbo boost is normal and quickly jumps to higher psi on acceleration. I’ve talked with the dealer several times but it’s perplexing where to start. I just purchased iCarscan hoping to be able to see something as the boast issue is occurring. It does seem similar to what BrendonSF mentioned in previous post. Are others experiencing anything similar?
This problem never came back for me after the software update.
One other thing I’m investigating as a secondary issue- is that I don’t have the major issue anymore, but on WOT or higher throttle/load I’m getting some dialing back again out of nowhere. Fresh plugs etc. I suspect my fuel pump. No codes but it’s a two pump system, and under more load and more fuel both pumps go on the same time. When one isn’t working as well- higher load, not as much fuel. On the old 955/957, you could pull a fuse and a single pump would deliver all the fuel and prevent this odd occurrence when both pumps are on and one of them isn’t 100% functional. I suspect that is why only at WOT or more load the ECU has to adjust due to the fuel delivery being off.
I had low fuel pressure scenario on mine a few months back. It actually is the only problem I have had that actually triggered a check engine light. Seems a little too common for the pumps to need to be replaced around every 50k miles.
Ok- as an update on the various things that can cause the issue even after getting the reflash from the dealership. AOS or crankcase vent system. At 67k miles, I was losing boost again going up hills etc. I ordered new crankcase vent systems for both sides for around $215 with new o-rings. Super simple to remove and replace. After tearing apart the original one, I found a tear in the rubber diaphragm inside, which would lead to a boost leak. The other side was not torn, however the rubber diagphragm was not in the best shape, and was probably close to tearing. No boost leak issues now, and since this is not connected to any sensors, its likely these lousy systems could be making the boost issue that we see up hills etc. For $215 and quick DIY bit of work (10min?) its worth the piece of mind.
Ok- as an update on the various things that can cause the issue even after getting the reflash from the dealership. AOS or crankcase vent system. At 67k miles, I was losing boost again going up hills etc. I ordered new crankcase vent systems for both sides for around $215 with new o-rings. Super simple to remove and replace. After tearing apart the original one, I found a tear in the rubber diaphragm inside, which would lead to a boost leak. The other side was not torn, however the rubber diagphragm was not in the best shape, and was probably close to tearing. No boost leak issues now, and since this is not connected to any sensors, its likely these lousy systems could be making the boost issue that we see up hills etc. For $215 and quick DIY bit of work (10min?) its worth the piece of mind.
I kept reading how the older turbo models had this issue with the AOS and people would swap the rubber diaphragm via some russian ebay seller. From the pressurized side, turbo outlet to intercooler is fine and all the way to the throttle body. I thought I was losing boost via diverters, and I replaced them with forge DVs. Got the boost holding a bit more, but then still noticed losing boost up a hill under load. This crankcase valve is connected to the throttle body so when it leaks due to a broken rubber diaphragm, bam, pressure shoots out as a boost leak, goes out to the intake box, but basically bleeds boost. Turbo models talked about a slight whistle with torn AOS. Honestly I didn’t hear it but recently with windows down and listening carefully under load I could hear something slight.
Not sure if this is case for other people, but the part is worn at 60k. See the crack in the rubber and how oil has deformed and stained it as well. Other side had no tiny crack but was very brown and inflexible.
I kept reading how the older turbo models had this issue with the AOS and people would swap the rubber diaphragm via some russian ebay seller. From the pressurized side, turbo outlet to intercooler is fine and all the way to the throttle body. I thought I was losing boost via diverters, and I replaced them with forge DVs. Got the boost holding a bit more, but then still noticed losing boost up a hill under load. This crankcase valve is connected to the throttle body so when it leaks due to a broken rubber diaphragm, bam, pressure shoots out as a boost leak, goes out to the intake box, but basically bleeds boost. Turbo models talked about a slight whistle with torn AOS. Honestly I didn’t hear it but recently with windows down and listening carefully under load I could hear something slight.
Not sure if this is case for other people, but the part is worn at 60k. See the crack in the rubber and how oil has deformed and stained it as well. Other side had no tiny crack but was very brown and inflexible.
Thanks for the images, I am at 53-54k miles so guess this will be something for me to look at next oil change if I notice an issue resurfacing by then. I have noticed lately the driver's side of my engine sure seems to have a loud ticking sound when cold. Do not remember that "feature" from before but maybe just become paranoid. I know the engine always has had the sound just after an oil change when waiting for it to warm back up and reset the computer service indicator. I been lucky and not had the boost issue revisit me in years now. Been unlucky and had the low fuel pressure detected issue happen twice in past 8-10 months, first time was still under extended warranty and got new fuel pumps then the second time out of warranty put it on a scanner and saw pressure within spec so reset the light and yet to revisit me but just waiting for it to manifest into some bigger problem.
Just got the SW update on my 2017 Cayenne S. Night and day difference. I noticed it immediately when I left the dealer. The car now drives like it is supposed to. There used to be a really bad RPM drop from 2nd-3rd and 3rd-4th where the engine just lugging and you could not keep a linear acceleration. After the SW update, that problem disappeared. RPMs still drop, but you now get proper engine timing and turbo boost so that you get normal acceleration. Haven't tried the cruise control on long distances yet, but I'm guessing that was fixed as well.
Just got the SW update on my 2017 Cayenne S. Night and day difference. I noticed it immediately when I left the dealer. The car now drives like it is supposed to. There used to be a really bad RPM drop from 2nd-3rd and 3rd-4th where the engine just lugging and you could not keep a linear acceleration. After the SW update, that problem disappeared. RPMs still drop, but you now get proper engine timing and turbo boost so that you get normal acceleration. Haven't tried the cruise control on long distances yet, but I'm guessing that was fixed as well.
Another thing you might notice is better fuel economy. I track all my fillips and the improved drive ability after the software update made a pretty significant improvement on economy. Actually it made the vehicle finally capable of getting what was rated by epa to get.
I kept reading how the older turbo models had this issue with the AOS and people would swap the rubber diaphragm via some russian ebay seller. From the pressurized side, turbo outlet to intercooler is fine and all the way to the throttle body. I thought I was losing boost via diverters, and I replaced them with forge DVs. Got the boost holding a bit more, but then still noticed losing boost up a hill under load. This crankcase valve is connected to the throttle body so when it leaks due to a broken rubber diaphragm, bam, pressure shoots out as a boost leak, goes out to the intake box, but basically bleeds boost. Turbo models talked about a slight whistle with torn AOS. Honestly I didn’t hear it but recently with windows down and listening carefully under load I could hear something slight.
Not sure if this is case for other people, but the part is worn at 60k. See the crack in the rubber and how oil has deformed and stained it as well. Other side had no tiny crack but was very brown and inflexible.
Im at 71k on my 2015 CS. Maybe I ought to take a look just to be safe?
Another thing you might notice is better fuel economy. I track all my fillips and the improved drive ability after the software update made a pretty significant improvement on economy. Actually it made the vehicle finally capable of getting what was rated by epa to get.
When I've done my own tracking, the real MPG is about 15-20% below the MPG reported by the computer on both my 981 Boxster S and this car. Haven't looked since I flashed. This is my wife's car, so I'm not very diligent in tracking it.
01-10-2021, 01:43 PM
