991.2 Carrera Cobb Tuning issue
#31
#32
I dropped the car off at AMS yesterday and they worked directly with Cobb. Right off the bat, after removing the bumper cover they found a vacuum leak near the water pump and they thought for sure that was the leak. They searched for other visible signs of leaks but nothing else was visible. They reinstalled the bumper, tuned to stage 1 91 map, datalogged, sent files to Cobb and the car is still acting the same. Issue is still there. Cobb took care of the cost for shop time but the issue still continues. AMS kindly said they do not have the time to continue working on my car with GTR World Cup coming up and they offered to make a new appointment after World Cup which is the first week of February. AMS believes there is still more vacuum leaks and they explained to me how hard it is to track down a leak that might be solenoid controlled so even a basic leak test will not find it. That’s about all the update I have unfortunately...
#35
#36
It seemed to be fixed with the new ECU, but you then had to remove it again to get it tuned.
Could you have disturbed something along that pathway?
#37
anything is possible I suppose! I will be taking the spoiler and bumper cover off to do some more visible checks but there isn’t really much in the way for ecu removal as far as vacuum lines go but I will be sure to check. I believe I will bring the car back to AMS in February but in the meantime I will be checking to see if I see any more obvious signs.
#38
anything is possible I suppose! I will be taking the spoiler and bumper cover off to do some more visible checks but there isn’t really much in the way for ecu removal as far as vacuum lines go but I will be sure to check. I believe I will bring the car back to AMS in February but in the meantime I will be checking to see if I see any more obvious signs.
#40
no smoke test but we have pressure tested and it holds quite well up to 20 psi. AMS thinks it could be a vacuum line that might be on the over side of a solenoid valve or one that will not show up with a air or smoke test due to electronics
#41
Why post a response like this? No one else is having issues like this. Besides having the satisfaction of tracking down the issue and resolving it, it potentially helps others who might encounter the same issue down the road.
#42
Sorry to hear you're still having this problem OP.
So just to be clear... In stock form your car is 100% but only on the tune it's having hiccups?
Try to flash the Stage 0 map (stock map replica from COBB) and take some data logs (by pushing the center button on the Accessport on the gauge screen). Then share them on here.
So just to be clear... In stock form your car is 100% but only on the tune it's having hiccups?
Try to flash the Stage 0 map (stock map replica from COBB) and take some data logs (by pushing the center button on the Accessport on the gauge screen). Then share them on here.
#43
Sorry to hear you're still having this problem OP.
So just to be clear... In stock form your car is 100% but only on the tune it's having hiccups?
Try to flash the Stage 0 map (stock map replica from COBB) and take some data logs (by pushing the center button on the Accessport on the gauge screen). Then share them on here.
So just to be clear... In stock form your car is 100% but only on the tune it's having hiccups?
Try to flash the Stage 0 map (stock map replica from COBB) and take some data logs (by pushing the center button on the Accessport on the gauge screen). Then share them on here.
car seems to run fine in stock form. It’s the higher boost that’s when it starts to drop off pressure. Once I datalog on stage 0 and stage 1, do you mean upload the excel file or is there a way to place it on a graph?
#44
The issue is the boost. The car is fine with stock OEM tune because it isnt putting much pressure on the system. With the tune (ANY TUNE) you are increasing the boost and other pressures and putting more strain on the lines.
Sounds like a really small leak which is why it will be so hard to find. Only under load will it manifest itself and with stock tune it wont be found because it isnt leaking under stock parameters.
So stop blaming Cobb who has thousands of tuned cars on the road without these issues. Clearly it isnt Cobbs fault yet they are coming out of pocket to help diagnose the leak. Top Notch Company IMO..
Sounds like a really small leak which is why it will be so hard to find. Only under load will it manifest itself and with stock tune it wont be found because it isnt leaking under stock parameters.
So stop blaming Cobb who has thousands of tuned cars on the road without these issues. Clearly it isnt Cobbs fault yet they are coming out of pocket to help diagnose the leak. Top Notch Company IMO..
#45
Check my post #122 for reference
https://rennlist.com/forums/991/1122...s-ready-9.html