My car has been at the dealer for almost 1 month
07-23-2014, 11:09 AM
#1
Drifting
Thread Starter
My car has been at the dealer for almost 1 month
I'm not complaining, as this has been very difficult to pin down.
I was getting a clunk/bang from the rear just as I was coming to a stop, and when I started up from a stop. It wasn't anything to do with a down or upshift, as it was in first the whole time. So the dealer has been working closely with PNA to try to determine the cause. They've gone through many iterations of reprogramming/breaking in/relearning the PDK, to no avail. Finally yesterday they called and said they may have found the solution. They tried another set of rear wheels from another 991 and the problem went away. The theory is the rear tires are slightly different circumferences/diameters. Which is causing the PDK to get confused at that low speed.
So they've ordered me brand new rear tires (free of charge to me) and are installing them today. Hopefully that will put the problem to bed.
I can't say enough good things about my dealer (Porsche of South Shore in Freeport LI) and Norman the service manager as they really worked hard to figure this out.
Jeff
I was getting a clunk/bang from the rear just as I was coming to a stop, and when I started up from a stop. It wasn't anything to do with a down or upshift, as it was in first the whole time. So the dealer has been working closely with PNA to try to determine the cause. They've gone through many iterations of reprogramming/breaking in/relearning the PDK, to no avail. Finally yesterday they called and said they may have found the solution. They tried another set of rear wheels from another 991 and the problem went away. The theory is the rear tires are slightly different circumferences/diameters. Which is causing the PDK to get confused at that low speed.
So they've ordered me brand new rear tires (free of charge to me) and are installing them today. Hopefully that will put the problem to bed.
I can't say enough good things about my dealer (Porsche of South Shore in Freeport LI) and Norman the service manager as they really worked hard to figure this out.
Jeff
07-23-2014, 11:25 AM
#2
Nordschleife Master
Very interesting! Thanks for posting!
I don't think you should worry that someone will interpret your post as " complaining " ,it actually provides great input!
I believe I've read something similar about a 991 Turbo S,where a guy had a vibration. After having the car for a while and replacing the front differential,I believe the dealer finally traced it down to the front wheels/rims.
This goes to show what can happen if you go with a different size/offset on these new cars.
I don't think you should worry that someone will interpret your post as " complaining " ,it actually provides great input!
I believe I've read something similar about a 991 Turbo S,where a guy had a vibration. After having the car for a while and replacing the front differential,I believe the dealer finally traced it down to the front wheels/rims.
This goes to show what can happen if you go with a different size/offset on these new cars.
07-23-2014, 12:00 PM
#3
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Wow! 3/16 of an inch can make that much of a difference? Why not more widespread? Glad you got a set a free shoes!!
07-23-2014, 12:25 PM
#4
Three Wheelin'
I have heard of some cars (4x4 - not Porsche) that end up with broken gearbox &/or differential just for mixing up radials with other type of tyres.
Last edited by Mondrian; 07-23-2014 at 12:59 PM.
07-23-2014, 01:01 PM
#5
Rennlist Member
I hope everything works out for you. Please update after you break in the tires.
Sometimes a clunk comes from the brake shoes letting go after being stuck to the surface of the rotor on initial take off after sitting/parking etc. especially when you park the car after driving in the rain.
Do you use the parking brake?
Sometimes a clunk comes from the brake shoes letting go after being stuck to the surface of the rotor on initial take off after sitting/parking etc. especially when you park the car after driving in the rain.
Do you use the parking brake?
07-23-2014, 01:08 PM
#6
Race Director
^ but the driver would have noticed a serious drag on the car.
thats interesting about the tires diameters. I think the system can handle a difference of up to 3/32?
thats interesting about the tires diameters. I think the system can handle a difference of up to 3/32?
07-23-2014, 01:13 PM
#7
Rennlist Member
Not a drag feeling but a "POP" feeling when they come off the rotor as soon as the car moves.
At the speed our rotors rust I sometimes get it after washing the car with the e-brake set.
I know the dealer probably tried every possible scenario from a loose brake rotor, axle bolt, control arm bushings, motor mounts, tranny mounts....... so much back there that could be giving a car a thump/clang/pop on take off.
At the speed our rotors rust I sometimes get it after washing the car with the e-brake set.
I know the dealer probably tried every possible scenario from a loose brake rotor, axle bolt, control arm bushings, motor mounts, tranny mounts....... so much back there that could be giving a car a thump/clang/pop on take off.
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07-23-2014, 02:59 PM
#8
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Yes good on you for reporting this to us. This is what this forum is all about. Complaining? Hardly. Sharing information with your fellow enthusiast which enriches us all. Now if this happens to someone else then they have a place to go to research. Complaining? NO you have become a resource to the rest of us.
07-23-2014, 11:42 PM
#10
Drifting
Thread Starter
Service manager called today. They put new tires on, didn't fix the problem.
They're having a senior tech from Atlanta come up to look at it next. TBD.
Re: "brake shoes letting go after being stuck to the surface of the rotor on initial take off after sitting/parking etc. especially when you park the car after driving in the rain"
This happens constantly. Picture driving in a parade (at that speed) each time I slow to just before a stop, clunk. Then if I speed back up, clunk again. Over and over.
I'll report back here what the tech from Atlanta finds.
They're having a senior tech from Atlanta come up to look at it next. TBD.
Re: "brake shoes letting go after being stuck to the surface of the rotor on initial take off after sitting/parking etc. especially when you park the car after driving in the rain"
This happens constantly. Picture driving in a parade (at that speed) each time I slow to just before a stop, clunk. Then if I speed back up, clunk again. Over and over.
I'll report back here what the tech from Atlanta finds.
07-24-2014, 01:41 AM
#11
Rennlist Member
Sounds more like an issue with the "hold" automatic parking brake on an incline is at fault. Dammit, I can't remember what forum I was reading but a guy with a 991 was complaining about the same issue with a PDK and that was it.
07-24-2014, 07:37 PM
#12
Drifting
Thread Starter
OK the new tires didn't fix the problem.
They had the senior tech from Atlanta there today, he troubleshot the problem all morning. He finally tried unplugging the PTV controller and the problem went away. So they are ordering me a new PTV controller.
They had the senior tech from Atlanta there today, he troubleshot the problem all morning. He finally tried unplugging the PTV controller and the problem went away. So they are ordering me a new PTV controller.
