991.2 C4s turbo problems. Has anyone had this happen??
#16
What I don't understand is why the car would show a code for supercharger malfunction when it was a faulty gasket in the fuel pump?
I should amend my previous comment. While I don't have any issues with the turbos (no messages or loss of power) the boost gauge rarely shows any boost. It used to show up to 12 psi in sport but now nothing. Maybe 4-5 psi but usually nothing. I haven't bothered with it because the car drives fine. At my next service in July, I will ask the dealer.
I should amend my previous comment. While I don't have any issues with the turbos (no messages or loss of power) the boost gauge rarely shows any boost. It used to show up to 12 psi in sport but now nothing. Maybe 4-5 psi but usually nothing. I haven't bothered with it because the car drives fine. At my next service in July, I will ask the dealer.
There are flaps on the intake runners of the supercharger intake manifold that have vacuum actuated solenoids that control them.
The flaps got stuck closed because there was insufficient vacuum to open them. With them closed there was not enough airflow so the manifold absolute pressure sensor responds with a boost target not reached.
The German techs found the vacuum leak issue by isolating the intake manifold flaps and since the supercharger had been on and off the car several times they happened to find a vacuum line that was compromised.
In the end however the true culprit was the fuel tank sending unit/fuel pump gasket.
#17
I am amazed that after buying 15 to 20 cars over 33 years, that this dealer doesnt stand on their head to get me a replacement part, especially after they destroyed the hoses when they removed the turbos. Let's say another few weeks goes by and no parts, the car is down for 6 weeks with no parts on the horizon. I am then in a tougher situation. Cannot get the car on the road and am still obligated to pay the lease. The dealer does nothing to solve a problem that they caused and I have to pay for it. The warranty is then useless
#18
Rennlist Member
A couple of things to consider:
The codes thrown and read by PIWIS are only as good as the embedded software code. That code is only as good as the imaginations of the Porsche employees/contractors/suppliers writing the software requirements. Humans are notoriously bad at prognosticating how failures will manifest. Teams of humans,. in my experience, as a matter of course, positively hate writing requirement and then code for logging errors. They like that less than writing test code. Thus, the codes read by PIWIS can be wild goose chases.
PCNA will only reimburse a dealer for warranty work if it is approved. How does work get approved? You guessed it: based upon PIWIS codes and fault trees. Only after the fault tree has be exhaustively covered are experienced 'authorized' brains allowed to consider the problem irrespective of 'the book.' And those 'authorized' brains are PCNA employees.
So, no matter how smart or motivated a Dealer Tech is, they can only do, under a warranty situation, what PCNA approves.
The codes thrown and read by PIWIS are only as good as the embedded software code. That code is only as good as the imaginations of the Porsche employees/contractors/suppliers writing the software requirements. Humans are notoriously bad at prognosticating how failures will manifest. Teams of humans,. in my experience, as a matter of course, positively hate writing requirement and then code for logging errors. They like that less than writing test code. Thus, the codes read by PIWIS can be wild goose chases.
PCNA will only reimburse a dealer for warranty work if it is approved. How does work get approved? You guessed it: based upon PIWIS codes and fault trees. Only after the fault tree has be exhaustively covered are experienced 'authorized' brains allowed to consider the problem irrespective of 'the book.' And those 'authorized' brains are PCNA employees.
So, no matter how smart or motivated a Dealer Tech is, they can only do, under a warranty situation, what PCNA approves.
#19
Rennlist Member
Because the vacuum system is tied into the evaporative emissions.
There are flaps on the intake runners of the supercharger intake manifold that have vacuum actuated solenoids that control them.
The flaps got stuck closed because there was insufficient vacuum to open them. With them closed there was not enough airflow so the manifold absolute pressure sensor responds with a boost target not reached.
The German techs found the vacuum leak issue by isolating the intake manifold flaps and since the supercharger had been on and off the car several times they happened to find a vacuum line that was compromised.
In the end however the true culprit was the fuel tank sending unit/fuel pump gasket.
There are flaps on the intake runners of the supercharger intake manifold that have vacuum actuated solenoids that control them.
The flaps got stuck closed because there was insufficient vacuum to open them. With them closed there was not enough airflow so the manifold absolute pressure sensor responds with a boost target not reached.
The German techs found the vacuum leak issue by isolating the intake manifold flaps and since the supercharger had been on and off the car several times they happened to find a vacuum line that was compromised.
In the end however the true culprit was the fuel tank sending unit/fuel pump gasket.
#20
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If diagnostic codes can lead to wild goose chases, what recourse does a technician have in diagnosing a problem correctly?
These guys are left in the dark.
Experience should help but these are new engines. Porsche must be training them otherwise how are they approved as certified Porsche dealers and technicians?
The *problem* with modern cars is that no amount of training and knowledge will illuminate what is happening inside the embedded software code in the various control units. A veritable $h1+-ton of functionality is controlled or modulated by the software. The requirements of the software are not part of the training.
A simple somewhat contrived example: On 'old school' Porsche's oil temperature is the result of purely mechanical and simple electrical systems. A problem with too-high oil temperature is diagnosable with knowledge, wiring diagrams, and simple tools. Whereas on this generation of Porsches, steady-state oil temperature can be 'changed' via the Sport/Sport+ buttons. These buttons are connected not by discrete wires but to a network. When pressed their signal on the network causes a control unit to do 'something.' But exactly what?
Furthermore, while a real-time diagnostic data gathering mode exists via the PIWIS laptop there is no training for what the resultant logs actually mean or how to interpret them.
Again a simple non-contrived example: One of the outputs in the log is 'throttle position' for each data sample in time. On an old-school Porsche there's a cable between the pedal and the actual throttle plate for the intake system. However, on modern cars, the pedal is connected 'by software' to the throttle plate. So, is the position in the log that which is commanded by the pedal? Or is it the throttle plate position commanded by the engine control unit? The techs don't know the answer to this question. And the answer to that question can be critical during diagnosis.
And finally, it seems this odd relationship between dealer and Porsche is screwing the customer.
It does not spell confidence at all.
Automotive engines and software is not my field so a customer like me can expect to get the runaround because I cannot diagnose the problem myself or have to pay for the dealer’s mistakes even when the car is under warranty?
Where it really gets ugly is when your Porsche is out of warranty. Then you pay sooner or later for mistakes others may make.
And that is why, I will add, I am busy accumulating knowledge and tools pertinent to the care and feeding of the modern Porsches. The key variable in this is when/if enough reverse engineering happens to be able to dispense with the PIWIS laptop (which is simply too expensive for any entity that doesn't use it almost every day. For financial mortals at least.) If it doesn't happen there will come a time when the only Porsches we own are 928s. Those are not a mystery to me.
Imagine this happening in the medical field in imaging or IVD or even therapeutics. Companies get screwed and can’t pass the buck to the patient because of the relationship between the device manufacturer and the hospital.
#21
Rennlist Member
I'm not quite sure I understand the above. I've been involved in software for the healthcare industry and my wife heads QA for a medical device company. With years of absorbing stories from her, my participation on the software side, and decades of experience as an 'end user' I have to say that my perspective is that making the healthcare sausage is far more ugly than the automotive repair sausage.
The hospital then calls the instrument manufacturer to complain that their expensive instrument is malfunctioning. The manufacturer says that the hospital must have broken it and they won’t take care it. Or they send an incompetent or untrained technician who can’t find any problems. Guess how long before they are out of business or sued?.If the hospital is a long term customer, would you want to lose the account? If the doctor, based on the original scan had sent the patient home and the patient got a second opinion that confirmed the original diagnosis, what would happen to the doctor or hospital? Can they blame the instrument manufacturer or the patient? Worse, what if the patient did not follow up after the initial misdiagnosis and died because the tumor metastasized and could not be treated? Then the hospital and doctor are liable for malpractice.
Car is just a car. Can't drive it. No big deal. But this situation with the dealer and Porsche is absurd. Makes me rethink my prospects of long term ownership of my 911 that I bought new.
Last edited by subwoofer; 06-15-2019 at 01:19 PM.
#22
Nordschleife Master
Why would Germany be "not willing to send the vacuum hoses?" That makes no sense whatsoever. It seems that they are not telling you the whole story or are just flat out lying to you.
#23
Rennlist Member
I am a 13 Porsche car owner over time and would be at wits end over this. Especially if I'm paying for a lease.
If the lease is through Porsche Financial I would call, write or have my lawyer write them a letter stating you are not paying the lease until Porsche and the dealer work out the issue. I always find stopping the flow of cash to be a good way to get attention.
This is a ridiculous situation your dealer should be taking care of and offering to compensate you financially.
If the lease is through Porsche Financial I would call, write or have my lawyer write them a letter stating you are not paying the lease until Porsche and the dealer work out the issue. I always find stopping the flow of cash to be a good way to get attention.
This is a ridiculous situation your dealer should be taking care of and offering to compensate you financially.
#24
Yes the dealer should. But they are not doing a thing except telling me how tough the parent company in Germany is to deal with. I would have thought they would have jumped all over this to show me how they take care of a great customer. I think if I dont pay Porsche financial until the car is fixxed the bank will consider me late and screw my credit. I dont think the bank cares how the company screws the customers
#25
Nordschleife Master
Yes the dealer should. But they are not doing a thing except telling me how tough the parent company in Germany is to deal with. I would have thought they would have jumped all over this to show me how they take care of a great customer. I think if I dont pay Porsche financial until the car is fixxed the bank will consider me late and screw my credit. I dont think the bank cares how the company screws the customers
Yeah, you will for sure get a ding on your credit report. Companies that do the credit thing just look at payments - if you are late they report it. They don't care if the non payment is justified or not - or should I say they consider any non-payment not justified.
#26
That is the problem. What leverage do I have to coerce them to act responsibly ? I am going to drive to the dealer tomorrow and try a d convince the owner, whose name the dealership is in to get involved and to call Germany and to demand the hose that they broke. The service advisor tells me they never worked on a turbo before, if you believe it. It was their inexperience that destroyed my vacuum hoses. The dealer breaks the car and stands it and tells me that I have a problem. What a bunch of non professionals they are
#27
Rennlist Member
Yes the dealer should. But they are not doing a thing except telling me how tough the parent company in Germany is to deal with. I would have thought they would have jumped all over this to show me how they take care of a great customer. I think if I dont pay Porsche financial until the car is fixxed the bank will consider me late and screw my credit. I dont think the bank cares how the company screws the customers
#28
Rennlist Member
Which dealer is this? Had an issue with one NNJ dealer with the radio in my Cayman. The PCM was freezing and locking up randomly. Restarts did not fix it but after the car sat overnight it was fine. This would happen a few times a month.
The dealer said Porsche refused to fix the car until
they had proof of the issue. Two visits later and finally a video I took and they repaired the car.
The dealer said Porsche refused to fix the car until
they had proof of the issue. Two visits later and finally a video I took and they repaired the car.
#29
Call PCNA and complain. After my dealer nightmare they sent me a nice check. I can't say they were very helpful in resolving it but realistically that's all they could do. I think they can also put pressure on the dealer well above the meager means of the consumer.