The parts are going to end up in the classifieds . I have only really paid for the Turbos at this point.

Any chance the intercoolers could be the cause? Or am I (we) over thinking everything still?

 

What else should I have them try? The have assured me that they pressure tested the system with Nitrogen up 20 psi. I have even sent them all your responses .

I can take the car somewhere else, but then I am completely wasting money.

Call me optimistic, but I still have hope that GMG will make this right.

 

this is reading like a greek tragedy
i agree with "it can't be THIS difficult" o m f g. sheesh. you need to cut your losses at that shop.

 

Your posts always make me smile.

This has been an added stresser in my life, that I really don't need.

 

when i say i feel your pain, it isn't merely words on a page. sucks dude.

 

I"m sorry you're having problems. As you are probably figuring out, these can be very difficult problems to diagnose even for experts in a well-regarded shop like GMG. Literally, the underlying problem(s) could be almost anything and the limp mode and boost issues are merely the symptoms you see as the ECU struggles to protect the car. I chased similar symptoms around for well over a year and spent thousands of dollars in the process. The first time the problems arose we discovered many micro-leaks once we got the leak test pressures to 25 lbs. We thought we had it nailed but shortly thereafter similar problems recurred. After ruling out leaks once again, the shop tested everything they could think of especially focusing on sensors. Everything checked out within spec. As my shop is an affiliate with Evolution Motorsports which did my tune and build, they were consulted and verified the ECU files were appropriate and not corrupted. Because nothing physical could be found though we thought that it must be the tune. IMPORTANTLY, we were reminded that software does not rewrite itself so unless our problems were there from the get-go, which they were not, it could not be software related - it had to be hardware or mechanical. Eventually we deduced that since we couldn't find a physical problem, perhaps it was a failing sensor that periodically sent bogus info to the ECU which interpreted it as a condition to be prevented and, hence, pulled boost and went into limp mode. But all the sensors seemed to be within spec, etc. etc. Finally, after several visits to the shop and more out of desperation than any particular inspiration, we decided to replace the MAF's. On that final particular visit one of them tested just slightly out of spec so I held my nose and wrote the check for $1500+. Problem solved...or so it seemed. Next time at the track a few days later the car would go great for 1/2 lap, go into limp mode, pull boost, etc. etc. but then after toodling around for another half lap, the power would come on and everything was great - for another half lap. Rinse, repeat, etc., etc. I was very close to selling the car but after sitting on the problem over the winter with my guys consulting the Evoms guys we/they concluded it had to be something thermal; exhaust gas temps or the like. When they finally got their hands on the car this spring, we found a fouled catalytic converter that undoubtedly was raising the EGTs and increasing back pressure. We also found a header gasket that had failed perhaps because of the cat. So, after consulting with Fabspeed who supplied the exhaust and cats, we decided to ditch the cats, installed test pipes and replaced the gasket. The car has never run better than it is running now!

I guess the point of my rambling is that your problems could be just about anything and even great shops can get stumped by this stuff and there are no guarantees they will necessarily figure it out (sorry). I know firsthand of guys who have sold their cars because of similar situations that went unresolved. Now, that said, I would give GMG as much time as they think they need. I would try to understand and document what their line of diagnostic thinking is so you have a history of what's been tried and failed. I would try to be part of the process but unless you are an expert diagnostician and Porsche wrench I would pretty much stay out of their way. Their training and experience goes far beyond what you learn on these forums (although sometimes you can gain valuable insight). They are the experts and I would ask them to be honest with you and if/when they say they are out of ideas, thank them, pay them a fair price for their labors and move on. You might decide to bag it and sell the car or, alternatively, take it to a shop that is really well regarded for working with tuned turbos particularly those with a GIAC setup and get some fresh eyes and brains working on it. Tell them what has been tried (that's why understanding what GMG is now doing is so important so they won't have to duplicate work that has already been done) and let them put their hands on the car. All it takes is for one person to have that ah-hah moment and you will be back on the road with a smile on your face! But getting there may not be easy nor inexpensive. Good luck, best wishes and hang in there!

 

... now that was a helpful post.

 

Thank you for all the input! It is good to know I am not the only one who has had "ghosts" haunting their car.

I am way to emotionally attached to my car to sell it (First Porsche, First super car, drove to and from my wedding in it!). But I would like to have it at full speed again!

It is funny you mentioned that the cats were the cause of your woes. After checking for boost leaks and sensors that was the next thing GMG checked. They put a stock exhaust on the car hoping that was the issue, but to no avail!

GMG is also a GIAC dealer which was a big selling point when I decided to bring the car to them.

I am still hopeful that it is something relatively simple, it is just a matter of finding it.

I will say that GMG has been fair to this point. They are busy with racing and track prep, so my car has not been a priority, but they have been upfront about it and seem determined to find the issue.

 

Forgot to mention. It seems the problem is only related to bank #2

 

Just to keep the sad story going.

MAP sensor has also been replaced.

No luck.

 

Just had to share, for my own self pity. Week 7, no results.

I did have them install the new CSF radiators while it has been there, so that should be exciting.

 

You sound like a very nice guy for gods sake take your car somewhere else and at least have a fresh set of eyes take a peek. Loyalty only goes so far lol.

 

I hope it does not come to that, but you are not the first one to recommend it.

 

what problem is that? I thought the car goes into limp mode due to overboost.

 

The only code that is coming through is P1250 Boost Pressure Deviation, above limit.

It seems that the passenger side of the system is where the problem lies. GMG came to this determination by disconnecting the wastegates one at a time, while the car was on the dyno.