I know I don't post over here a ton, but I am desperate for new ideas. For the past 5 weeks, there has been a ghost haunting my car.

The issue with the car is, it continues to go into limp mode and the only code the comes up is P1250, Boost Pressure Control Deviation - Above Limit Value.

I assumed it was a boost leak, so searched and searched to no avail, so I gave up and took the car to GMG. It has been there for a month and they came to conclusion that is was the passenger side turbo. With that diagnosis I purchased some K24's and had them put on the car. Unfortunately there was, no change after purchasing new turbos and replacing them. Car still goes into limp mode every time after hitting full boost.

The car has 36,900 miles and a few mods. GIAC Tune, Billet Diverter Valves, Cargraphic Exhaust, BMC Air Filter and now K24's, but I would prefer to go back to my K16's when this is over.

The other items that have been checked or replaced are the following:

N75 Valve
Tune
Exhaust/Cats
Diverter Valves
Boost Leaks
Intake
MAF
Boost control sensor.
Wastegates on new and old turbos.

I am have been reaching out to everyone I know, as this is driving me nuts!

If there is any input you have from you vast wealth of knowledge I would forever be in your debt.

Thanks for taking the time to read my sad story.

Danny

 

Hi mate, I saw your posts over at the other forum... I used to post there but they banned me for supposedly having multiple accounts (the others were for my 78+80 year old neighbours)... anyway, I read everything on your thread in depth...

You did say initially when you reflashed your ECU to stock that the problem went away... MY car HAD an old GIAC tune and I had the same problem you did... luckily for me only once...

I did some leak tests, found some problem with my coolant, flushed the system with new coolant, bought Eurodyne software and reflashed the crazy GIAC tune (which was way too much power for my stock set up and was introducing crazy 35-40* timing at times) with a base Eurodyne tune.

I never had the problem again after I went to a more normal flash.

My understanding of the old GIAC tunes (which your car had) was they were written en-masse for any and all 996 TT with some very dangerous and basic fuel and timing/boost remapping. My car would go to crazy 1.5 bars overboost once it hit near max revs... so from 3500-4800 rpm my car would pull timing to keep up with the silly GIAC 1.3 bar tune (overboosting), then try to dump in fuel but my DC% on the stock system was ay over 100%, then above 5800 rpm to 7000 rpm it would get THAT CRAZY boost SPIKE..

Anyway, here are some codes that come up

P0045 Charge Pressure Control Valve Output Stage - Open
Circuit
Possible fault cause
♦ Charge pressure control valve (coil) open circuit
♦ Open circuit in wiring
P1109 Input variables, charge measurement - above limit
Possible fault cause
*Heavily soiled throttle
*Throttle adjusting unit faulty
*Mass air flow sensor faulty

P1250 Boost Pressure Control Deviation - Above Limit
Possible fault cause
♦ Bypass flaps incorrectly adjusted
♦ Turbocharger faulty

So possible MAF, clean throttle body and waste gates

DID GMG try your car as it was with the STOCK ECU flash ?

After my problem went away with my solution, it developed other issues so I took it to the best Porsche guy here in NY......... He also found other problems... I now have a new fuel system with ID1000s, new clutch, new coils n plugs (coils were all cracked) plus plus....

I know you are in California etc and I am unsure of what GMG does as far as our closer to stock cars goes (I know they are really a race shop). I found race shops here in NY were effing useless with my BMWs and Lotus etc as they were more interested in making big $$$ doing big builds. I understand they have a good reputation but sometimes a 2nd opinion can help.

FWIW My car is a 28000 mile TTS 2005

 

I should add that my car has the EVOMS vflow intake, not sure what MAF set up you are running

there are some threads from around the net I read about this here at

http://www.renntech.org/forums/topic...oost-pressure/


http://www.6speedonline.com/forums/9...oost-help.html


http://www.6speedonline.com/forums/9...rs-help-2.html

 

Thanks for all the input! GMG did put the tune back to stock and the problem persisted. They also updated the GIAC file after the K24's were installed but no luck there either.

 

Check out this link- disregard the serpentine belt issue, read down. Good luck
http://www.6speedonline.com/forums/9...tine-belt.html

 

I will have them look into that.

Thanks!

 

I have not had a chance to try any of the EVAP equipment, but tried replacing the MAP sensor. Problem continues.

 

the what?

this from that thread: < I had the p1250 and it turned out to be a boost leak.
I had to drop the engine because the plastic inlet manifold on bank 2 had come loose and lifted off the rubber connecting pipes >

...didn't you mention bank two somewhere in this?

 

MAP sensor at the Wye pipe.

The car goes back to GMG on Friday. I will have them look at the intake manifold. Really don't want to drop the motor!

 

sorry couldnt tell if you meant a tune ( remap ) or maf. got it. as always. good luck.

you my have no choice but to take that sucker out. jeez man, this is costly

 

Yes it is.

If I have to drop the motor, I will have the coolant lines welded and clutch done at the same time which only adds to the cost. At least my wife is stuck with me For Richer or for Poorer. haha.

 

lol i hear ya bro. sometimes i feel i'm married to the car.

 

If you're in socal you might want to stop by R2 Racing in Santa Clarita for a 2nd opinion.

Hope you get it sorted out soon.

 

I feel your pain brother. I had a similar ghost that no one could find for a year, turned out to be one of the CATS, which should have been one of the first things looked at instead of the last. Hang in there, it's something simple but hard to find.

 

Good luck mate, luckily over here my wife is the richer one now