We are having some weird issues with the Switzer P800 kit on 2 997TTs, if anyone has an idea of what's going on please help!


background - 2 identical 997TT Tiptronic, with Switzer P800 kit and flashed with Switzer tune(durametric??), both tip trans are upgraded by switzer.

both cars were 100% stock with no mods.


issue after installed Switzer p800

the car pulls hard when cold and hits around 16psi(supposed to hit 21 but RPM signal was not being picked up by EVC, and Switzer adds 1psi per 1K RPM from 3K)

after several pulls, car warmed up, the car starts to drop boost like crazy. it barely hits 14psi, and in 3rd - 5th gear, it slowly drops to around 10-11psi as RPM climbs.

I can hear some BOV venting sound when boosting, seems like BOVs are not holding.

after longer driving when car is hot, it may reach 4psi at most in most gears, and will drop to 0psi after 5K RPM.

so from there after, no boost, the car will not hold any boost at all.

but if we shut off the car and restart, it holds boost again but not as much, maybe 10psi, then several pull later it's back to zero boost again.



Anyone got any idea what may be happening?


I checked and rechecked all vacuum lines, intercooler pipes, everything are in good working order and no leaks.

the BOVs are T'd into the stock fuel pressure regulator.

both cars are having the exact same issue!

 

I'd check the y-pipe connection to the throttle body & plenum that hose is where mine always popped off or call Switzer i'm sure they would help you out.

 

Sounds like a boost leak. Once the PCM detects it, it will not allow boost. The bov noise you describe is most likely the boost venting.

With the help of a friend and a little brake boosting while not moving, you should be able to locate the source by the noise of the actual boost leak.

Good luck.
Mike.

 

the boost is now controlled by HKS EVC boost controler, and the car now runs MAP (no more MAF) at least it won't be at zero boost right?

and i can't understand why the car would lose boost when it's hot and after several runs.

there's no leak in the pipe connections for sure

 

There's a leak in the boost system somewhere - for (99+%) sure.

The fact that the car starts out sort of okay and then fades is symptomatic of the ecu pulling boost (going into limp mode) to protect the car when otherwise it would call for the turbos to spin up to "eternity" trying to hit whatever boost target is programmed in the ecu. The "whoosh" you hear is the leak or the brv's trying to save stuff. It might be a failed hose or it could be a loose connector. If the ecu doesn't protect the power plant, when a turbo fails at high rpm's, all bets are off.

The only other possibility would be some sort of anomalous ecu programming since two cars seemed affected but I would think this is a very long shot. I'd give Switzer a call. Do you have the equipment to do a proper leak test? Best

 

Its p3402 or p0234 (pivis), means that u reach too high boost and ECU drop it or off.
We have same porblem on 3 cars, 2 with 3076 turbos and one with 3582

 

OP, This makes sense if you are sure all the boost hoses and connectors are intact and properly installed. If the tuner raised the max boost pressure but failed to raise the safety limit or raised it inadequately, then the ecu would pull boost (hence the initial drop) and eventually put the car into limp mode (the 4 lbs scenario). When you turn off the ignition and restart the car, the cycle starts over again.

Switzer enjoys a fine reputation and it would be a surprise if this issue were directly attributable to them so a couple of questions; Did you have the work done directly by Switzer or did you buy the car with the package installed and are taking someone else's word that it's a Switzer tune/kit? Was the ecu modified by another shop that "installed" a Switzer product under some form of licensing agreement? Was the car tuned on a dyno when this work was performed? Has anyone else worked on the the ecu since the tune was installed and/or have other modifications been made?

I really hope it's just a loose hose as those are easy to fix. If it's a programming issue that is directly attributable to Switzer, I would think you could send the ecu back to them for recalibration. If a third party is involved, things could get rather complicated. Good luck, hope it turns out okay.

 

thanks alot for the information guys.

To reply Steamboat, MegioN

I actually sold the Switzer P800 kits to this shop in China, and I ordered them directly from Switzer. I also went to China to physically check the installation, and also used the ECU flash software provided by Switzer, and made sure the ECU was flashed correctly.

so they are legit.

I understand overboost sets off some warning, but it's reflashed to Switzer spec, and the stock ECU no longer controls the boost solenoid, as they are being controlled by HKS EVC now. I don't see how the ECU can influence the boost pressure? or maybe the ECU backs off the throttle or something?



also, there are 3 large plastic hoses hanging in the engine bay, they are left unconnected. the shop had no idea what those are for, my guess is they are the stock BOV vent hose going back to the stock turbos.

 

Id be concerned about 3 hoses hanging in the engine bay unconnected!

 

+1 gmoney. Basically everything on a Turbo has a purpose so that I would say should be the first line of investigation.

 

If they eliminated the airbox with larger blow by type y-pipe like i'm doing (non switzer)& side air intakes in the wheel wells you end up with several hoses in the engine bay that go no where(they would have went to the airbox which is now eliminated ) ,you have to drop the motor to eliminate them all together from what i understand.

 

yea those 3 hoses were for vent and not pressurized.

the air intakes/ filters are now in the wheel well by the intercoolers.


you guys think any chance of the ECU is throttling back on its own?
because the BOVs are very obviously blowing off under WOT / full throttle, i can clearly hear the sound of it. the only thing that can cause this is the throttle right? i don't see any changes in the vacuum source, since it's connected to the HKS EVC, and the readings are the same.

 

I as wondering what the outcome was, as an am having similar issues with my turbo. It has been at a Porsche shop for over 2weeks and they still can't fin the issue!!