Hi Everyone. I am in the middle of an upgrade cycle on my 2005 996 TTS Cab, and have come across a problem. My car has the following mods:

- K24/26 turbos
- CF Air intake
- Billet Diverter valves
- Plenum
- Throttle bodies
- 5.0 Bar FPR (FVD)
- Gemballa Exhaust

I had originally been having some issues with overall performance using a PowerChip flash. At the time, I was only hitting 0.9 bar on WOT. As such, I decided to switch to FVD programming and simultaneously added the 5.0bar FPR. It turns out that in that process a boost leak was identified and fixed. Presto, I'm hitting 1.2bar (peak according to in-dash meter) and life is good. Soon after the programming is in effect, I get a CEL that is pretty intermittent. The car is still running great and I put off taking the car in, as I assume it is just something to do with the new programming and life was very busy.

So about a month ago, I'm doing some WOT runs with a friend in the car, and noticing that the car is just not pulling like normal. Turns out that boost is only hitting 0.7 to 0.8 bar. I naturally assume that it's a boost leak again. I take the car into my friendly mechanic at Porsche to read the code and check for the boost leak. He tells me that it is something to do with the diverter valves and since they aren't stock, he can't do me the favor of replacing them under warranty. He doesn't seem terribly sure of himself. So I speak with Mark at FVD. He says that based on the code (secondary air injection system) that it is probably the diverter valves. So the upgrade/fix cycle begins.

I bought a set of silicone boost hoses from Vivid, and decided to put in a HKS boost controller as well. I take the car to Lucent and Tom has been working on it. First he installs my new JIC Cross coilovers (thanks Tom!), and then starts on trying to figure out the boost leak issue. To him it seems that the diverter valves are completely fine. He checks for boost leak with smoke and finds nothing, and double checks all of the boost and vacuum hose connections: nothing. Everything seems right.

While he is sure that the DVs are fine, he is going to replace them with stock units and see what that does. His next idea is related to the FPR. Does any of this sound familiar to anyone? Any ideas on what this could be?

 

does sound like a boost leak but if he pressure tested everything and was fine then i dont know what to tell you ...

 

reset the the ECU for 10 minutes via battery disconnect....

pressure test the car... the CEL is probably from a bad cat...

 

I would check the last thing that was touched I'm guessing it was the FPR, A pressure test from the intake side will not make its way into the intake manifold since the TB is closed so it wont tell you everything. The line the goes to the FPR is a hard line pushed into a rubber line, I have seen those come off plenty of times.

Chris Green

 

I have the same car with fvd stage 4 chip and speedtech exhaust, and my car consistently hits 1.2 bar, but last week it was only hitting .8 bar I suspected bad gas since fill up it's back to 1.2 bar.

 

Thanks for the feedback all - I will try all of your suggestions and get back with an update tomorrow.

 

make sure everything gets pressure tested, including f hose. i just had that rupture on me a few days ago. although i didnt have a cel light...id still check.

 

Ok - so it turns out that the f-hose did not have a good connection to the CF cold-air intake. Not sure why this didn't show up the first time, but it's solved! Thanks for everyone's help. Now making 1.1 bar again and life is good.