I need some education on how boost leaks affect the boost level readings. I've read that failed stock DV's can result in decreased boost and boost gauge readings. I've also read that boost leaks by wastegate conncections can cause increased boost levels. I'm a bit confused. Can someone educate me on how boost leaks cause different boost problems depending on the location of the leak? Will I get a CEL with all boost leaks, or only those that are severe? Thanks

 

DV's are the cause of a lot of boost leaks. When they leak, you will not get the full boost the turbo is making to the intake. In fact, this can cause the turbo's to overboost and spin too fast, thus damaging the turbo's. Any boost leak will most likely cause the turbo's to spin to fast. Often times you will not see this on your boost guage except that it will not register the max boost you're used to seeing. Most of the time you will not get a CEL for this problem unless it's very significant. I'm not real familiar with the Porsche Dealer scan tool, but I would assume it's similar to a Vag-Com in that you can watch while driving the boost that's being called for by the ECU and what's actually being made by the turbo's. This is helpful in diagnosing boost leaks. Hope this helps.

 

Last season I drove alittle in the snow and here in Sweden is it also alot of salt on the roads...

On the waste gate pistons I got a layer of salt which made them stuck...
Since they didnt go back all the way and closed I was stuck att max 0.4Bar... Took a while before BOLI on 9ff recomended me what to try
After that I saw the 0.8 and 0.9 again.
And now I see 1.2 all the time and is a happy camper

Regarding CEL, my fault did not throw one

 

Thanks for the replies. I understand that with a boost leak the actual boost will be lower than normal, and that can cause the turbos to overspin to try to make normal boost (which is leaking out) -- but why do some people say the boost reading will be too low (when DVs are leaking boost) and some say the boost reading wil be abnormally high?

 

I assume that is said that way because the reading on your guage will be low, while the boost the turbo's are making is very high.

 

I had boost leak problems as well. I think it can be difficult to determine the site of all leaks. I was leaking from a hose or two and also had a some kind of boost valve malfuntion (i can't remember name of valve, its not the DV..something else) My car would not reach or hold boost pressures of 1.2 as expected after stage 4 upgrade. I upgraded my hoses, had that valve replaced and upgraded the wastegate springs. Now I'll spike 1.3 and hold 1.2 at WOT.