boost leak? or wastegate issues

mojomello · Post by **mojomello** » 21 May 2011, 15:48

I installed a boost controller on my 940 and it ran awesome. However, recently the "pickup" got up and left. The stock gauge is showing that I'm boosting,(although not nearly as quick) and I'm hearing a "whooshing sound" as the turbo spools up. I've been over this thing a hundred times looking for leaks to no avail. If there WAS a leak, why would the gauge be registering anything? I'm at a total loss here, please help

kcjones · Post by **kcjones** » 21 May 2011, 17:58

"whoosh" indicates a heavy leak. You're probably still getting a boost gauge reading because there is still some boost, or the gauge readings are before the leak area and still have some psi. How far are you getting into the gauge? Maybe try a can of carb cleaner to find a leak. Every once in a while I'll use a lit cigarette (or the like) to find minor leaks. Hope it helps.

mojomello · Post by **mojomello** » 21 May 2011, 19:31

I did a quick pass with some carb cleaner before it got dark. No idle increase when I sprayed it in the most obvious areas. I'm gonna get another can and try again in the morning, so if you have any pointers I'd be more than happy to give it a try. This might be a dumb question, but could it be in the intercooler?? Oh yeah, the gauge is registering normally, which is about 60% into the white, it's just climbing slower than it was before.

kcjones · Post by **kcjones** » 21 May 2011, 19:40

Might be the controller itself, then.

mojomello · Post by **mojomello** » 21 May 2011, 19:58

Just tried it. I took it off altogether and took it for a spin, no signifigant differance, just a little less "whoosh"

Post by **Glencoeteen** » 21 May 2011, 21:02

CBV Valve? I know your's is a 940 but I just changed mine today on my S70 T5 and it built boost faster and held it.

mojomello · Post by **mojomello** » 22 May 2011, 10:38

just took off the cbv, and the diaphram seems to be in perfect condition. I'm making a soapy water solution right now and hopefully I'll see some bubbles in an inexpensive, easy to fix area

mojomello · Post by **mojomello** » 22 May 2011, 13:48

the soapy water test revealed nothing. I disconnected the battery for an hour, and the problem persists. I'm starting to think it might be a crack in the intercooler somewhere, although I can't see any with it still being mounted in the car. Is it safe to pressurize the system using an air compressor and a pressure gauge? I think I can build something similar to the way we pressure test pool plumbing using pvc...

kcjones · Post by **kcjones** » 22 May 2011, 22:49

Wouldn't it dump out of the wastegate?

mojomello · Post by **mojomello** » 23 May 2011, 15:19

my plan is to disconnect at the turbo outlet and clamp onto the contraption I've already built out of 1 1/2" pvc which consists of a 1' length of pipe, a pressure gauge, vavle stem and a friggin hose spiggot to bleed off any excess pressure. I'm hoping that at the very least I'll be able to get enough pressure to build up in there that I'll be able to hear the leak, since it's only audible under heavy load. I have no idea if this is gonna work, but I really can't afford to throw parts like intercoolers at this if it's not even the right part. My only real concern is that a 3/8" air compressor hose won't fill it up fast enough for it to pressurize to 12psi.