dubcaps

Alright here is the problem. About a week ago my car started making a fairly loud wissshhhhhiiiiinnnnnnnneeeee sound at about 8 psi on the primary turbo. The sound would get louder up to 10PSI then boost would drop down to 0psi at the transition and it was like the car hit a wall. I looked at the turbo system troubleshooting page but it confused the hell out of me. I searched around on the forum and it said under WOT to let off the gas so it goes to -20 on the boost gauge, then back to WOT, it stayed at 0psi. I took off the UIM today and didn't see anything cracked, split, busted or disconnected, but it was my first time ever looking at the rats nest up close so i was a little overwhelmed by it all. I replaced a few hoses that were questionable but overall everything looked fine. I got everything back together and I still have the same problem. I also read somewhere to block off the CRV and that didn't help either. I don't have excessive smoke coming out of the exhaust or any under hood so I don't think that the turbo is bad. Does anyone have any ideas on what it could be or where i should look? Any pictures pointing me in the right direction would be great as well.
If you've read this far I'd just like to say thank you and I'm open to any and all suggestions.
Thanks,
-stephen

911GT2

If the whoosh started at 8 psi, I'd think maybe a cracked intercooler coupling or something to that affect, that only showed itself after 8 psi.

Does it always drop to 0 psi after transition? Or does it not make any boost now?

dubcaps

All the intercooler couplers looked good. I checked those when i pulled off the UIM. It always drops to 0 PSI at WOT at the transition. I also forgot to mention in my previous post that the sound seems to be coming from the passenger side.
-stephen

TTBullet

i'm having same issue, when i shift to next gear up, it makes "shooong" sound (after 4500rpm) at the transition, boost (14-8-5, PFC). fowllowings are what i checked: check valves, press chamber, vacum chamber (checked if full of oil, none), replaced uper turbo control solenoid valve, replaced lower turbo control solenoid valve, turbo precontrol solenoid valve, westegate control solenoid valve, actuator wastegate control, acturator turbo precontrol, actuator turbo control, and i'm still having same issue.
the primary turbo fan seems no free play, but secondary turbo seems it has free play, meaning if i spin it with my index finger it spens well, but primary fan seems turn slightly harder. please feel free to comment.

thank you

BinaryRotary

Check to see that the Y-pipe flange nuts are tight. The one coming off of the secondary turbo is hard to see. It is hidden under the secondary turbo intake pipe and often gets overlooked. If it is not tight you are just pumping boost into the atmosphere.

dubcaps

alright i'll check that and post back in a few.

dubcaps

all the nuts that i saw looked and felt tight, but i might have been looking at the wrong nuts as there is a lot of stuff in that area. not to sound like too much of an idiot but can anyone supply me with a pic or two?
thanks

Snook

iTrader: (12)

hey man how are you
thanks again for the pics of the dad seats

if you want to search for a leak its simple...take 2 tennis *****, take off the filters and stuff them in the holes as much as possible, now use one of the nipples on the uim and get an air compressor with the right fitting to go over it. I got mine in the car part section at walmart it was a blue package like 7 dollars with a few adaptors one that fits perfectly over the nipple. Now you shoot air in there until you hear air escaping and that is your boost leak. Should take 15 minutes once you get to an air compressor and seconds after putting air into the uim to hear or feel the leak. Sounds like a big leak should be easy to find

good luck

dubcaps

dude thats an awesome idea, i just need to get an air compressor and i'm set. any idea what the actual part from walmart is called? I'm going to have to check that out tomorow.
thank you!

Snook

iTrader: (12)

its in a blue package about 12 inches long and 6 wide
just near the air compressor ****...one of those adaptors worked for me at the gas station I went to.

you just need to find anything that will have a perfect seal because if its leaking right there youll hear that noise instead of the leak. Its all gotta be quiet and pressurized

good luck bro

Flybye

Look at the y pipe coupling and take it out.
Reason is because when they have a split, it will be tight enough to not be able to see, but under pressure the thing will open up like a $10 ho allowing your boost to leak out. You need to physically take it out or squeeze it in on all sides. This is the common problem most people neglect to properly check by simply doing a visual.

Snook

iTrader: (12)

theres 2 couplers for the y pipe and the 2 intercooler pipes pretty much is what everyone is saying. Im sure you already know that is where most leaks happen especially big ones like yours

for the lower intercooler pipeyou need to take it off and squeeze and bend it to find the crack most of the time. The top one you can do that while its on the car. With the couplers it should be noticeable if you just feel them while on the car also.

remember if its not a leak then one of your solenoids or valves has gone bad. so this is the best place to start

dubcaps

alright, thanks for all of the advice guys. I removed the y-pipe coupler earlier and it seemed fine, but it never hurts to double check. I hope to be at the bottom of this tomorrow. Then I can finally feel the effects of my new greddy exhaust on the butt dyno =D.
-stephen

also, good analogy flybye =D

r1owner

Is it possible for the intercooler to leak? If so, how would you test it?

technonovice

I know a well versed boost guy here in Raleigh who can help you. If he has time, it would be worth your money. PM me if you are interetsed.

Snook

iTrader: (12)

dub how id dit turn out?

and yes a stock intecooler could leak. this same test would lead you to the leak

i wouldnt waste your money, most rotary mechanics charge 75 an hour and know less than you and I

dubcaps

i havnt gotten a chance to test it yet, i'm getting ready to make a run up to walmart in a few to get those fittings. i'll let you guys know what happened a lil later tonight. thank you for all the help, i hope to be at the bottom of this shortly

Snook

iTrader: (12)

i happened to go to walmart with a friend just now

its called 7 piece blow set or something and it was $6.98
the long tube is what I used from that and nothing else when I was at the gas station.

dubcaps

I finally got everything i need and just got back from walmart. its too dark to try to find the leak so its going to have to wait til tomorrow. sorry for all the delays, ill let you guys know what happens tomorrow. once again thank you for all the advice and imput.
-stephen

dubcaps

well apparently my girlfriend's air compressor was too weak so i gotta use another one. Did you say you used the tire inflator at the gas station surge? thanks
-stephen

clayne

If it's the secondary only it could pretty much only be two things:

Charge Release Valve (doubtful) - looks like a brown blow off valve near the back.

Y-pipe to secondary turbo flange.

Now it *could* be any other portions of the intake piping, but you would generally see that in primary turbo use as well.

dubcaps

i think its definitely something related to the secondary as the woooooooosssssinnnnnnggggg noise doesnt start til about 8psi on the primary. then when its supposed to transition boost just drops to 0psi and stays there with that same annoying sound. i read somewhere to cap off the CRV to see if that changes anything, but it stayed the same so i don't think its the CRV.

maybe the secondary turbo is bad, are there any tell tale signs of this? I'm too lazy to search at this point in time.

thanks,
stephen

clayne

Turbo just doesn't crap out like that.

It's a boost leak, for sure.

dubcaps

thanks clayne -D. ive lined up use for a better air compressor for hopefully i'll be closer to finding the problem tomorrow.

Snook

iTrader: (12)

jeez dude I could have rebuilt an engine in all the time this is taking you haha. get it fixed already. I used the one at the gas station yeah park as far away as you can with the hose reaching so its quiet near the engine bay