Turbo problem

Hey!

I have a 2010 LGT and yesterday i installed the Cobb ap stage 1. I went to try the car, did 1 reasonnable acceleration and saw the turbo boost all the way to 15 psi on the oem gauge. Then the car lost a lot of power, turbo gauge stuck at 0 mark. I uninstalled the app, now the power is back but not all of it. Turbo gauge still stuck, turbo seems unexistent and the engine stutters at idle...... any idea what is happening?

Possibly blew a vac hose off somewhere. Common symptom is a rough idle

Well i just realize a strong air leak is coming from top of the engine. Am i corect to assume either the charge pipe is leaking, or another pipe?

when you get on it, is there a fart sound? It could be the IC to TB coupler that is loose

the leak seems to be coming from between the manifold and the intercooler. there a plenty of hoses there, including that coupler. I can't feel the leak from top. are there other turbo related hoses/parts that could be leaking in that area?

 

leak is coming from somewhere in there. can't feel it with fingers

As Zee mentioned it is a 99% chance that it is the throttle body to Inter cooler hose. It is a common issue on these. You will find a bunch of posts about it. Easy fix at least.

There is also a little-finger sized hose that connects under the manifold by the intercooler that can blow off. I put a worm clamp on mine. It comes from the passenger side of the engine and makes a tight 90 degree turn onto a nipple poking out from under the manifold. You pretty much have to uninstall the intercooler and put your head where the intercooler used to be to see it.

 

Pro tip: Mark the orientation of the TB-Intercooler hose before you take it off. It's a bitch to get rotated right if you don't.

^ is the one you are thinking of this one. I have this old photo taken for times like this one. might be a pain to get to it under the manifold.

I found it. It was a small rubber hose that disconnected from a T from another hose that runs under the TMIC. The air whistle was actually a vacuum one from the T. Put it back with a tie wrap and everything is back to normal. I think this is where the boost gauge hose (the one disconnected) is connected. Thanks everyone!!!

^ is the one you are thinking of this one. I have this old photo taken for times like this one. might be a pain to get to it under the manifold.

 

Yeap that's the one!

 

That's a good photo to show where the PCV valve is too.

Well here i am at it again!

This time, the car boost very slowly and won't reach the 15psi max (13 instead).

No rough idle at all. Am i right that this is clearly a boost leak?

Did you fix the blown off vac hose/tee?

 

I had this low boost issue when I first flashed the Cobb OTS Stage1 tune, it would only hit 12 or 13 psi. It turned out that the throttle body coupler hose (between TMIC and TB) was leaking a little. I tightened it up and hit target boost no problem.

Well i ordered the perrin coupler since it is probably where the leak is. I flashed it back to stock and only reach 6 psi.

Would it be a good idea to change the hoses for silicone ones? Any kit available?

No kits available, but most of the small lines are the same size. Try doing a boost leak test. I will try to find the link. Its fairly simple take out the airbox plug the intake hose with a container or bottle large enough to clamp the hose off with. And then remove the boost signal line and feed air into it with a compressor and listen for the leak.

Link to boost leak test.

 

http://legacygt.com/forums/showpost.php?p=5458572&postcount=33

Well after installing the perrin hose between the Intercooler and throttle, i'm not sure

What to think. Car reaches 14.7 - 14.9 psi on cobb stage 1 hwg (goal is 15), but i still feel the car is slow to answer.... i'm gonna have it checked at a local shop.

Don't the Cobb maps aim for 15 psi plus or minus 1 psi? That makes you spot on I'd think.

Don't the Cobb maps aim for 15 psi plus or minus 1 psi? That makes you spot on I'd think.

 

It depends on what gas you have available, 91 and acn91 are 15 and 14 respectively. 93 is 17 psi. The hwg, lwg, and nwg all have the same boost targets they just have different WGDC to reach the target boost or tune it down if you are overboosting.

I'm running 91. Well maybe it isnt the turbo at all... feels like the car is weak on low rpm (1000 to 3000 rpm) but is allright after that!