Vacuum/Boost Leak - Need HELP!

[derfdog15]

Hey guys,

I went to run my car at the track this weekend (Sunday) expecting to run atleast 12.5 or better possibly. First run out of the gate was a 12.9 so I felt O.K, every subsequent run was in the 13.9-14.5 range, so I figured something was wrong with the car, took a look at the boost gauge, and got some logs - sent to AJP - don't have them with me at work- and it looks like the car was SEVERELY underboosting (ie. 4 psi at WOT).

I checked all of my added vacuum/boost connections due to the Tial BOV, MV-S wastegate, etc. and didnt see an issue.I started the car to let it idle, and heard an air rushing noise on the drivers side, a little near the rear of the engine bay. Took a look at the CAI, and the coupler wasnt sitting on the factory piping, there was a gap, I assumed this was the entirety of the issue. Fixed it, however there is still an air rushing sound. There is another coupler near that area, that is an OEM clamp I have never touched, and I am afraid it may be warped.

Here is a pic from google,

The clamp I am concerned about is pictured right behind the hose connector. It seems that part of it is mated to the pipe as a one-piece assembly? however on the end facing the rear, it seems warped, but when putting my hand near it I do not feel any air.

Any suggestions would be appreciated. When I am home from work, I plan to let the car cool off, then jack it up, and double check all of the charge pipe connections that I can.

Edit: added pics of how the CAI was (now fixed) and the coupler I am concerned about. After fixing the CAI connection, I can get to 10-11 psi, but should be seeing closer to 16, or at the very least 14.5 as that is what the boost regulator is set for.

Thanks guys

 

[ZSHO]

I would suspect it's coming from the brake booster "check valve."could be your culprit. Z

 

[derfdog15]

I would suspect it's coming from the brake booster "check valve."could be your culprit. Z

Got a picture of that location? and possible a part number/install instructions?

I'm going to check at the dealer later. Seems if it is that, it should be covered under my powertrain warranty. BUT since the car is modded, per my sig, unless its a super expensive part, or really involved install, probably not worth it to risk having the car in the shop, since I would have to swap downpipes, charge pipes,CAI,MAP, possibly stat,  and retune to stock.

I plan to go to the dealer parts department this afternoon. If there is an easy way to check that booster would be great as well.

Thanks Z.

 

[ZSHO]

The two gray valves probably have a hair line crack which is causing your issue.
I would also check the plastic ring which could be "split" on intake. Z

 

[derfdog15]

That is pretty much right where the sound is coming from. Still odd that I can't get full boost due to that? And the brakes are fine as well, I know when I had a vacuum leak on the brake booster line previously I had like 5% brake functionality.

I'll go by the auto parts or the dealer this afternoon and grab the check valve just to be safe.

 

[ajpturbo]

I dont think that line would bleed enough boost off...im thinking a large charge pipe connection or what about the end tanks of the intercooler....you were severely underboosting and wgdc was sky rocketing trying to achieve the targets....but you exceeded the underboost timer and it dump all boost and wgdc went to 0 i guess to protect itself

I looked at the logs again and you were at around 90% and barely at 5 or so psi...there should be a big release somewhere on the charge side so from compressor outlet and including the intake mani

What about your connection for the gate mod regulator?....i cant remember if you had a welded pipe or used the adhesive...maybe that was miwiau?

 

[derfdog15]

I dont think that line would bleed enough boost off...im thinking a large charge pipe connection or what about the end tanks of the intercooler....you were severely underboosting and wgdc was sky rocketing trying to achieve the targets....but you exceeded the underboost timer and it dump all boost and wgdc went to 0 i guess to protect itself

I looked at the logs again and you were at around 90% and barely at 5 or so psi...there should be a big release somewhere on the charge side so from compressor outlet and including the intake mani

What about your connection for the gate mod regulator?....i cant remember if you had a welded pipe or used the adhesive...maybe that was miwiau?

Mine is welded, I have a piece of hump hose between the welded flange on the regulator mod, and the outlet on the charge pipes. That is tight.

Based on where the sound is coming from, I would think it either is an intercooler connection, or right at the rear turbo. Its driver side, and sounds like its from the back. I'll double check the booster just in case, but it seems much to small to be still causing a 5psi loss - I am able to get to 10-11PSI at this point, rather than 5.

Worst case scenario, my dad, who has been a mechanic off and on for years, will come visit and help me track it I can't find the issue my self. Hopeing for something simple.

 

[SHOdded]

That coupler/U-pipe looks busted and needs replacement.  I think Z is on to the trail, we had one other member have an issue with a pipe in that area before IIRC.

 

[derfdog15]

Yeah I am thinking the coupler is the are of fault, thats why I posted that third picture. I think the U pipe/coupler in that area got damaged some how, and shifted back, and due to the shift back thats why the CAI got loose as well.

I can shift it even with the clamp all the way down. I'll have to get a part number or part from the dealer and replace it if possible. IDK if that coupler is part of the piping or separate.

Seems like it is split where I posted the pic, as it has a flap like opening on it.

On a side note- Called Airaid and told them that my CAI had been sitting loose, and I feared that the coupler had been warped. They sent one out free of charge. So far both times I have called them about a part I needed, they have sent a replacement free of charge, so definitely good service on their end.

 

[ajpturbo]

You can take off all the compressor inlet piping from the cai to the turbos and that wont make you lose boost.....it has to be from the compressor outlets to the intake manifold

 

[SHOdded]

Airaid :thumb:

 

[bpd1151]

Funny to see an old pic of my engine bay still floating around out there.

Gotta love Google. Lol

Sent from my SM-N920V using Tapatalk

 

[derfdog15]

Funny to see an old pic of my engine bay still floating around out there.

Gotta love Google. Lol

Sent from my SM-N920V using Tapatalk

I was like 99% sure it was yours due to the carbon fiber cover, so figured I would see if you chimed in, plus it was the correct angle.

Update: I am able to get the car to make a bit more than 4 PSI, but it alwayhs falls back down, ie. it goes to 4 psi, holds, and then spikes a bit, falls down again. The 10-11PSI I was seeing is still possible, but it tappers back down to 4 after a period of time.

My dad is driving up (From florida...I feel terrible he is driving all this way cause my car is being shitty) to help me diagnose. I checked all the connections I could, everything seemed tight, I even sprayed a soap and water mixture on the clamps/ connections I could get to, to see if it would bubble, but that did not occur. The issue seems to be comming from the rear turbo connection area, and I am thinking something is loose back there, but its a pain to get to it, and I have a lot going on for work.

Hopefully with the help of my dad we can find it and fix it.

 

[bpd1151]

Have you verified both of your BOV's are functioning as designed?

The symptoms you've described are nearly identical to my own experiences when (one of the two) OEM BOV's crapped out on me.

Worth an inspection at the least, as they're not that difficult to R&R.

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[Frozen Blue]

Did you mess with the lines that go to the EBC or to the turbo wastegates at all? Wastegate spring pressure is around 4-5psi IIRC.

 

[derfdog15]

Have you verified both of your BOV's are functioning as designed?

The symptoms you've described are nearly identical to my own experiences when (one of the two) OEM BOV's crapped out on me.

Worth an inspection at the least, as they're not that difficult to R&R.

Sent from my SM-N920V using Tapatalk

I'm running the Tial Q, no stock BOVs, but I am considering if maybe it is somehow faulty. I can't check it though without someone else to watch it or someone else to rev the car. I may swap back the OEM BOV portion of charge pipe to see if that fixes it.

Did you mess with the lines that go to the EBC or to the turbo wastegates at all? Wastegate spring pressure is around 4-5psi IIRC.

I havent been under the hood since december when I installed the charge pipes and downpipes. Car was running fine till I got it to the track and made  a pass.

 

[Sabtaj1]

Well.  You could always do the old brake clean trick. Start the car up and while idleing, start spraying around the hot side of the pipes until you hear the motor rev up and then you will find your leak. Just a thought.  Can't say I've never done it before. Lol

 

[Sabtaj1]

Well.  You could always do the old brake clean trick. Start the car up and while idleing, start spraying around the hot side of the pipes until you hear the motor rev up and then you will find your leak. Just a thought.  Can't say I've never done it before. Lol

Never mind. Don't do it.  Just saw you have the hot pipes.  Not good on the paint.  LOL. 

 

[derfdog15]

Well.  You could always do the old brake clean trick. Start the car up and while idleing, start spraying around the hot side of the pipes until you hear the motor rev up and then you will find your leak. Just a thought.  Can't say I've never done it before. Lol

Never mind. Don't do it.  Just saw you have the hot pipes.  Not good on the paint.  LOL.

I did basically the same trick using soapy water. Should have seen it bubble if I found the leak, but to no avail.

At this point the two thoughts are either stuck/sticky BOV, or a loose connection near the turbos which I was unable to get to easily while checking.

I'm hoping it is simply a loose connection near the turbos, but if I have to go back to OEM pipes to fix it, I will. Rather have a car that performs and MAY burst a plastic pipe than have a car that cant make boost. Of course if thats the case, I'll figure out what needs to be fixed/replaced to make the EPP pipes work again and go back at it if possible.

 

[8nutz8]

just a thought here. . did you go up in elevation to the track where the issue occurred?
before Brad made some adjustments to my tune, if I drove up in elevation significant amount the turbos would max out and couldn't reach desired boost and ECU would default to the mechanical wastegate spring setting of four psi.

IIRC from looking at your logs you still had some room in your WGDC before your turbos are maxed but it might be something to check. do you have a log from your 12.5 pass? if so see how hard your turbos are working in that log.


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