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Losing boost pressure on occasion


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Yeah I think the next best thing is to actually properly tests it for a boost leak and go from there. Is it possible for a turbo to be bad and not build proper boost without making noises? It has the factory turbo on it still with 135k miles.

 

I find it very interesting that on the fine learning knock correction I get just a little bit on 2 lines and if you follow over to my boost level it has a hiccup and fluctuates up and down right at that moment. That may be a normal thing for knock, I'm not sure.

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Alright I went into work today and pinched off the 3 lines off the intake before the turbo and pressurized the system to about 5psi with soapy water sprayed around. I didn't find any leaks so I bumped it up to 12psi and then all of a sudden it was bubbles galore from the AVO TMIC to the turbo and from the IC to the wastegate.

 

I tried to tighten the IC to turbo but it was as tight as I felt safe tightening it so I put longer bolts in it with nuts on the back side and it still leaked. The bottom wastegate bolt was stripped an just spun in the hole so I drilled it out and put a helicoil in it and it was good and didn't leak anymore.

 

I ordered a mr gasket thermostat gasket for the IC and I'm going to see where that gets me. The gasket should be in Tuesday. I also read on a boost leak tester website that especially on subaru's you should always remove the oil fill cap while testing and when I did that all the air blew right out of the crank case so I put the cap back on and it pressurized fine.

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Your IC isn't connected to your wastegate... you're probably talking about the BPV. When you helicoiled, I hope you took the entire TMIC to do it and you really, really cleaned the inside well of all the aluminum shavings.
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Yes bypass valve, that's what I meant to say. I did have it completely off the car and sprayed it out with brake clean and made sure all shavings were out of it. The bottom one that I put the helicoil in does go all the way through but the top one on the AVO does not. The brace for the IC is out of line so I don't have that connected and I hope that isn't why it leaks. I'm thinking about taking he brace off and bending it so I can mount it properly to the IC. It's about a centameter from being lined up.
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I installed the new gasket today and pressure tested again and it held pressure for a long time. Before it was 1lb per second and now it was like 1lb for every 3 seconds. I'll see how it does the next couple of days.

 

I still have yet to hear back from shamar.

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Here is a log and LV i did tonight. It's been 3 days sense I fixed the leaks I found.

 

http://i1286.photobucket.com/albums/a606/yfarmeaahka/EB25F6BF-B54C-46B6-A961-65536D3DA740-19731-000002462186ED82_zpsec310a84.jpg

 

I feel like its a lot batter than what it was but its still not hitting target boost near soon enough.

romraiderlog_20130228_181412.csv

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I got a response back from Shamar and he said he didn't see anything too bad, the knock was just noise or it would have been stored in my LV. As for boost I would need either smaller pill (1mm or smaller) or an ebcs to hit my boost targets and a retune.

 

I have fixed every leak in the system and I honestly have no idea what size pill I have or if I even have one. So I guess I'm going to order a 1mm and a .8mm and see where that gets me.

 

Is it safe to just put one in and test your boost as long as you don't let it go past 18psi? If not how do you go about testing it before you tune it?

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This may or may not apply, however I have 3 friends with STI's from 06-07, all of them tuned for 16-18psi target (by reputable and different tuners). At one point in their life all of them failed to boost over 10psi until after ecu reset via the AP. A few days later the issue would return. No CEL.

 

turned out that a loose up-pipe heat shield was rattling and causing false knock! once one guy figured it out, everyone followed suit and they are all hitting target boost--and living happily ever after into ringland failure zone.

 

goodluck!

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This may or may not apply, however I have 3 friends with STI's from 06-07, all of them tuned for 16-18psi target (by reputable and different tuners). At one point in their life all of them failed to boost over 10psi until after ecu reset via the AP. A few days later the issue would return. No CEL.

 

Thank you for the idea and I thought of that but none of my heat shields are loose. I do have an aluminum skid plate that isn't the most sturdy in the back of it and could possibly cause a case like that but I have not hit really low boost sense I fixed my boost leaks and up pipe leak. My issue now is that I don't get close to target boost until late like its just spooling slow.

 

If the boost cut to 10psi happens again I will try removing my skid plate and see if that changes anything.

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I got in my restrictor pills today and installed the bigger one of the two (1mm) and it immediately shot to 20+ psi and I let off. I'll have to post my log but it hit 18psi at 2800 rpm so it was much batter.

 

I reinstalled the old pill that is obviously bigger than the 1mm and I'm not sure if it was drilled out or if its just a bigger one. I'll be getting it tuned for the new pill sometime soon I hope.

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No kidding you shot up to 20psi. You can't just pop in a different pill and start driving. I still firmly believe something isn't right... I and many other people hit 18PSI in 3rd, by 3KRPM without bouncing off Max WGDC just fine on a VF40 stage 2 setup.

 

What's your LV look like now (post it please) and how many miles are on that LV since you last reset your ECU?

 

When you do these WOT pulls, are you doing them after some driving, so you know that your TMIC isn't heatsoaked?

 

How's your exhaust sounding.... louder than normal? Smell any exhaust up front or anything? I'm wondering if you have a problem like I did with a ton of exhaust gaskets leaking effectively hurting spool.

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Honestly I have checked and checked for leaks and the only exhaust leak I found was on my up pipe. The exhaust sounds great and I drove about 3 miles to the road I did the log on. I feel like maybe I should get the factory pill for my car because I have no idea what the one in it is and maybe go from there. It's around 40° here so I feel like my IC should have been pretty cool.

 

http://i1286.photobucket.com/albums/a606/yfarmeaahka/E0E2B8B0-7785-4E7C-88B2-107BF549C565-12059-0000015D67E722B9_zps2e486471.jpg

 

I haven't reset my ECU sense before the first LV I posted so its been awhile.

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It was on the up stream flange before the o2 sensor and it was pretty big. It leaked from about an inch slit in the flange and when I smoke tested it it had a good little stream of smoke coming out. Those smoke machines don't pressurize barely at all either so that was without pressure.
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  • 4 weeks later...

Alright I finally figured out all my issues...

 

Turns out the restrictor pill was actually bigger than the factory size pill so I replaced that. I found a guy in town that is a Toyota engineer and he knows his way around subaru's because he has built a couple. He has tuned many different kinds of cars but mainly subaru's from what I understand. With the new pill it spools much sooner and is where it should be finally!

 

When I had my car tuned by shamar I had no idea I had a bigger pill size and he never said anything about it from my logs so I never thought anything of it. I also told him I wanted a very safe tune so he apparently set the boost to cut back if the car saw more than 1° of knock correction. Sense I was seeing over 1° that's what was causing my boost to cut off.

 

The guy that tuned it fixed the knock issue and smoothened out the power quite a bit. He also said my fuel was stuck in either open or closed loop, I can't remember, so he's going to find some tables for my car to give me better gas milage.

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