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Old 07-16-2013, 10:22 AM   #1
juice91si
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Default low boost

I have an 06 Sti, I bought it and it was already stage 2.

I've had it for 6 months now, and am now having my first issue.


If this is not the right forum, please move my thread.


Three weeks ago I noticed by boost was only hitting 8 psi, when normally its about 18.

By the time I got home, and took it out for another drive, it was fine again. I figured it was nothing, until it started happening again. Over the last few days, it's gone from intermittent, to all the time.

I disconnected the battery to see if it it would re-learn the map, and it worked, 18 psi no problem. Shut the car off, turned it back on, and its back at 8.

Over the last couple days, I have been disconnecting the battery to see if it solves the issue and fixes it (I know this won't work), but it does temporarily until I turn the car off and turn it on, back to 8 psi.

Any ideas? Is there a sensor, or the boost solenoid or something that is causing this issue? It seems like a electronic issue because it works fine after I disconnect the battery...Help!

I've searched and no one seems to update their threads with fixes or solutions, just dead ends, has anyone figured this issue out?
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Old 07-16-2013, 10:33 AM   #2
mbhammerbro
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Does the car feel like its only hitting 8 psi? How are you reading what boost your hitting?
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Old 07-16-2013, 10:40 AM   #3
tuzzio
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Unhook the boost control solenoid and run a vacuum line from your waste gate right to the compressor housing. Let us know what you see for boost with that.
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Old 07-16-2013, 11:28 AM   #4
BApat
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Do you have an Accessport or any way to log? If so, that would be a good place to start too. I don't mean to scare you but it sounds like your car is running in safety mode to protect itself. I have seen this issue with cars which have blown ring langs. I'm not saying that is definitely it but this is a symptom. If you have an AP, log the DOM parameter. If it is at 0 insead of 1 then you have some issues going on.
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Old 07-16-2013, 11:52 AM   #5
juice91si
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Quote:
Originally Posted by mbhammerbro View Post
Does the car feel like its only hitting 8 psi? How are you reading what boost your hitting?

Yup, it is definitely hitting 8psi, you can feel its slow as balls and my boost gauge reads 8psi.
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Old 07-16-2013, 11:54 AM   #6
juice91si
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Quote:
Originally Posted by tuzzio View Post
Unhook the boost control solenoid and run a vacuum line from your waste gate right to the compressor housing. Let us know what you see for boost with that.

I'll give this a shot...but what does that tell me? If it overboosts, or does the same thing, what is this testing? the boost solenoid?
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Old 07-16-2013, 11:55 AM   #7
juice91si
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Quote:
Originally Posted by BApat View Post
Do you have an Accessport or any way to log? If so, that would be a good place to start too. I don't mean to scare you but it sounds like your car is running in safety mode to protect itself. I have seen this issue with cars which have blown ring langs. I'm not saying that is definitely it but this is a symptom. If you have an AP, log the DOM parameter. If it is at 0 insead of 1 then you have some issues going on.
I do not have AP, its tuned on openECU I think..I have the tactrix thingy, but no laptop..I guess I need to buy a laptop and learn to datalog...


Has no one experienced and fixed this issue? Hopefully someone that has can chime in.
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Old 07-16-2013, 12:35 PM   #8
mbhammerbro
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Sorry, super hard to diagnose without logs.
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Old 07-16-2013, 01:47 PM   #9
Cathexis
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Quote:
Originally Posted by juice91si View Post

I do not have AP, its tuned on openECU I think..I have the tactrix thingy, but no laptop..I guess I need to buy a laptop and learn to datalog...

Has no one experienced and fixed this issue? Hopefully someone that has can chime in.
Too many posibilities. You can start by checking vacuum lines, ect. From a visual standpoint. Anything else and it will need diagnosis. One way is logging. The other gets pricey at 85+ an hour.
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Old 07-16-2013, 03:14 PM   #10
tuzzio
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Quote:
Originally Posted by juice91si View Post

I'll give this a shot...but what does that tell me? If it overboosts, or does the same thing, what is this testing? the boost solenoid?
This is testing the waste gate. I believe that 11psi is what your stock wastegate is set for. It's eliminating all the electronics as predators. If you're still getting 8psi, you could have a bad wastegate or turbo.
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Old 07-16-2013, 03:28 PM   #11
07STifastashell
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Damn... Wish you had an AP to log. Any knocking? Everyone else listed more common issues that are associated with low boost, but it could be as serious as spun bearing or cracked piston without any other information present. If you are knocking at all, keep out of boost or else your ecu is going to keep pulling timing.
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Old 07-16-2013, 08:41 PM   #12
juice91si
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Quote:
Originally Posted by 07STifastashell View Post
Damn... Wish you had an AP to log. Any knocking? Everyone else listed more common issues that are associated with low boost, but it could be as serious as spun bearing or cracked piston without any other information present. If you are knocking at all, keep out of boost or else your ecu is going to keep pulling timing.

the car runs beautifully, just low boost. I'm going to see if I can buy a laptop tonight or tomorrow so I can learn to log....I don't hear any knocking, I went over a bridge so I can hear the engine sound a biut better from the walls of the bridge, but no knocking can be heard.
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Old 07-16-2013, 08:43 PM   #13
juice91si
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Quote:
Originally Posted by tuzzio View Post
This is testing the waste gate. I believe that 11psi is what your stock wastegate is set for. It's eliminating all the electronics as predators. If you're still getting 8psi, you could have a bad wastegate or turbo.

IF the wastegate was bad, can I just block it off with the grimmspeed plate? and go EWG?

Cuz I have the GS up pipe, tial 38mm and the GS block off plate for the WG sitting in my living room.
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Old 07-16-2013, 10:10 PM   #14
juice91si
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I got a laptop and have romraider logger installed, what parameters should i log?
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Old 07-17-2013, 10:38 AM   #15
juice91si
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Car is running like normal again. Hits boost no problem, I did not disconnect the battery, it just all of a sudden went back to normal. I anticipate the issue happening again, I will attempt to datalog tonight.
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Old 07-17-2013, 11:43 AM   #16
tuzzio
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Yes. EWGs are a blessing.
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Old 07-23-2013, 01:28 AM   #17
juice91si
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https://docs.google.com/file/d/0B7jo...it?usp=sharing

here is my log, i didnt redline it, and now that i figured out how to log, are there better parameters to log to try and figure out my problem?
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Old 07-23-2013, 10:06 AM   #18
juice91si
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WHat is stock boost pressure? what is it in limp mode?

If the car is in limp mode, how the hell do I figure out why if there are no CELs?

Also, it is not a vacuum line, or boost leak, I can simply disoconnect the battery and it boost up to about 18-19psi no problem...
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Old 07-25-2013, 09:14 AM   #19
juice91si
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I tried datalogging again last night, and only had time for a quick run and my gf didn't hit f1 correctly...UGH.

Either way, it was pinging like hell...then it went to limp mode....

ANY IDEAS?? I looked at the max values and it hit 18.45 psi.

It seems that the car recognizes pinging and goes into limp mode, I'll try again tonight I guess...
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Old 07-25-2013, 10:43 AM   #20
Andrewxxcarlson
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Quote:
Originally Posted by juice91si View Post
I tried datalogging again last night, and only had time for a quick run and my gf didn't hit f1 correctly...UGH.

Either way, it was pinging like hell...then it went to limp mode....

ANY IDEAS?? I looked at the max values and it hit 18.45 psi.

It seems that the car recognizes pinging and goes into limp mode, I'll try again tonight I guess...
Lolol get a new gf, mine knows how to completely run romraider (;
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Old 07-25-2013, 11:25 AM   #21
juice91si
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Well, she's good in other ways
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Old 08-08-2013, 01:17 PM   #22
juice91si
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Little update.

Looks like the car went into limp mode because of excessive knock to protect itself. I cleaned the intake filter (COBB) and replaced the spark plugs and cleaned the MAF and it has stopped going into limp mode.

Now that I do not have the boost issue, I've been trying to figure out why it is knocking. A local tuner here said my mass airflow is only about 230 g/s and it should be 260ish.
He suggested I try a buddy's MAF and re-log it. I did, and it showed 256 g/s and a lot less knock, in fact none at all in my latest log.

Hopefully this is a problem solved...Now I just have to fork over 500 bucks for a new MAF!
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Old 08-08-2013, 01:30 PM   #23
Dillinja666
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www.rockauto.com has MAF's for 135 bucks...

Last edited by Dillinja666; 08-08-2013 at 01:36 PM.
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Old 08-21-2013, 02:51 PM   #24
juice91si
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Small update. I got a used maf, and the car feels totally different. I hit 270 g/s and no more limp mode. I still need to log it properly but ive been ridiculously busy. I think the problem is solved though.
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