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2G Overboosting help

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Dawson159

5+ Year Contributor
164
16
Nov 13, 2017
Billings, Montana
so yesterday was the first day I got to drive my eclipse more than 2 miles st once and I noticed my boost gauge was reading 25psi and I was like oh shit so I pulled over and me and my friend tuned down my manual boost controller all the way down it read 12psi which made sense because 10psi is stock and 2psi is added when u remove the boost solenoid?( correct if I’m wrong) well I drive it for about 2 hours just happy that I can finally drive it then as the night went on the car started performing worse and worse so we checked the boost gauge again (it was night time and the lights aren’t wired in yet) and I was hitting 25psi again so we thought that maybe the controller turns itself up but it was still turned all the way down so I looked it up and I’m pretty sure I have boost creep because I have a 3inch turboback exhaust which is probably causing it. I have a freshly rebuilt t25 turbo in it and I don’t wnna ruin it but I also don’t want to drop the turbo to make the wastegate bigger so I started researching and in my chilton manual there is a diagram of the turbo and there is a little hole in the turbo next to the intake (I’ll take a picture) that is just open and the picture in the chilton says it T’s off of the line that goes into the wastegate and that line is the manual boost controller. So I’m totally lost rn:aha: is there a vacuum line issue or is my wastegate just not big enough and I’m going to have to drop the turbo I’m not very mechanicaly inclined and this turbo wastegate stuff is kind of confusing to me so what do u guys think is the problem

Thanks in advance if u read that wall of words:dsm:
 

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so yesterday was the first day I got to drive my eclipse more than 2 miles at once and I noticed my boost gauge was reading 25psi and I was like oh shit so I pulled over and me and my friend tuned down my manual boost controller all the way down it read 12psi which made sense because 10psi is stock and 2psi is added when u remove the boost solenoid?( correct if I’m wrong) well I drive it for about 2 hours just happy that I can finally drive it then as the night went on the car started performing worse and worse so we checked the boost gauge again (it was night time and the lights aren’t wired in yet) and I was hitting 25psi again so we thought that maybe the controller turns itself up but it was still turned all the way down so I looked it up and I’m pretty sure I have boost creep because I have a 3inch turboback exhaust which is probably causing it. I have a freshly rebuilt t25 turbo in it and I don’t wnna ruin it but I also don’t want to drop the turbo to make the wastegate bigger so I started researching and in my chilton manual there is a diagram of the turbo and there is a little hole in the turbo next to the intake (I’ll take a picture) that is just open and the picture in the chilton says it T’s off of the line that goes into the wastegate and that line is the manual boost controller. So I’m totally lost rn:aha: is there a vacuum line issue or is my wastegate just not big enough and I’m going to have to drop the turbo I’m not very mechanicaly inclined and this turbo wastegate stuff is kind of confusing to me so what do u guys think is the problem

Thanks in advance if u read that wall of words:dsm:
 
If it's open, you have boost leak. That hole might be for boost source. I'd do a boost leak test first.
There is air coming out of it when I do a boost leak test, how do I fix it and could that be why it’s overboosting?
 
There is air coming out of it when I do a boost leak test, how do I fix it and could that be why it’s overboosting?


I am not entirely sure what hole you are talking about. A picture would help a ton.
 
Looks like boost source. Can't see behind it. If it's on the housing, odds are it is and you can run that directly to your wastegate and it SHOULD run on spring pressure. If it still overboosts, you may have to port under the flapper if restriction is causing the overboost.

I'm having the same issue. Will prob take off turbo next oil change.
 
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Yeah that needs to be hooked to your boost controller. It looks like a vacuum line came off. Trace the lines from the boost controller and see where they go. If one is disconnected, that is where it should go to. If both lines to the boost controller are hooked to something, tell / show us what. Because it is more than likely wrong.
 
That hole is suppose to go to the wastegate for boost

you have tons of hoses installed incorrectly, so there's no way you're making even 5psi

If the boost source line is not hooked up, which it does not appear to be, then the turbo will just make as much boost as it wants because the wastegate is not ever opening. It will make way over 5 psi.
 
Yeah that needs to be hooked to your boost controller. It looks like a vacuum line came off. Trace the lines from the boost controller and see where they go. If one is disconnected, that is where it should go to. If both lines to the boost controller are hooked to something, tell / show us what. Because it is more than likely wrong.
One of the lines cane off I found it hidden under the controller
 
Be sure to put a small clamp of some sort on it to prevent it from happening in the future. Even a zip tie would be better than nothing.
I put it back together and it’s creeping again :( I guess im gonna have to drop the turbo and port the wastegate :banghead:
 
Here is the thing, if the car was getting boost creep from the 3in downpipe and the wastegate needing ported, it would do it every single time since you put the downpipe on. Correct me if im wrong but didnt you say that you were able to get it to run 12psi for a few hours?

Also is it actually "creeping" to 25psi or is it "spiking"? They are two different things.
 
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Here is the thing, if the car was getting boost creep from the 3in downpipe and the wastegate needing ported, it would do it every single time since you put the downpipe on. Correct me if im wrong but didnt you say that you were able to get it to run 12psi for a few hours?
Yah it runs at 12psi and it slowly creeps up to 15psi then up to 25psi. What do U think it is? Idk if it’s coincidence but it seems to go up every time I turn it off and on and the boost controller is turned all the way down but it still hits 15psi:aha:
 
Also is it actually "creeping" to 25psi or is it "spiking"? They are two different things.
It hits 3k rpms and it goes to 25psi right away then I let off because it hits so hard and it’s hard to control so should I see if it stays that high all the way to almost redline?
 
It hits 3k rpms and it goes to 25psi right away then I let off because it hits so hard and it’s hard to control so should I see if it stays that high all the way to almost redline?

Noooo. Do not do that. Im assuming that your car is not tuned for that and could blow your engine. First off, if it is shooting up to 25psi at 3k or so that is boost spike, not creep. But what you described in post #17 is boost creep. So which one is actually happening?

Second, show us pictures of where all the vacuum lines for the boost controller are routed so we can tell you if its hooked up properly. It should be something like this

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If this is all hooked up right, then I would take the actuator arm off of the wastegate flapper and go do a pull. If you are still getting boost creep, then you need to port the wastegate hole or get a more restrictive exhaust. If it goes away, then there is another issue at hand.
 
Noooo. Do not do that. Im assuming that your car is not tuned for that and could blow your engine. First off, if it is shooting up to 25psi at 3k or so that is boost spike, not creep. But what you described in post #17 is boost creep. So which one is actually happening?

Second, show us pictures of where all the vacuum lines for the boost controller are routed so we can tell you if its hooked up properly. It should be something like this

You must be logged in to view this image or video.



If this is all hooked up right, then I would take the actuator arm off of the wastegate flapper and go do a pull. If you are still getting boost creep, then you need to port the wastegate hole or get a more restrictive exhaust. If it goes away, then there is another issue at hand.
Does it matter if the wastegate actuator line is Hooked to the long end of the MBC instead of the side because of it does then they’re backwards
 
Yes it most definitely matters. What brand boost controller do you have?
Hallman boost controller and I was driving home from my friends house and I did a pull to see if it’s spike or creep at 3/4 throttle bcause it hasn’t creeped to 25 yet I pulled all the way to about 6k rpms and it stayed at 15psi so I’m pretty sure it’s creep but after the pull the car started acting really weird and wouldn’t go above 2k rpms and it got progressively worse so I pulled over and plugged my maf back in(it was running better without it plugged in) and it ran even worse so I unplugged it and got it home going 10mph if I tried to go above 1500 rpms it would jerk super bad this is probly a different issues but it’s super annoying and frustrating. My friend said it’s like my injectors we maxing out?? I have a mess on my hands :toobad:
 
With the hallman it needs to be hooked up according to my picture above. If it is backwards then you have an issue. So fix that if it needs it.
You should not be doing any pulls with your MAF unhooked. You can seriously hurt your engine. Im surprised the car even made boost without it hooked up. Did you blow an intercooler pipe maybe?
 
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