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Discussion Starter · #21 ·
I am looking at the exhaust diagrams and see the pipe bolted to the turbo also has a cat in it? If that's clogged would I have the low 3-4 lbs boost? And no cel and no smoke or weird noises? That would kinda make sense to me as it would start to build boost then dump it out the wastegate....? Would I hear that? Or am I on the wrong track here? I put my infrared gun on the back cat. Didn't realize this was a cat as well. Looks like a pain to get off.....lol!
 

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No, the wastegate is controlled by induction pressure. Even if there's massive back pressure on exhaust side, as long as engine can spin, the turbo will continue to build pressure. It might not reach boost target, but it won't stop as low as 3psi, that indicates the ecu is actively deciding to bleed pressure.
 

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Discussion Starter · #23 ·
No, the wastegate is controlled by induction pressure. Even if there's massive back pressure on exhaust side, as long as engine can spin, the turbo will continue to build pressure. It might not reach boost target, but it won't stop as low as 3psi, that indicates the ecu is actively deciding to bleed pressure.
Thanks, I have decided this is a very complicated little motor. I've been reading continually and it's very, very hard to find anyone posting this exact issue. So it must not be all that common. I found one post similar and it ended up the guy had clogged cats. I found my old compression tester stuff and the hose end matched an old O2 sensor I have here. I'll try the pressure test as well as the temp test later this morning and report back.
 

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No more complicated than most modern turbo engines, since you are hitting dead ends, it might be worth doing a compression test just to rule that out. Service manual says 200-245psi for healthy engine with max 14psi variation. Test done with fully warmed up engine and gas pedal fully depressed while cranking.
 

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Discussion Starter · #25 ·
No more complicated than most modern turbo engines, since you are hitting dead ends, it might be worth doing a compression test just to rule that out. Service manual says 200-245psi for healthy engine with max 14psi variation. Test done with fully warmed up engine and gas pedal fully depressed while cranking.
Well pressure test showed no restrictions in front cat and temps seemed to be in line with tests I saw online. My grandson got home late last night from work, heads out again tomorrow to Ohio this time. I called a friend who has a cousin with an STI and asked about our local dealers service center. They got a really good review from him so my grandson said we are taking it in. He doesn't want me to spend any more of my vacation week working on his car. So I guess Monday I'll call and schedule getting it in.

We did do two datalogs, one driving normal and one in third from about 3k to 5k but boost started then diminished and went away. He's looking into how to download them and once I have them I will post them up. I did a vacum test at idle on the two hoses under the intake behind the alternator. Both held at 15-16psi. So I'll post the logs up soon as he gets them to me.
 

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Discussion Starter · #26 ·
So my last check was the wastegate actuator. I put a little air to it and it worked great. So I’ve exhausted all the things I can check at this point. I have the logs and will try to put them on here.
 

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Putting air to it just tells you it's not stuck. Doesn't necessarily tell you whether it's controlling pressure correctly. It's still very strange that you don't have any codes, no leaks, DAM at 1 and no other issues.

One thing that might do all this is a bad throttle position sensor. You could put throttle position on the triple meter on dashboard or on accessport and see if throttle actually goes to 100% when you press the gas pedal.
 

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Discussion Starter · #28 ·
Putting air to it just tells you it's not stuck. Doesn't necessarily tell you whether it's controlling pressure correctly. It's still very strange that you don't have any codes, no leaks, DAM at 1 and no other issues.

One thing that might do all this is a bad throttle position sensor. You could put throttle position on the triple meter on dashboard or on accessport and see if throttle actually goes to 100% when you press the gas pedal.
I will do that. I have the logs in my email but can’t figure out how to upload them here. I’ll see if the tps is one of the monitored items listed.
 

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Discussion Starter · #30 ·
Please lmk cause im having the same problem
Will do. I have two logs but I am having a terrible time figuring out how to get them uploaded. My grandson told me to call and schedule it in to the State College Subaru dealer since I have checked so many things with no luck. I will drive it there, it runs ok and the logs show no detonation. So as soon as I know anything I will update this thread. It's on the schedule for Monday. Almost a week left for me to figure it out! Lol!
 

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Maybe one of the mods can comment on which file types are allowed. No offense but most people on these forums would be a bit hesitant to give out email addresses or open unknown files.

Didn't work in what way? Typically you can click here, login to your google account and click on new sheet. From there it works like excel. Copy paste the data in there or import xls/csv file. Then click the blue share button in top right corner, enable link sharing and post the link here.
 

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This appears to be a log while it's idling, speed is zero and throttle position 3.5% for all rows. But I can see all of it so it's just a matter of copying the rest.

Also you can set google sheets to share anonymously if you would like to hide your google username.
 

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Discussion Starter · #40 ·
This appears to be a log while it's idling, speed is zero and throttle position 3.5% for all rows. But I can see all of it so it's just a matter of copying the rest.

Also you can set google sheets to share anonymously if you would like to hide your google username.
Well I'll see if I can get some help tomorrow. I see 2052 lines when I clicked WRX.Datalog....is that only 50 seconds?? Lol. I need some computer lessons.
 
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