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Old 02-05-2019, 03:15 PM   #1
putrio
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Member#: 494757
Join Date: Dec 2018
Chapter/Region: MWSOC
Location: Cincinnati, OH
Vehicle:
2011 STI Hatch
Black

Default What is this noise?

Hi All,

So after what seemed at the time like an endless string of setbacks....I have my engine back in my car. It's the street spec pro from Rallispec. I modified the ECU map I was using prior to the engine to limit revs to 5500 (which is the max the break-in process uses) and also to limit boost to spring pressure. I also removed a crapton of check engine lights as I removed the secondary air pump, did a TGV delete, and some other things. That being said...The break-in process from Rallispec says to essentially start the car and let it high-idle until the radiator fans come on.

WHAT IS THIS NOISE!?! The car had been on for about 6 minutes at that point, and the coolant temperature was up to about 166 degrees.


It seems to be coming from under the intercooler, but the car is in neutral with the e-brake on. It's pretty loud, enough so that even though I was expecting it I almost dropped my phone when it happened. I have yet to put it into gear because the noise worries me. Before I started videoing it made the noise a few times within 10 seconds or so.

Also, my idle is really odd. It starts off extremely low, like 450rpm, and is really unsteady, dipping down to 300 and seeming to almost stall, then revving itself up to 1500, and then after a few minutes stabilizing at around 1000.
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Old 02-06-2019, 04:30 PM   #2
putrio
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Member#: 494757
Join Date: Dec 2018
Chapter/Region: MWSOC
Location: Cincinnati, OH
Vehicle:
2011 STI Hatch
Black

Default

Nobody has any ideas? Please?! This is the first time I've ever broken in an engine, and I'm starting to think *maybe* the noise is just because it's coming up to temperature? It happens at about 165 degrees...

Also I think the really rough idle is because of the TGV deletes...
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Old 02-11-2019, 02:49 PM   #3
Bamofo
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Member#: 159743
Join Date: Sep 2007
Location: Plymouth Ma
Vehicle:
07 STI Limited
TurboMike Tuned 2.35

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sounds like your turbo.. but what does romraider say the problem is?
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Old 02-20-2019, 01:06 PM   #4
putrio
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Location: Cincinnati, OH
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2011 STI Hatch
Black

Default

Quote:
Originally Posted by Bamofo View Post
sounds like your turbo.. but what does romraider say the problem is?
Hmph, didn't subscribe to my own thread. I don't have romraider, however according to my AP logs, the front o2 is reading extremely lean, causing the car to apply max correction to fueling, which is causing it to run so rich gas is pooling in the exhaust tips.

How would the turbo make a cracking sound? Is something breaking? Broken? Is it the excess fuel igniting outside of the engine?

From another thread of mine, my next steps are to fix some leaks I have and relog, but I'd love to know what that sound is. It only does it at idle, not when holding the RPMs above idle.
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Old 02-28-2019, 10:33 PM   #5
putrio
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Member#: 494757
Join Date: Dec 2018
Chapter/Region: MWSOC
Location: Cincinnati, OH
Vehicle:
2011 STI Hatch
Black

Default

Update - there was a hose I thought was connected (I even moved the hose clamp into position) that was not, directly underneath the throttle body. The cracking noise was due to the car making the A/F so rich, fuel was getting through the turbo and igniting somewhere, coming out that vacuum hose. Connected everything, and car is running perfectly now. Haven't taken it on the road yet due to power steering problems, but the idle is smooth as silk and goes right back to normal idle when abruptly letting off the throttle. Thanks for the help everyone.
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