Exhaust Leak Question
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Joined: Jul 2015
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From: Chicago, IL
Exhaust Leak Question
Hello!
Long time reader, first time poster.
I think I may have an exhaust leak. I've been researching the issue like crazy, but there hasn't been an article/post with my specific question/fact pattern.
I have a full AMS catted exhaust system. During installation one of the bolts on the downpipe near the turbo broke. Given time constraints the shop did not fix it. It wasn't leaking and they were confident it would remain sealed, so they told me to just keep an eye on it.
Every now and then on a cold start I can smell exhaust gas. It goes away after the initial startup and I can't smell anything at all on WOT. During Idle my AFR gauge remains within the 14.5 - 14.8 range and on WOT I hover around the 11.5 sweet spot with no knock at 25-26PSI.
This is the most heavily modified car I've ever owned. Usually I stop after a cat-back and tune, but my Evo has all the basic bolt-on's. Am I smelling a little exhaust at startup because I have a massive downpipe that's just flowing more exhaust out by design?
If I had a leak wouldn't I be able to smell it all the time? Also, wouldn't my AFR read super lean and I'd be unable to hit target boost or have some knock? Before I bought the Evo I had a 2013 STi and it broke constantly. It's made me a little neurotic.
Long time reader, first time poster.
I think I may have an exhaust leak. I've been researching the issue like crazy, but there hasn't been an article/post with my specific question/fact pattern.
I have a full AMS catted exhaust system. During installation one of the bolts on the downpipe near the turbo broke. Given time constraints the shop did not fix it. It wasn't leaking and they were confident it would remain sealed, so they told me to just keep an eye on it.
Every now and then on a cold start I can smell exhaust gas. It goes away after the initial startup and I can't smell anything at all on WOT. During Idle my AFR gauge remains within the 14.5 - 14.8 range and on WOT I hover around the 11.5 sweet spot with no knock at 25-26PSI.
This is the most heavily modified car I've ever owned. Usually I stop after a cat-back and tune, but my Evo has all the basic bolt-on's. Am I smelling a little exhaust at startup because I have a massive downpipe that's just flowing more exhaust out by design?
If I had a leak wouldn't I be able to smell it all the time? Also, wouldn't my AFR read super lean and I'd be unable to hit target boost or have some knock? Before I bought the Evo I had a 2013 STi and it broke constantly. It's made me a little neurotic.
Last edited by moogatwo; Jul 2, 2015 at 10:13 AM.
Evolved Member
Joined: Feb 2012
Posts: 1,253
Likes: 21
From: Ofallon, MO
hmmm well if there is a broken bolt it would be safe to say you have a exhaust leak most likely the only way you would know is if you got around there with a flash light then you can check and see if there is any black soot where the broken bolt is where exhaust is leaking out. As far as it hurting your tune ... i dont really know.. sry
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Joined: Sep 2013
Posts: 14
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From: nj
I'd go to a muffler shop and have them inspect it
Lol i had the exact same thing happen to Me. I didn't bother replacing the bolt that snapped because it really doesn't make a difference. That one bolt will not affect the seal dramatically enough to cause any leaks. My car is on e85 and it's a full bolt on evo x, no issues. I would check to be sure tho. Take the heat shield off if it's on the car and look. Takes maybe 10 mins
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