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2005 Legacy GT
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3,726 Posts
Discussion Starter #1
Looking for a little help here. I have somewhat recently gone stage 2 + on my LGT with the following parts:

AEM CAI
AVO TMIC
Grimmspeed PnP exhaust manifold (coated)
Grimmspeed Highflow crossover pipe (coated and wrapped)
Grimmspeed UP (coated and wrapped)
Cobb catted DP
Stock CBE
AP v.2 running TA map

My problem is that the car absolutely stinks like exhaust fumes, especially when idling high after a cold start or after I romp on it a bit. The other day after installing the CAI, my friend and I took turns revving it up a bit while having the hood open and sticking our heads in there to listen. While on the test drive, we both felt lightheaded/weak and dizzy. Kinda like I wanted to pass out.

Doing some digging on LGT.com, the used "catted" DP I bought was also used by 2 or 3 other members before me. So its possible the cat has seen such high EGTs for a while that it no longer works.

The three scenarios I can think of causing this are:

1) an exhaust leak somewhere, though I don't hear anything which sound like a leak, and don't notice any black soot near connections. Also holds boost fine (no problem hitting 18.6 a couple days ago).

2) This is normal when going from 3 restrictive stock cats to a high flow system with one HFC.

3) My cat has gone bad/worn out on the DP and I'm rutting catless. The "HFC" has essentially become a resonator.
 

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Administrator
2004 Forester XT Premium 4EAT
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30,105 Posts
If you're IN the car and smell the fumes in the cabin when stationary (i.e. at a red light or in stop and go traffic), you probably have an exhaust leak somewhere. Had that issue some time ago and always had to roll the windows down for ventilation when stopped so I wouldn't pass out... :lol:

I would check for leaks, especially around the downpipe.
 

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Premium Member
2007 XT Sport 5MT
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24,101 Posts
My guess is it's leaking as well.
Did you have to replace the donut gasket between the downpipe and the other catalytic converter? Unless the downpipe had one of those built in donut gaskets, that could be the cause of the leak... or even a bad gasket on the turbo end.

But I'm just guessing out loud here, the LGT might be different from the Foresters.
 

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2005 Legacy GT
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3,726 Posts
Discussion Starter #5
Thanks for the responses. Yeah Duder, we replaced all of them with new OEM gaskets when doing the install, including the donut.

I've checked all the easy to get to connections (manifold to block, x-over to manifold, and manifold to UP) and they all seem fine. I was afraid it may be something closer to the turbo like the UP/DP. (Please not at the UP! :fingers crossed:)
 

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99 UK S-turbo
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8,590 Posts
A 'catted' exhaust without a cat doesn't stink, and you don't want catted or non cat exhaust fumes in the car anyway....

Suspect you have a leak as others have said.

Simon
 

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2007 FSTI and X 6 MT
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22,330 Posts
SD, I ran this on my LGT

perrin catted DP
MR quad tip
sti up pipe
aem cai
ap v2 with tdc tune

My car always smelled badly, really bad. I sold off everything and went back to stock minus the up pipe and it smells fine. I purchased my DP new, and I am though I had NO exhaust leaks as it was checked by 3 different mechanics on different racks. Guess why my car smelled bad and I could not roll down my windows or open my roof?

Small leak on the turbo to DP gasket. Makes no sence as everything was tq to spec, and a new gasket was used.

I will bet that you have a leak in the same area since it sounds about the same as my car
 

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2005 Legacy GT
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3,726 Posts
Discussion Starter #9
You sure its not just the smell of the header wrap/coating on there?
But should that still be stinking like that? The first couple days were real bad with that stuff burning. Smoke was rolling out of the hood scoop at red lights, and I was getting some funny looks.:lol: The exhaust parts were put on in August, the CAI was put on just a few days ago.

Tuned200 said:
SD, I ran this on my LGT

perrin catted DP
MR quad tip
sti up pipe
aem cai
ap v2 with tdc tune

My car always smelled badly, really bad. I sold off everything and went back to stock minus the up pipe and it smells fine. I purchased my DP new, and I am though I had NO exhaust leaks as it was checked by 3 different mechanics on different racks. Guess why my car smelled bad and I could not roll down my windows or open my roof?

Small leak on the turbo to DP gasket. Makes no sence as everything was tq to spec, and a new gasket was used.

I will bet that you have a leak in the same area since it sounds about the same as my car
Yeah, I took off my heatshield and had a look at the DP bolts yesterday, everything seemed tight and no signs of a leak anywhere :confused:. I think I did discover a torn CV boot though, as my arm got greasy as crap from reaching up to the DP bolts from underneath.
 

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2005 Legacy GT
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3,726 Posts
Discussion Starter #11
Brother TSi+WRX was kind enough to link this post: Fuel Smell in cabin. How to fix. - LegacyGT.org

and digging a bit more on LGT.com, it seems quite a few people smell fuel, even when stock. By replacing three cats, it could be just more amplified in my case. I'd rather live with the smell than attempt that fix though.
 

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2016 Outback and WRX CVT
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2,589 Posts
Small leak on the turbo to DP gasket. Makes no sence as everything was tq to spec, and a new gasket was used.
^ I agree, it makes no sense - but I also vote for that one, as something to check. Drop the heat-shield off that area, ScoobyDoobie (I know, it's a pain in the butt :frown:), and see what's up.

Torquing to-spec really doesn't mean much - it could still potentially back-off.

After having the dealership drop-in my new clutch, I spent about 3 weeks heat-cycling and re-tightening the turbo-to-DP area, before it finally settled into place.

I know, it doesn't make sense to me, either, but it's what it does. My pass-manifold -to- UP joint was also problematic in sorta the same fashion, but I was able to address that with just one heat-cycle/re-torque.

It's a mystery. :crazy: I can't believe that every bolt on a part of the engine that heats up would need to be heat-cycled. I mean, what would happen if it's a bolt that you couldn't reach, without major disassembly? :huh:

For me, when I "went Stage II," it took about 2 weeks for the can or two of P'Blaster that I'd sprayed onto the bolts to burn off completely, but that was a pretty distinctive smell.

My guess is that you've either got a leak, or, that DP cat is no longer good any more.

Pop on an aftermarket BOV and see if you're throwing any fireballs on the over-run? :biggrin: That's almost certainly indicative of a cat. that's no longer capable of serving as a cat.
 

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99 UK S-turbo
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Bolts correctly torqued should not need checking....

The correct torque should stretch the bolt to about 2/3's of its elastic limit, so nay change in the nature of the joint due to heat can be accomodated by either the remaining 1/3 or by relaxing back by 1/3's still maintaing a clamp load.

If the bolt took another 1/4 turn it wasn't torqued properly in the first place.

Simon
 

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2016 Outback and WRX CVT
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2,589 Posts
Bolts correctly torqued should not need checking....

The correct torque should stretch the bolt to about 2/3's of its elastic limit, so nay change in the nature of the joint due to heat can be accomodated by either the remaining 1/3 or by relaxing back by 1/3's still maintaing a clamp load.

If the bolt took another 1/4 turn it wasn't torqued properly in the first place.

Simon
^ This may be true in theory, but in practice, in the real world, on our various exhaust components, it's far from the case.

I don't know about whether or not the tech(s) who worked on my vehicle (clutch/fly job) properly torqued the turbo-to-DP bolts the first time, from which they backed-off significantly, but I *know* that I did, when I went in for my re-check after they did their work, and yet it still backed off.

Similarly, I *_know_* I followed spec, when I "went Stage II" now some 4+ years ago - I had the garage and driveway set up the way I would one of my surgeries, and those who either helped or otherwise stopped by to chat that day all marveled at the way everything, down to the last bolt, had been labeled and cross-referenced.

And this is what I don't understand....

What you'd proposed should be the way it works - heck, it works to put the engine together, and like I said, I don't understand why we'd need to re-torque after heat-cycling, given that our engines aren't literally falling apart. :crazy::biggrin:

But why do our exhaust components always seem to be funny...I honestly don't get it..... :shrug: Virtually every Subaru community Forum have posts upon posts of such problems, even those who used brand new hardware (for some of my "Stage II" installs, new hardware was used, too - and there was no noticeable difference between whether or not it was re-used hardware that backed off [which would make sense] or new [which did not make sense]). Dunno. :shrug:


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I did look at the DP->turbo connection and there was no soot or sign of a leak. One DP bolt did crank about a 1/4 turn though
^ Dangit, there goes that theory. :frown:
 

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2016 Outback and WRX CVT
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2,589 Posts
^ You need more tools! Must get enough tools to do the job right, that's always been my excuse to the wifey, so that I can accumulate more stuff! :woohoo:

Man, forget the monkey. If only I had access to that 3000-lb. gorilla that SoA uses in their Indiana plant to torque some of the bolts, I'd be plenty happy. :biggrin:
 
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