Cabin Fumes Help
 

Hi guys.

Exhaust setup:

-1320 Catless UEL
- High Flow FP
- Custom catback

I am experiencing bad exhaust smells in cabin when driving hard OVER 4k.

Street diving is fine, but driving on the highway is rough, especially merging on from the main road.

Here's what me and my mechanic did to try and trouble shoot:

1. Car was lifted on hoist and revved up to see if we could feel any air pressure at gaskets.

2. Covering exhaust tips on idle to see if air was escaping out else where.

Nothing!

I'm frustrated because this SHOULDNT happen, especially at 120km/h on the highway, but I simply dont have an answer.

I'm hoping someone does...

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Make sure your sound generator tube is attached at all spots tightly. Also try recirculating the air and setting it to feet to see if the smell stops.

Also, your "high flow" front pipe, is it catless?

Mechanic said tube should be ok but hard to verify. In terms of the AC they said smell wasn't coming out from vents although I'm skeptical. My friend who's a technician at Subaru said to take out the headers and put copper silicone on gaskets for a full seal.

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You can block the sound generator tube using the cigarette lighter plug that's in the glovebox. The sound tube entrance is under the glovebox in the footwell/firewall area. I would recommend checking the header flanges to see if they're black on any one side. You'll know there's a leak if it's black

I plugged the sound tube but the smell comes out of no where. Would have heard more sound coming from passenger footwell. Didnt know about the black marks on headers. Really good idea. I hope it works. I hopefully will have an update tmrw at this time

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Update I'm an idiot. Forget we ran air lines through the sound tube.

Anyone else made this mistake, fixed it and found it got rid of horrible smells? https://uploads.tapatalk-cdn.com/202...f9a976d381.jpg

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What?

My sound tube isnt sealed because I'm running air lines through it for my struts. I have the 3p kit from airlift.

Shit! I have no idea how to seal it which still have the lines through.... :/

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Fill the space around the air tube with putty.

Bubba says that bubble gum works good too.


humfrz

Could try running the line through a boot type grommet to see if that deals it enough... or run the lines somewhere else

put your air on recycle. if my car is cold and im sitting there for a while i start to get the smell if not on recycle. no issues when moving

OK so you found where the smell is getting into the car but still have not answered the question of where it is coming from in the first place. There should not be any exhaust fumes under the hood of the car to come through the sound tube even if it is open.

Recycle doesn't work with the defroster setting turned on. It switches over automatically to outside air.

This would piss me off. If there is a problem where it won't seal with regular gaskets there is a potential issue, don't band aid it to fix it. It's not an 85' Toyota.

I would retorque the header fasteners and look for black sooty streaks coming from any exhaust connections. I wonder if you have a warped mating surface.

FIFY

Update:

There was black soot on the gaskets.

My guy said the gaskets aren't that good even though they came with the header.

Hes working on the car now.

Will give update later

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Check the flanges for flatness. Flanges can be warped, or can warp when hot.

Update:

No more smell unless coming to a stop or reversing! (This is expected)

Thanks to everyone that commented.

Mechanic put some gasket sealant on the headers to block, headers to overpipe and overpipe to fp.

Seemed to have worked.

He also plugged the sound tube with silicone.

Looks like this problem is solved.

Thanks 86 fam [emoji2936][emoji2935]https://uploads.tapatalk-cdn.com/202...814f8a3101.jpg

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Update...

Smell vaugely came back into cabin.

If it was originally 7/10 on how strong the smell was, it is now 3/10.

I'm starting to think the A/C MAY have something to do with this.

I also notice the I smell the fumes while driving with my windows down.

Even at 60 + km/h.

Pretty frustrated and annoyed.

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Check the flanges for flatness. Sounds like putting ultra copper on the gaskets didn't work.

I honestly might switch to my oem fp.

I have this stupid fluttering sound other people have when they have the same header as me


They said stock fp gets rid of it.

It should get rid of smell too.

Just no snap crackle and pops :(

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https://www.amazon.com/Remflex-6005-.../dp/B00B2HMF7G

https://www.amazon.com/Remflex-RF16-.../dp/B000TLL7JS

I know the 6005 is correct but double check the 16-000 just to make sure it'll fit (it should). I have a cheap OP with warped flanges and the remflex gaskets sealed it up. Don't overtorque, it only asks for 20 ft. lbs.

Remflex gaskets are excellent. Never bothered to look to see if they made any that fit our cars.

Need to stop trying to fix the symptoms and fix the problem. Fix it right stop throwing bandaids at it.

Update: fumes came back temporarily, but when I changed my cabin filter (it was originally filllltthhhyyy) all smell gone. No fumes no nothing anymore. Wish I didnt sell my fp :((((

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Update. After going back to stock I had no fume smell. Bought the invidia high flow fp and smell is back ONLY when windows are rolled down. Happens when I'm on highway too. Idk how it makes any sense. When the motor is being pushed it gets stronger, but not clue how it gets into the cabin at speeds higher than 40 kmh

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I have this issue as well. Completely striped interior, no HVAC, catless header/fp. I felt like I almost had CO poisoning after driving with the windows down for an hour straight. About to start looking for leaks this week, and we could compare notes.

also, atleast for me, this could be it:

when driving, exhaust fumes get trapped in a turbulance behind the car. with open windows, you get a low pressure condition inside the car = exhaust fumes get sucked inside through the "leaking" trunk gasket.

One month ago I'd laugh at that idea. However you are definitely on to something. After getting a new high flow fp I noticed that I would only smell cabin fumes when windows we down.

This never happened with the same setup on the stock fp.

I read in a GTR forum that others have similar issues, in addition to some mustang owners.

One GTR owner put a hot pizza in his trunk and then he actually smelt pizza in his cabin when he drove with the windows down.

I did the same thing with air fresheners from Little trees last night and same thing happened to me!

I was really happy because I found the issue.

Keep in mind that the 2 Little Tree air fresheners were underneath my trunk floor board and my seats were not folded down either.

Basically as you said, for whatever reason the vacuum is enough to draw in exhaust air into cabin.

For me specifically it is because I am on the airlift 3p kit and you have to run lines through the bottom of your trunk to the rear struts.

Despite putting the OEM rubber sealer over it during install a few months ago, still exhaust gasses pass through.

Going to silicone the shit out of it tonight lol.

Will update later this week

SO HAPPY!!!https://uploads.tapatalk-cdn.com/202...7c2a836328.jpg

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