Exhaust in cabin :(

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by maleko, Nov 15, 2024.

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  1. maleko

    maleko Member

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    My catalytic clogged again after less than 1 year since the last time I scraped and washed it "good enough"... I decided to completely gut it this time around, which fixed the power and back pressure issues but introduced significant exhaust fumes in cabin.

    I quickly replaced both donut gaskets with Toyota OEM brand new, and removed the exhaust manifold, pressure tested it to make sure it didn't have any cracks or leaks, then replaced the exhaust manifold gasket with a brand new FelPro gasket.

    Unfortunately, I am still getting the same, significant exhaust fumes in cabin. No amount of of riding with the windows down helps either. I'm beginning to wonder if the donut gaskets require a certain amount of backpressure to function?

    I am planning to soap test it tomorrow afternoon and see where the leaks might be coming from.... but I have a few theories.

    Currently debating between throwing a cheap $100 aftermarket cat on it versus welding up a single piece straight pipe and keeping the extra power.
     
    #1 maleko, Nov 15, 2024
  2. Tombukt2

    Tombukt2 Senior Member

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    Well I have the same thing done to an '09 here in Orange county North Carolina and my cat have been cut off not gutted and a pipe benefited to replace the cats to where it used to flange and bolt to the cat back is now welded The O2 sensor and bung are still in place and that's that I get no anything in the car exhaust that is I have an '05 that I put a cheap aftermarket converter on I'm not even sure why I did that to see if the light would go out It did not and the donut gaskets were really cheap not Toyota this springs and nuts that are supposed to hold the converter on to the exhaust manifold we're not correct sized so I use the originals with their donut and the gasket at the cat back portion was reused all bolted up car driven for a few months not a leak anywhere nothing coming in the car so I'm not sure how you've done this I don't think the exhaust donuts require any back pressure I don't think that would help them stay sealed higher back pressure might help us push against the springs on the connection at the manifold in the course do nothing or the regular gaskets and bolts are I can get exhaust smell in the car if I remove one of the plugs in the spare tire well but generally that's at idling moving car not so much.
     
    #2 Tombukt2, Nov 15, 2024
  3. maleko

    maleko Member

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    my problem is fumes when moving more so than idling. riding with windows down doesn't help, almost makes it worse.

    I have a feeling its backdraft sucking exhaust in through my leaky rear hatch seal.

    orrrr...

    I might just straight pipe it with a bosozuku style blast pipe,

    upload_2024-11-17_6-27-46.jpeg
     
    #3 maleko, Nov 17, 2024
  4. Tombukt2

    Tombukt2 Senior Member

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    You should be able to sit in hatch area on a board and get idea how it's getting in . Notice no cutout in rear bumper like most cars maybe a hint a small extension maybe in order. They're are very nice non obnoxious looking things .
     
    #4 Tombukt2, Nov 17, 2024
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