1. Attachments are working again! Check out this thread for more details and to report any other bugs.

exhaust smell in cabin

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priusmanneedhelp, May 21, 2022.

  1. priusmanneedhelp

    priusmanneedhelp Junior Member

    Joined:
    Oct 11, 2020
    26
    0
    0
    Location:
    Arizona
    Vehicle:
    2005 Prius
    Model:
    ----USA----
    Hello. Previous owners replaced the cat and welded it on poorly. Left an exhaust leak that I later fixed to pass emissions. The smell still remains in the cabin and I still have the p0420 code.

    Can a bad cat cause an exhaust smell to leak into cabin?

    Ive checked all up and down the exhaust system and I find no leaks. None at the manifold either.

    Is it time to bite the bullet and get a new cat?

    P.S I have also replaced the oxygen sensor just to be sure but the issue remains.

    thanks
     
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,463
    8,377
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    There should never be exhaust smell in the car, that's kinda dangerous. How did you pass emissions with p0420? That should give you a check engine light
     
  3. priusmanneedhelp

    priusmanneedhelp Junior Member

    Joined:
    Oct 11, 2020
    26
    0
    0
    Location:
    Arizona
    Vehicle:
    2005 Prius
    Model:
    ----USA----
    Sorry if I worded that weird but I'm trying to pass emissions right now. Def have a check engine light. Its a slight exhaust smell when Im driving. seems to go away when the heater is on. The smell lessened when I repaired the exhaust leak on the poor weld.

    Would a bad cat cause this smell in the cabin?
     
  4. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,463
    8,377
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    A bad weld would only make the exhaust really loud, the gases should not get into the cabin.
     
  5. priusmanneedhelp

    priusmanneedhelp Junior Member

    Joined:
    Oct 11, 2020
    26
    0
    0
    Location:
    Arizona
    Vehicle:
    2005 Prius
    Model:
    ----USA----
    wasn't ever really loud. Wasn't a huge leak but was def leaking when I did the soapy water test. Fixed it with one of those jb weld exhaust tapes. What would cause exhaust smell in the cabin?
     
  6. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,463
    8,377
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    I don't know how exhaust can get inside the car, maybe if the mixture was too rich. The oxygen sensor is oem right?? Denso? I've bought cheap aftermarket Catalytic converters, not all of them work. You'll still get a check engine light from the cheap replacements.
     
  7. priusmanneedhelp

    priusmanneedhelp Junior Member

    Joined:
    Oct 11, 2020
    26
    0
    0
    Location:
    Arizona
    Vehicle:
    2005 Prius
    Model:
    ----USA----

    yup oem denso.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,861
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    could it be in the engine bay, and coming in through hvac?
     
  9. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    1,329
    404
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    The previous owners replaced it because why? Stolen? Sometimes the thieves are not very bright and make cuts in the wrong places. Maybe not even all the way through a pipe, just through the wall. Treat it like any other exhaust leak problem. With the car up on jacks spray along the exhaust with soap water while a helper blows air into the tailpipe with a leaf blower, and like for bubbles.

    For whatever its worth, my son's POS RV had these issues and it was leaking at every junction where two pipes were joined with a gasket and some bolts. It was also leaking at the exhaust manifold due to multiple broken bolts there.
     
  10. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    You probably either have the wrong donut inthe header connection or you reused the oem donut and it’s damaged.

    Take it to a muffler shop.
     
    tangerino likes this.