04 Lexus LS 430 Bank 2 Cat Efficiency only 113K

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  • Witsend
    Banned
    • Nov 2012
    • 2942

    04 Lexus LS 430 Bank 2 Cat Efficiency only 113K

    Bank 2 Very limited downstream O2 activity going on ,Hoping the muffler cement and a large hose clamp around the outer diameter of the Y-pipe flange to Bank 2 upstream Cat will seal a small gap exhaust leak where the flanges meet ,that may have warped or eroded apart at the bottom of y pipe flange meeting the flange of $1100 upstream cat. The tiny leak is just upstream of the downstream monitor O2. I originally planned to quick swap the 2 downstream O2 sensor that are the same part numbers before changing an O2 or cat, But just to access the O2 connectors under the vehicle carpeting would be a couple hours shot in the @ss. There are Pids that show the internal Cat temps are pretty close to one another, If I recall over 800 degrees F just idling for 10 minutes after a cold start, and freeze frame data both sides were like 1200 degrees F within 10 degrees of each other. When external temps of cats checked with a cheap HF infrared laser thermometer both read about 385F -400F. Hoping to see more downstream O2 activity with the flange leak sealed.
    Update: Drove it around completed all but the evap monitor ran it through the test lane, must have just been that little exhaust leak between the gap of the 2 mating flanges. Glad I didn't change an o2 or a Cat. the clamp around the flanges with the muffler cement should defer a visit to a Mexican Muffler shop for awhile.
    Last edited by Witsend; 04-06-2015, 09:34 AM.
  • Haki
    Junior Member
    • Mar 2015
    • 4

    #2
    Originally posted by Witsend
    Bank 2 Very limited downstream O2 activity going on ,Hoping the muffler cement and a large hose clamp around the outer diameter of the Y-pipe flange to Bank 2 upstream Cat will seal a small gap exhaust leak where the flanges meet ,that may have warped or eroded apart at the bottom of y pipe flange meeting the flange of $1100 upstream cat. The tiny leak is just upstream of the downstream monitor O2. I originally planned to quick swap the 2 downstream O2 sensor that are the same part numbers before changing an O2 or cat, But just to access the O2 connectors under the vehicle carpeting would be a couple hours shot in the @ss. There are Pids that show the internal Cat temps are pretty close to one another, If I recall over 800 degrees F just idling for 10 minutes after a cold start, and freeze frame data both sides were like 1200 degrees F within 10 degrees of each other. When external temps of cats checked with a cheap HF infrared laser thermometer both read about 385F -400F. Hoping to see more downstream O2 activity with the flange leak sealed.
    Update: Drove it around completed all but the evap monitor ran it through the test lane, must have just been that little exhaust leak between the gap of the 2 mating flanges. Glad I didn't change an o2 or a Cat. the clamp around the flanges with the muffler cement should defer a visit to a Mexican Muffler shop for awhile.
    Do you have any scan data to share? .VSM files

    Comment

    • Witsend
      Banned
      • Nov 2012
      • 2942

      #3
      Do you have any scan data to share? .VSM files
      Just a previous screen save of the P0430 a few weeks earlier before my friend ran a gallon of lacquer thinner through a half a tank of gas.The p0430 Code came back before he got home . He had his son clear the code with his code scanner but it came back. I told him the Bank 2 downstream sensor seemed pretty dead. Think it was caused by a small exhaust leak. I drove it and took a photo of Pids the PCM believes the temperature is, but I don't know the theory behind how it works.
      Attached Files

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      • Haki
        Junior Member
        • Mar 2015
        • 4

        #4
        I wanted to see the graphed rear o2 sensors.

        Comment

        • Crusty
          Senior Member
          • Dec 2007
          • 2450

          #5
          Originally posted by Haki
          I wanted to see the graphed rear o2 sensors.
          I would want to see ALL FOUR oxygen sensors and short term and long term fuel trims. (graphs)
          Two rear O2 sensors by themselves won't tell much.

          Comment

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