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  1. #1

    Default New Catalytic Converter Question

    I just replaced the catalytic converters on my 2002 Chevrolet Suburban with the 5.3L Flex Fuel engine ("Z" engine). I installed a Walker 50511 catalytic converter assembly. It went on very easily and fit perfectly. I also replaced all four of the oxygen sensors with OEM Denso sensors.

    I put the vehicle on a logging scanner and scanned all four oxygen sensors. The upstream sensors switched back and fourth between the normal extreems with the expected rapidity. The downstream oxygen sensors stayed mainly at one extreme. One was at .8 volts and the other around 0 volts. The downstream oxygen sensors' voltages would change when a dramatic event occurred, such as hard acceleration, but would eventually go to one of the extremes. No codes are pending and the Check Engine light is not lit.

    I only have about 20 miles on the new converters. Should it take some time for the new catalytic convers and oxygen sensors to "break-in" ?

  2. #2
    Sr. Engineer
    Join Date
    Oct 2010
    Indianapolis, In


    Don't know what voltage range they have while operating so it may or may not be a big deal, sorry no help there. Since they are new, would it be hard to swap them left to right and see if the difference follows the sensor?
    2000 GMC YUKON SLT, 5.3L tow pkg, G80 rear/w 3.73 gear

  3. #3


    Good point. It's realtivelely easy to get to the back sensors to swap them, particularly since they are not siezed in place yet.

    I've also sent an inquiry to the manufacturer of the catalytic converters to see what they have to say on this matter.

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