O2 sensor on chevy truck

Discussion in 'Chevy Truck Forum' started by I.Reeves, Jun 15, 2008.

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  1. I.Reeves

    I.Reeves Full Member

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    Hey all,
    I have a 98 chevy c-1500 with a vortec 5.7l. It came factory with dual cats. I am needing to know if their is a way to by-pass the O2 sensors behind the cats so that i wont have a engine light come on.
     
  2. z07

    z07 Senior Member

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    Google "O2 Sensor emulators/simulators"
     
  3. MORROWMUDDER

    MORROWMUDDER Senior Member

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    not to sure if thats a real good idea, the O2 sensor helps regulate and adjust the air fuel mixutre making yer truck run right. if it has no data then it can either use to much fuel or to little fuel. mine does the same thing but what i do is unplug my battery to let the computers reset themselves. the light goes out for a week or two. but if you do that and you have a pass code for the factory stereo make sure you know the number if the security system is active.
     
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  4. Faster4344

    Faster4344 Senior Member

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    I believe Morrowmudder is correct in that the o2 sensors help regulate the air fuel mixture and they are needed but I its the front ones that do that. The ones that are in front of the cat the back ones behind the cat are for emmissions only to see if your cat is working properly I would go w/ the o2 simulator/eliminators. I might be wrong but im 99% confident with my answer.
     
  5. junior3382

    junior3382 Senior Member

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    You know, as the guy who constantly seems like the reduntant one here and simply agreeing with previous posts.... I have to agree with morrowrudder here, and also want to add, O2 sensors are not that expensive in the short term if you consider the possible long term negative effects, and the ensuing costs therin.... I would say you are better off replacing them, and doing it right the first time... Save the future headaches, or problems.... like having to replace the cats due to running to rich... Beleive me, that sucks. I chose to take the easy way and ignore mine on mt Mazda, and then, when I needed to, I realized heinsight is always 20/20, and now knowing that the cats alone for mine were over 1500 bucks... that 80 dollar sensor does not seem unreasonable. Granted, yours may be cheaper... but the principal applies. I would urge not to bypass, but to replace and repair....
     
  6. I.Reeves

    I.Reeves Full Member

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    Cool deal every one. I only want to bypass the rear o2's because i am thinking of gutting them out. i dont have 600 bucks to replace the cat system. so i wanted to go old school and just gut them like i did on my old 72 chevy step side. i know the cats help with emissions but with an engine that has 231,000 miles on it why not help it breathe easier.
     
  7. wojeepster

    wojeepster Senior Member

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    find signal wire on second o2 sensor (it is the one with .1-.9v on it with car running) cut wire insert 1 megohm linear pot in line set pot halfway.(500k) Put 1uf capacitor from signal wire (either side of pot to ground) leave o2 sensor in place. A working cat lowers signal voltage and smooths it out, putting a resistor in line lowers the signal voltage and the capacitor smooths out the signal. you can adjust pot if you need a little more or less.

    Do not do anything to the first o2 sensor, it controls the fuel injection.
     
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  8. I.Reeves

    I.Reeves Full Member

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    cool deal. i found a o2 simulator online for 30 bucks but i do need two of them. ill try em out when they come and if they work then great, if not well i tried
     
  9. keithr0005005

    keithr0005005 Senior Member

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    they wont work. simulators are for before the cats when you heavily modify a motor and you run an air fuel mixture that isnt the same as factory from what ive read. i believe the only way to eliminate the down stream sensors is to have computer re tuned
     
  10. 72'CaminoKid

    72'CaminoKid Senior Member

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    these era chevy engines are a PITA.... we've been fooling with the o2 sensors on my dads for about 3 years now and still cant get them completely right... let us know if you get everything right
     
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