Code p0420 after kooks lTH

Discussion in 'V8 5.0L Engine / Mods: Bolt-ons, Exhaust, Tuning' started by ked, Oct 17, 2019.

  1. ked

    ked Member

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    Hey guys , I'm sure this has been posted a couple of times , but I do have few questions.

    So I had kooks long tubes with green cats installed in my car by the Ford dealer and had the tune by bama from the American muscle tunes website since I bought an airfilter from them , I gave them list of parts and they gave me the tune.

    Anyway ..after about a week I got cel with code p0420

    Im sure you are familiar with this code

    I emailed the tuners and sure enough they told me it's the O2 sensors because of the high flow cats ..

    And that they can't legally do anything to disable the O2 sensors

    But one of them suggested going with spacer for the sensors.

    The questions here are


    Is there any danger on the engine or car from that code , or is it ok since it's just a reading error

    Will the spacers fix the issue and if so what kind ? I found that there is 90 degrees, 45 ... straight etc .

    Any other possible fixes ?


    Thank you so much
     
  2. Zelek

    Zelek Well-Known Member

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    They shouldn't turn off the O2 sensors, but they can turn off that code. There's a huge difference between those two statements.

    Spacers "might" work, but with the O2 sensors relocated, it's best to just have the tuner turn the code off. That code being on or off has no effect on your sensors going into a ready state which is a whole another gremlin to mess with.

    I seriously think the only way to ready the rear O2's once you have long tube headers is to go WOT within minutes of warming up the car and drive the hard really hard to heat up the O2's really fast so it thinks they're functioning up further where they originally were versus moved back how they are with long tubes. Otherwise, the stock tune is the only option and that usually makes them go green regardless of where the O2's are placed so it's a crapshoot. More on the tune than anything I think. There's some programming missing that the stock tune has.
     
  3. OP
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    ked

    ked Member

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    I'm copying their answer on my email ...

    --------
    We are not able to turn off any O2 sensor, EGR, or any emissions related codes. It is federally mandated that these systems are not to be altered or tampered with, therefore we can not support any disabling or work around of these systems having been removed or otherwise mechanically altered. Rear O2 sensors are read only sensors and will not effect your vehicles performance in any way.
    ----------
     
  4. Zelek

    Zelek Well-Known Member

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    I would get some spacers then. The Big Daddy's angled ones are pretty good.
     
    Performance nut and ked like this.
  5. Andy13186

    Andy13186 Well-Known Member

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    p0420 means you need to smoke a blunt to restore functionality

    on a serious note maybe you could tell them you are in qatar?
     
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  6. thelostotter

    thelostotter Well-Known Member

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    Vibrant J spacers worked for me with catted ARH long tubes.
     
  7. ugstang17

    ugstang17 Well-Known Member

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    In answer to the question, rear O2 sensors only monitor the functionality of the catalytic converter. It will not effect functionality or performance. However you will not be able to pass any emissions in that condition. There is another option here. IT has been beat to death in discussion if you search for it. They make a device (forget what its called now) that relocates how far into the exhaust stream the rear O2 sensor sits. This relocation allows the sensor to see less exhaust and therefore makes the ECU think everything is fine. Sorry but I do not bother with headers any these days so remembering what the item is called is not at the top of my list. If you do a search on this issue you will find the topic more than once.
     
  8. OP
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    ked

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    Thank you guys for the feedback

    Speaking about the spacers

    Found a couple for that vibrant brand ...a standard and a J style one

    Part numbers
    VIB-11621
    And
    VIB-11619

    Would any work ?

    It's a good thing that it won't affect the engine, I'm relieved to hear that .

    But that CEL is just bothering me , and ofc you can't remote start the car with the light on .


    As for emission tests, they are kinda easy when it comes to that test , I mean the car need to be in really bad condition to fail that .

    So currently I just want to get that light off cos it's driving me crazy ...and I don't want to keep clearing codes every few days .
     
  9. ugstang17

    ugstang17 Well-Known Member

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    Do search on the topic and you will find what people are using.
     
  10. FruityJudy

    FruityJudy Well-Known Member

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    Isnt your car just for offroad racing and you dont even tag it for the street? I dont know why they have a problem turning it off if thats the case
     
  11. ManBearPig

    ManBearPig Well-Known Member

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    Not really. Turning off the rear 02’s is how tuners eliminate the cat inefficiency codes. Some of the mainstream tuners do this, others won’t. My rear 02s are disabled in the tune and they aren’t even on the car since my TSP longtubes don’t have provisions for them anyway. Only issue with doing this is the pcm will show “not ready” status on the cat efficiency monitors and some states/counties will consider that an automatic emissions failure.
     
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  12. Performance nut

    Performance nut Well-Known Member

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    This will do the trick... I can speak from experience with this exact setup with the same exact problem.
     
  13. Zelek

    Zelek Well-Known Member

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    Pretty sure Lund turned off that specific code and left my O2 sensors on when I was "trying" to ready the O2's. On one of the tunes, I threw my very first P0420 and he gave me a revision with that code off. Every other tune, I could never throw that code. Some of the tunes I had previously with other setups actually had the O2's turned off. They don't do that anymore.
     
  14. Bluelightning

    Bluelightning Bluelightning

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    http://www.bigdaddiesgarage.com/angled-cel-fix.html
     
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  15. jmeiers

    jmeiers Well-Known Member

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