430 - One of my precat o2 sensors is in closed loop | FerrariChat

430 One of my precat o2 sensors is in closed loop

Discussion in '360/430' started by carguy007, May 15, 2021.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #1 carguy007, May 15, 2021
    This is an Odd one. One of my pre-cat 02 is in closed loop. But the other pre-cat O2 sensor is an open, and reading live data. Even more strange I don’t have a cel. I found a thread where someone had something similar going on but it was a while back and there was no resolution. Anyone have any ideas? Needless to say I ordered a new O2 sensor. For reference car has headers and no pre-catalytic converter’s And runs well.
    Image Unavailable, Please Login Image Unavailable, Please Login
     
  2. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #2 carguy007, May 15, 2021
     
  3. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    #3 mike32, May 16, 2021
    Use a meter to compare the resistance reading between the sensors. Sounds like one has a broken wire, so you should be able to find it
     
  4. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #4 carguy007, May 16, 2021
    Yeah something is amiss. Once the car is warmed up all the sensors should be in closed loop and relying on actual feedback from the sensors not the default settings in open loop.
     
  5. flash32

    flash32 F1 Veteran

    Aug 22, 2008
    5,679
    Central NJ
    Full Name:
    Dominick
    #5 flash32, May 16, 2021
    Could be the ECU thinking it is still cold caused by temp sensors, could be o2 sensors, could be tool as well .. so you have a cheap elm dongle with a simple torque or EOBd facile



    Sent from my moto g power using Tapatalk
     
  6. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #6 carguy007, May 16, 2021
    These readings were taken with my Launch X431. Temp seems fine when checking values with the tool. I will poke around some more. What is odd however if I select EGT it shows a value of -25. I am not sure if the tool should be picking up a value for EGT however.

    Anyone with launch get a temperature reading when they select EGT?
     
  7. flash32

    flash32 F1 Veteran

    Aug 22, 2008
    5,679
    Central NJ
    Full Name:
    Dominick
    #7 flash32, May 16, 2021
    On the header.. there should be a thermocouple .. not sure if that is playing into this

    Number 19 on parts diagram

    Sent from my moto g power using Tapatalk
     
  8. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #8 carguy007, May 16, 2021
    Yeah it’s there- but I think both my thermos are damaged. I am not sure if they interface with o2s. It’s I tereting one side is reading.
     
  9. flash32

    flash32 F1 Veteran

    Aug 22, 2008
    5,679
    Central NJ
    Full Name:
    Dominick
    #9 flash32, May 16, 2021
    I am thinking the thermocouple tell the ECU to go closed and then it starts to use o2 sensors



    Sent from my moto g power using Tapatalk
     
  10. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #10 carguy007, May 16, 2021
    I think you are right. I switched o2 side to side. No change. I then thought I would do the same with thermos. When I removed them both discovered one of them was jingling around inside and the element was broken inside. My theory is that when one thermo is bad it will go in open loop but will actually throw cat protection codes for both banks because it triggers a slowdown light. It was too late to restart the car to confirm as I moved the thermo to the other side to see if that side would go to closed loop. Pics of the good one vs the broken below. What a pain in the ass.
    Image Unavailable, Please Login Image Unavailable, Please Login
     
    EastMemphis and Qavion like this.
  11. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    #11 mike32, May 17, 2021
    A bit more than a broken wire is that.
     
  12. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    843
    #12 carguy007, May 17, 2021
    Crazy right - I was super careful with them too, so this happened just from the sonic blasts from my exhaust gas..lol.
    It's a stupid system and apparent why Ferrari ditched it as they progressed with the f430 and Scud.
     

Share This Page