Fooling Rear O2 Sensors?

Discussion in '96+ Vortec Performance + Computer Swaps' started by 98chevy2500SS, Dec 7, 2019.

  1. 94_Z71

    94_Z71 Newbie

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    As others have already pointed out, Black Bear can tune your computer to delete the rear O2 sensors. I know this for a fact because I've had it done. My truck only has the front O2 sensors and no loss in driveability.
     
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  2. kennythewelder

    kennythewelder B31-3 (6-G) certified

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    If you go back to page 1 and click the link to my write up on this, everything you need to know on how to make a set of 02 simulators is in that link. The set I made for my 97 5.7L have been on my truck for several years. Never a CEL with the simulators installed. I did get a CEL with just spark plug spacers.
     
  3. b454rat

    b454rat I'm Awesome

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    my Yukon isn't on the road yet, (thanks NYS) but drive it around lil bit. Light still hasn't come on yet.
     
  4. 98chevy2500SS

    98chevy2500SS Specializes in Accessories 101

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    Kinda forgot about this thread, but thought I'd give an update on the spark plug non-fowlers. No codes for the cats in almost 2-2.5 months now, so I'd say it's a success. Don't know if it's any different for other trucks, but for how cheap they are, they are definitely worth a try.

    For my 97, all I had to do to make the O2 sensor to fit into the non-fowler was to drill a 1/2" hole on only two of the four non-fowlers.

    I didn't have to do this on my 98, since I was able to have one of my college instructors delete the cats through HPTuners.

    I will have to remember to update this come winter to see if they still work. My 98 used to give me codes every once and while when I had the cats still on it, but only in the winter, never in the summer, so I will be surprised if these non-fowlers keep the codes off in the winter.
     
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  5. Busted Knuckle

    Busted Knuckle OBS Enthusiast

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    Non-foulers are completely useless. You have to provide a switching signal to the ECM to look like there is correct activity. Probably a 50% duty cycle square wave between 0 and 1 volt would work fine. This can be made for a few dollars with an EE buddy and an NE555 timer circuit. OBD2 is a pain. Why us TBI guys got the better deal.
     
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  6. Supercharged111

    Supercharged111 I'm Awesome

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    Yeah it's real hard for me to disable rear O2s with my tuning software and enjoy all my extra power.
     
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  7. kennythewelder

    kennythewelder B31-3 (6-G) certified

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    The cat simulators I made several years ago work grate. Yes, you can build some simulators as you mentioned, but some of us are not electronic tech and lack the skill to do a project like your talking about. The 02 simulators I made are an easy fix, and work very well because the ECM still sees what it os looking for, from the rear 02 sensors. The write up on what, and how I made my simulators is on the first page of this thread. Its about the 4th post down from the top, I think. Like I said, been on my truck over 5 years, and has worked grate from day one, and is still working.
     
  8. Supercharged111

    Supercharged111 I'm Awesome

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    And the rest of your OBDII has been good to you, hasn't it?
     
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  9. kennythewelder

    kennythewelder B31-3 (6-G) certified

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    Yes, no problems at all.
     
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  10. b454rat

    b454rat I'm Awesome

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    I been driving my Yukon around, and, CEL still hasn't come on. I'd think by now it would have. But I picked up a 98 4 door 2wd, and tho the light is on, it's not for the O2 sensor, and it is missing 1 cat. Other is there (dunno why lol) but plan on getting rid of it. The light is on for P1345 code, guy said he did new intake gaskets, and prolly didn't put in the exact spot.
     

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