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Well, thanks for the rude answer. I did a search in this forum, but had more questions. Every time I post in a past thread about something in a forum, I get admonished and told to start a new thread. Everytime I start a new thread, someone says "do a search idiot". I participate in forums regularly, and while helping many people on a variety of questions, I too sometimes get tired of the repetition. However, before I get snarky with someone, I just tell myself it's time for a forum break...
Remove/replace the cat = muffler shop. They have to be cut off and welded in.
your best bet to fix the issue is to find someone with HP Tuners, and ask them how much they will charge you to tune the code out (assuming you are not in an emission controlled county). You are looking at $100 to have your car licensed to their HP Tuners software, and then whatever that person is going to charge you for their time.
Remove/replace the cat = muffler shop. They have to be cut off and welded in.
your best bet to fix the issue is to find someone with HP Tuners, and ask them how much they will charge you to tune the code out (assuming you are not in an emission controlled county). You are looking at $100 to have your car licensed to their HP Tuners software, and then whatever that person is going to charge you for their time.
I assume, of course, that you are suggesting this for his race-only vehicle that will never be driven on a public road. Otherwise it would sound like a conspiracy to violate federal law, much like what all those diesel shops recently got massive fines for. Then again, maybe it is just coincidence when new posters start by asking questions that any google search would have answered.
I assume, of course, that you are suggesting this for his race-only vehicle that will never be driven on a public road. Otherwise it would sound like a conspiracy to violate federal law, much like what all those diesel shops recently got massive fines for. Then again, maybe it is just coincidence when new posters start by asking questions that any google search would have answered.
That is why I said "assuming you are not in an emission controlled county"
I assume, of course, that you are suggesting this for his race-only vehicle that will never be driven on a public road. Otherwise it would sound like a conspiracy to violate federal law, much like what all those diesel shops recently got massive fines for. Then again, maybe it is just coincidence when new posters start by asking questions that any google search would have answered.
There's people who has been here for years asking them Google questions too.
So, if I may be so naive and much less informed than you guys...
I did mechanic, machine work, fabrication, engine building for 40 years, then got out of it in late 90's. I am not up on OBD2.
How tough is it to buy HP Tuners and tune it myself? I did understand that correctly that it can be tuned to run correctly and not have a check engine light after removing the cat, right?
Can I ask without getting shot where I can learn more about all this, including 02 emulators??
Simulators, and two of us said google. You literally just asked where you could learn about them so can't get any more asking of that as a response. Simple search will explain how they are a resistor.
If you have a laptop and want to spend $400+ on the computer program for that then go ahead. That's just the basic program too.
I think the simulators are the cheaper alternative here.
Simulators, and two of us said google. You literally just asked where you could learn about them so can't get any more asking of that as a response. Simple search will explain how they are a resistor.If you have a laptop and want to spend $400+ on the computer program for that then go ahead. That's just the basic program too. I think the simulators are the cheaper alternative here.
You wouldn't get much of a return on investment for a tuning suite on a V6. I don't know if they're even supported.
More to the point, I don't see any reason for removing the converter on that car unless it is clogged or malfunctioning and causing driveability issues. If it's working properly, you're not going to gain much of anything by doing that.
Yeah, we are getting an intermittent check engine light, and converter codes. It has always been SOP in my performance oriented family to lose the cat on anything we are going to drive for more than 10 minutes. Never once failed to see an increase in fuel mileage, sometimes quite a bit. Usually a slight power boost too.
I have thought of blaspheming and putting a converter on it, but she would prefer not having one as long as we can turn the light out.
I have seen various fixes talked about, from installing the second O2 sensor spaced out on an anti-fouler, to a resistor (that is never explained), to 100+dollar electronic devices that are no longer sold...
The second O2 sensor tells the computer that the cat is there, and working properly. So far, so good, and maybe easy. However, from time to time the computer does a quick self test of the converter. That's where it gets complicated. If the computer does not receive the proper info, it turns the dam light on and throws a code. That's why some "fixes" work... until they don't. The "fixers" don't come back on to post and tell you about that.
Vettepilot
Last edited by Vettepilot; Dec 5, 2024 at 10:53 PM.
How do you remove catalytic converter and not get check engine light/trouble code?
What's the work around? Surely people have done it...
Thanks a bunch!
They sell 18mm Dorman non-foulers or in ancient terms oil burners
at O’Reilly auto parts and they come in two to a package. Buy two packages and drill one package out so that your O2 sensors will screw down into them. Then screw the the first one into the second one that’s not been drilled out and install. This method pulls the O2 sensor away from the exhaust and tricks the ecu into thinking cats are still installed by cutting half the exhaust flow down.And brother I already know how it is to ask questions and we’re not all geniuses out here but most of us forgot more than the smarta___s will ever know. And yeah we can google about anything but doesn’t guarantee the correct answer. Feel free to reach out to me if you have any problems. Sorry d___ I’m not in a state where emissions is tested but this is for off-road and entertainment purposes only!
Last edited by KDJnz1973; Dec 5, 2024 at 10:56 PM.
Yeah, we are getting an intermittent check engine light, and converter codes. It has always been SOP in my performance oriented family to lose the cat on anything we are going to drive for more than 10 minutes. Never once failed to see an increase in fuel mileage, sometimes quite a bit. Usually a slight power boost too.
I'm definitely on board with this line of thinking. The only cats that I have any use for are the ones that catch and kill rodents around grain silos, etc. Other types of cats should be gutted or eliminated whenever possible.
Originally Posted by Vettepilot
I have seen various fixes talked about, from installing the second O2 sensor spaced out on an anti-fouler, to a resistor (that is never explained), to 100+dollar electronic devices that are no longer sold...
O2 simulators are still sold. Pricey, yes, but they work. Here's a link (unfortunately they are sold in pairs, but you would only need one for a single cat car so the other could be sold or kept as a spare):
In the past, some folks have made their own O2 sims using resistors, but I've never done this so I can't help with that option. But it's cheaper than buying the prefabbed ones.
You wouldn't get much of a return on investment for a tuning suite on a V6. I don't know if they're even supported.
More to the point, I don't see any reason for removing the converter on that car unless it is clogged or malfunctioning and causing driveability issues. If it's working properly, you're not going to gain much of anything by doing that.
But yes, not financially wise to put that much money into this situation for just a light, why Simulators would be the better investment.
Resistor method is just the proper resistor across the two wires that aren't the 12v and the ground, so atleast the wires are easy to find the resistor value would take some research.
Here's my thoughts on the resistor thing, and postulation about why certain "fixes" work, until they don't.
Point. The function of the second, downstream O2 sensor is to verify that the cat is in place andfunctioning.
Whatever the computer expects to see to solely verify that the cat is there, can be emulated, possibly by a simple resistor.
However, my understanding is that to verify operation of the cat, the computer periodically alters the fuel flow momentarily, and it expects to see a certain change in the feedback from that second O2 sensor. This feedback cannot be accomplished with a simple resistor, and would result in a thrown code and a check engine light.
In other words, any "fix" would have to be something that knows when "self test" has been initiated, and sends backthe expected value, probably by momentarily switching to a second resistor.
This is my "read" of the whole situation. Can someone verify if I've got it correct??
Here's my thoughts on the resistor thing, and postulation about why certain "fixes" work, until they don't.
Point. The function of the second, downstream O2 sensor is to verify that the cat is in place andfunctioning.
Whatever the computer expects to see to solely verify that the cat is there, can be emulated, possibly by a simple resistor.
However, my understanding is that to verify operation of the cat, the computer periodically alters the fuel flow momentarily, and it expects to see a certain change in the feedback from that second O2 sensor. This feedback cannot be accomplished with a simple resistor, and would result in a thrown code and a check engine light.
In other words, any "fix" would have to be something that knows when "self test" has been initiated, and sends backthe expected value, probably by momentarily switching to a second resistor.
This is my "read" of the whole situation. Can someone verify if I've got it correct??
Thanks for the answers thus far,
Vettepilot
In theory, you are pretty much correct. However, I think you may be missing something. The catalytic converter alters the composition of the gases in between the front and rear sensors. Therefore the rear sensor should always show a different value from the front, within a range the computer is programmed to be acceptable. If something were wired in to the rear sensor to alter the reported voltage from the front by approximately the same amount that the change in gases from the catalytic converter alters the voltage signal, then why would it matter whether it was specifically happening during a test cycle or not? In theory, of course.
Here's my thoughts on the resistor thing, and postulation about why certain "fixes" work, until they don't.
Regarding my experience with LS1 F-bodies, O2 simulators work - permanently (unless something happens to damage the simulator). I've used them on multiple LS1 F-bodies, in one case for many, many years.
Regarding your question of operation, the simulator does not show a constant value (at least this is what I have seen on my scanner). As mentioned above, it continually fluctuates within a certain range to accommodate for such "tests" run by the PCM. I would assume that later model cars have more advanced PCMs that can perhaps detect this, but not the LS1 F-bodies (and I would assume that the V6 cars would be the same). Even my '02 Z28, with the most advanced PCM that was used on any 4th gen F-body, still did just fine with simulators (all DTC tests would run and pass).
As far as the DIY resistor method or other "fixes" (beyond custom tuning), I have no idea. Again, I've never done that.
Catalytic Converter 
