[mopargunguy426]

i have a 2001 ram 2500 with a v10. i was just wondering how to trick the downstream O2 sensor so i can cut out the cats without having any trouble when i have to get the truck emissions tested.
any ideas? thanks

 

[Bob Lincoln]

It's a violation of federal law to remove or disable the catalytic converters, punishable by a $2,500 fine for individuals and $25,000 for shops.  Not a good idea.  And not a good idea to cut out the catcons.  It won't help performance, it can cut power slightly by reducing backpressure, and it will pollute considerably more.  In some states, if you sell a vehicle that won't pass emissions or safety inspection, within the first 30 days the seller must pay to fix the vehicle to get it to pass.  There's really no upside to this.

 

[valiant67]

Even if there are no codes from the missing cats by tricking the computer, they will visually look for the presence of the cats during the emission test in many places.

 

[dak4x4]

And with no O2 sensors it will run in open loop, and your miles per gallon will be even worse than it is now. Assuming your after more hp, I'd explore putting a larger diameter exhaust system on it.

 

[ImperialCrown]

Leave the cats there. You will gain nothing by taking them out and it is a Federal law violation to do so. The PCM software looks for a cause/effect in the response from the O2 sensors when testing them. You just can't trick it by inserting a basic 0.2-0.8 volt sine waveform.
The computer commands the injector pulsewidth rich or lean and then looks at upstream O2 sensor response. The following downstream response tells the PCM that the cats are intact and working properly.
Your EFI feedback system is built around a working system of sensors and components and it is impossible and detrimental to try and defeat any part of it.