Catalytic Converter Question
- Thread starter Funcrazy1
- Start date
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98OzarksRunner
New member
It's against federal law to remove the cat. Unless you have a bad one and don't want to replace it, there's no advantage to doing so anyway. Your truck will smell like a dirty dump truck without it. If you were building a race car and wanted every last HP, removing the cat might gain you a few HP (on a 500+ HP car) but you won't notice any performance or mileage gains by removing it on a 183 HP 4Runner.
Wasn't going for performance gains on the 4runner. I forgot to mention my check engine light comes on for my cat. What can I do to get rid of this check engine light. I delete it and then it comes back on the following day.
if it's the P0420 code, either replace the cat(s) or get the URD O2 sim. you need a functioning rear O2 sensor for the URD to work though.
This will sound dumb but how do I know if the Rear 02 is good? I only have one cat on the 4runner. Sorry totally new to this stuff
Robb235
Senior Member
You can build your own O2 simulator, as described in the link below:
Rear O2 sensor bypass/CEL fix. - Tacoma World Forums
Unfortunately, this didn't work for me because I have the 2 cat "California emissions" vehicle. Cali emissions have a wideband O2 sensor upstream, and a narrowband sensor downstream. Apparently the ECU somehow periodically calibrates the upstream wideband with the downstream narrowband somehow. And so the simulator doesn't allow this calibration to happen, and it threw a code (I was getting a P0420 code before, which is why I was trying to simulate the rear O2. Now I have a P0136 with the simulator installed).
However, because you have a 1-cat, federal emissions style vehicle with both narrowband sensors upstream and downstream, the writeup posted *should* work for you. I can send you mine if you want since I don't need it. Just Paypal me $10 to cover the cost of the parts and shipping it to you, and it's all yours.
Mine is a 01 4runner and I guess I have a calif. style system with 2 cats? It's all original.. As I said I keep getting 0420 code and mechanic says that his computer is showing bad cat. I never replaced rear 02 sensor.. but did front one last year and got me thru emission... but lights for Check engine and 4wd Vac and other one..I know when we did front 02 sensor all lights went out last year.. I really don't want to put on a front cat. but if I do has anyone any suggestion on which one to get. Don't need the best but want something that's going to last a few years..
Robb235
Senior Member
I'd just replace the rear O2 sensor first. Even if your converter is truly bad, your rear O2 is due to be replaced anyways. I haven't had to go through emissions, so I haven't tried very hard at getting the CEL to go out.
You can hook it up to a scanner or test it with a multi meter, but if the front and rear haven't been replaced in say the last 100k+ miles (or ever), it's good maintenance to replace both anyway. If you're just looking for the quickest easiest "fix" for the P0420 code (and turn the cel off), the URD is the way to go.
