I own a 99 LE and was wondering about the cat. I took it to my mechanic because the check engine light was on, and he said it was the catalytic converter. I'm wondering, could I just gut the cat for now and be good? I don't have the money to spend on a new one right now, and was wondering since I read somewhere that there is a resonator after that cat itself, and the noise increase shouldn't be THAT noticeable. Is this true? Has anyone tried this? I know it will be illegal, but it's just till I can get some $$$ together to get myself another.
Yes the oxygen sensor was tested. I took it to a Toyota Dealership and they said it was for sure the cat. I've taken it this place before and they always know the problem. They said that a common mistake when it's giving that reading would be the sensor, but he checked it out and said it was fine, and that the cat was where the problems were.
So would gutting it fix this problem temporarily? And back to my first question, since the resonator is after the cat, will it make much more noise? And also, wouldn't it give a small boost in HP due to the fact that there's no disruption of airflow down there?
You might be able to take the cat off and hold it up to the light to see if it is clogged. I find it hard to believe your car suddenly dropped mileage due to a clogged cat, but it is possible. As others have said, I would suspect a bad O2 sensor which would be located before the cat.
Gutting the cat will always return better fuel economy and give a slight increase in HP, even if it isn't clogged. If it isn't clogged, expect around a 5% increase. You will hear more of your engine exhaust after gutting it. Also, I'm not sure it is legal and you won't pass an emissions inspection until you replaced it.
I believe the fine for tampering with emission control devices is still $10,000. So I would be very supprised if any shop would do that for you. I suppose you could do it yourself but its a lot of work for something youll have to fix later anyway. I would suggest to just save up and have it fixed properly rather than trying to mess around with it.
The maximum penalty for tampering with an emission control device is $2,500.
No legit shop would knock the element out of a catalytic converter, but it isn't very much work. It can be done in less than 30min, and it would be very difficult for the EPA to actually find out that the device was tampered with. I had a gf drive for years with the element knocked out of her cat, and she enjoyed better mileage, power, and sound from the engine.
True, its unlikely you would be caught. Wether its eays to do or not for the do it yourselfer really depends on how easily it comes off depending on milage/age and if your living in the "rust belt" area.
I'm assuming you got a P0420 error code being thrown out (fairly common on 8th gen Corollas)?
Gutting the catalytic converter will guarantee that code P0420 to be thrown - will make the come one all the time. Only thing that code implies is that the downstream O2 sensor (post-cat) is reading a signal that is too similar to what the upstream O2 sensor is outputting (pre-cat) - does not automatically mean the catalytic converter is bad.
A drop in MPG of that order is pretty indicative of a "lazy" upstream O2 sensor. A sensor that is still "sort" of working, but has not degraded to the point of throwing a CEL for a faulty O2 sensor. Poor chassis ground can also cause all sorts of headaches for these emission's related codes - confuses the ECM.
Once "quick-fix" might be to use a sparkplug defouler - basically an extension "tube" that moves the downstream O2 sensor further away from the exhaust stream to yield a different reading - could be enough to trick the ECM in reading a PASS condition for catalytic converter efficiency and is pretty cheap to implement ($5 for the part, need to drill outend of the defouler to allow enough exhaust gases to pass through or you'll end up with CEL).
These catalytic converters are designed a little differently than the ones of the past - one, they contain less precious metals than before and have enhanced enhanced flow (dyno test have proved that you gain about one HP going from a stock cat to a straight pipe). With the OEM sized piping, the resonator has the greater influence to noise compared to the catalytic converter. Not uncommon to see owners running aftermarket exhaust systems (header, metal core cat, near straight through muffler, larger diameter piping) run two resonators inline to help cut down the noise levels and attentuate the sound a bit.
It doesnt make sense to gut your cat because you o2 sensor will still read rich right after the cat because its not doing anything. If you bang on the cat and it rattles then it's clogged and you need a new one. When you buy a new one don't go for a cheap 60$ no name brand because it will have no precious metals and not last very long at all. Just buy a new cat and have your dealer install it. Its not a huge deal
It doesnt make sense to gut your cat because you o2 sensor will still read rich right after the cat because its not doing anything. If you bang on the cat and it rattles then it's clogged and you need a new one.
It makes sense when the gf can't afford a new one, and would like to enjoy the benefit of 5% better fuel mileage. Her cat wasn't clogged; the element inside had broken free and rattled within the housing.
It makes sense when the gf can't afford a new one, and would like to enjoy the benefit of 5% better fuel mileage. Her cat wasn't clogged; the element inside had broken free and rattled within the housing.
lol well then i guess it makes sense, i didnt no it was rattling around in there. Then yeah it sounds like you made a good choice.
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