Hi
What does the catalyst converter effect on the engine if it defected (shows failure in computer diagnosis )
Is there any problem if I leave it and not replace it ?

And in case of replacing it should I replace the Oxygen sensor Along with it ?

Regards

 

The catalytic converter is an emissions component that reduces the exhaust gases that comes out of our vehicles. Here in the States, most states have emission inspections and require emission devices to be present and not to be tampered with. Overseas, I see that your from Dubai, it may not require such inspection.

If the catalyst is defective or missing, the O2 sensor detects more air in the exhaust stream and the ECU will command more fuel(longer fuel injector pulse width) causing a slightly more rich condition than the computer wants.

I heard people remove the catalytic converter for boosted engines, high performance applications but they also run standalone EMS units different computers to control air/fuel ratio. On a stock vehicle, there is really no point in removing it, all this causes is poor gas mileage, check engine light.

If you replace the CAT, it is not require to replace new O2 sensors unless there is a fault code for them. I personally would get an aftermarket CAT if I needed one, they don't run near as much as a factory OEM CAT that can cost you over $1k easily.

 

I dont know how many people ask this question, sooooo many that I am glad I am able to save so many people thousands of dollars who would have replaced their CAT for nothing. Start with replacing your O2 sensors, 95% of the time thats the issue. When the O2 sensors aren't functioning properly the CAT produces incorrect readings and the computer throws a CODE that says CAT converter not running at optimum efficiency blah blah. All that means is SOMETHING is not allowing the CAT to function properly, doesnt mean the CAT itself is bad. These cats are very expensive and almost can last the life of the vehicle. Change the O2 sensors and report back, I can almost guarantee thats the problem.

 

and whatever you do, DONT buy an aftermarket CAT, they are the biggest pieces of crap in the world, learn from MY mistakes, they wont even last you a year, ESPECIALLY in the V8 GS. The precious metals inside the CAT that are supposed to be there are basically non existent or replaced with cheaper crap that may be good for a piece of s h i t ford but not a Lexus.

 

Hmm. I had cat eff code(gs300). Replaced the entire manifold/cat assembly with a magnaflow...problem solved and that was over a year ago.

I do agree that the only right choice for 02 sensors are OEM. Aftermarket sensors are truly junk.

 

This is only because either your problem was an exhaust leak or the O2 sensor in which case when you changed the whole assembly it comes with the O2 sensor. so you changed it for nothing sounds like. You changed the entire exhaust manifold? May I ask how much did that cost ?

 

Thanks a lot my friend for this information
That's correct most of people here in Dubai they remove the catalyst convertor when get fault in computer diagnosis
So you recommended me to replace it with use one (if it is in good condition ) rather than buy and new one

 

So you recommended to replace brand new O2 sensor and not used one

 

Thanks brother for your information
Intact here in Dubai most of the used spare parts are comming from Japan ( junk japanese car )
Most of these cars are in very good condition , physically look like new. But nobody knows how much it will run before get fault again

 

Thanks a lot brother

 

Yes. I think I had leak in exhoust system I here a sound but. The mechanic said its from the manifold
So first let me fix the leak and then look after the other parts

 

No, the header assembly does not come with 02 sensors, I reused my old ones. The cats had 240,000 miles on them and the asshat that owned the car before me did not run premium. And no leaks either. Catalyst eff codes are generally due to worn out cats not 02 sensors. $550 for the magnaflow header assembly from summit racing...

 

If you have any Catalyst Inefficiency codes - p0420 or p0430 and do not want to replace the catalytic converter(s) or 02 sensors, you can use a O2 simulator since your region does not require emission inspection. This will eliminate any Catalytic converter codes that the ECU is throwing,

I am running one in my project car that has over 260K miles with bad cats and the light hasn't came ON since I installed it 2 months ago.

http://www.bigdaddiesgarage.com/straight-cel-fix.html

 

Yes, fix the leak first as that should make the check engine light go away. Then there will be no need to worry about replacing anything else!

 

Yup, those codes are quite frequently caused by a leak in the cat gaskets, replace the gasket(s) that are leaking and there's a very good chance your code will go away.