Catalytic converter help

Ok guys I have a 98 ext cab 4x4 4cyl tacoma . My
Cc is bad . Should I cutt off or replace . I don't have to go for them emission test ( I think that's what there called ) but I thought about cutting off would it perform better or what tell me what comes with cutting it off ?? I know a new one is exspensive so you guys who have done it tell me what to do .i have lost power and I am thinking that's why . I have had it scanned by auto zone . That's what they told me it's bad .
Thanks so much gentlemen

 

Oh if I cutt it I plan on putt a pipe back where the cat was . So it isn't as loud once again thanks

 

You can get them for a pretty good deal at Summit Racing. I had to replace mine since I had to go through emissions in Arizona.

 

Are there O2 sensors before and after the Cat? If so, then there would be some more work involved than just cuttting it out.

 

Yes they are I can't cutt them out it's a direct fit bolt pattern so it's wouldn't be that bad

 

I would not suggest removing the Cat. The computer needs to read both O2 sensors reading the correct numbers. Why did you go to AZ and have them use their simple tool on a complex machine? All they want to do with that is sell you parts so you can be a parts changer, not a mechanic.

Take it to the local dealership or shop and have them look at it. Even if you have to pay a diag fee, you will still save a lot of time and especially money in the long run.

If the AZ guy is telling you that your O2 sensor is bad, which one is it? If it is the one before the CAT, then the sensor can just be bad. If it is the one after the CAT, then you are more than likely losing oil down the exhaust, which is fouling up the CAT, not burning off and throwing off the second sensor.

When was the last time you checked your oil? Does black smoke come out of the tail pipe? Does any smoke come out of the tail pipe? CAT's should work for a heck of a long time if they are only cleaning gasoline fumes, not burnt oil. If you have a bad ring or valve, then you have found your problems.

Again, the sensors are there to tell you that something up stream is not working properly. Go to someone that has the proper diag tools/scan tool to get your information.

 

My cat on my 96 was rattling so we cut it off welded in a pipe and put a rear o2 simulator on from URD. Everything works fine no check engine lights.

For me it was either pay $100 for an aftermarket cat that may go bad again. Or weld in a pipe for free and get the o2 sensor simulator for $100 that should last as long as the rear o2 is still working.

 

I have the simulator too. But didn't remove my cat yet. But, my truck has two cats. One in the front that is angled down, then another right after that. The second one is straight with pipe on both ends connecting it to the first cat and to the rear portion that has the muffler. I'll find a diagram.. But I'm wondering if this simulator is supposed to be a temp fix. From what I understand of o2 sensors, they adjust your mixture and help your truck run better depending on the mixture. So if the simulator is sending a constant 'perfect' signal, then it means your truck isn't running as it should when it's lean or rich right? Or am I wrong? Maybe it's only the front o2 sensor that reads and adjusts mixture. And the rear just reads if your cat is performing as it should?
I want to remove my cat too because I don't even require emissions and want to get something set up but in such a way that it will still adjust properly using the o2 sensors. What I was thinking, is getting a single cat replacement, New sensors (IF they are bad, I'll have them tested first) and have a shop throw it all together. I was quoted about $400 to get the whole setup installed. Not including the cost of the cat,muffler, and sensors. So for a preffesionally installed system with pipes being routed from the manifolds back and o2 bungs welded on i think it's a pretty good deal. But I need help understanding how big a role the o2 sensors play versus leaving the simulator in place, because that'll save me money if I don't need to worry about getting new sensors. And also why there's two cats and if it's gonna perform the same with only one. And whether or not to get a high flow cat to match my cai. I'm sure whatever info you can provide will also help the OP too. I'm thinking the same thing that my system isn't performing as it should and losing performance. Either by the cat itself or the combination of that and the sensors not reading correctly.

 

Your front o2 sensors adjust a/f ratio your rears just see if the cat is working properly. The rear o2 simulators just tell the truck that the cat is working properly. This prevents a CEL and from time to time the ecu will use the rear o2 sensors to recalibrate the front sensors. Go to urdusa.com and then to the rear sensor simulators there is information on this.

Having bad cats can cause some performance issues. The honeycomb structure will break apart and causes blockage/back pressure in the exhaust. When I cut my bad one off and put in a pipe and the simulator and the truck ran a lot better.

If there bad you can just cut them off put in pipes and the simulators and you should be good.

 

Ah I see. Been a while since I looked up any of this stuff. So the front o2 is most certainly needed. Not sure if I need a new one. Will have to research that again to learn how to test it. Any thoughts on what to do since I have two cats? If I can just have the shop install straight pipes from the manifold back with no cats, with a muffler and weld in a single o2 bung for the front then I'll do that. Or just buy a cheaper weld on cat to have them install too??
Here's a diagram of my setup..


I think it would be a lot cheaper to have them run plain pipes. Angled down from the manifold with a single o2 bung, back to the muffler turned down before the axle. That way I don't have to purchase anything except the muffler. Might even use the stock muffler because I want it as silent as can be. Then all I'll be paying for is the installation about ~$400 would be my guess. As long as my front o2 sensor is still good.

 

If your gas milage hasn't suddenly decreased and you don't have a check engine light then the front sensor is fine.

But you still need to keep the sensors with the simulator on them. You cant just run the front one.Just cut both cats out and replace them with pipe.

 

Yeah mpg went down like 2. I did go from 32x11.5x15 tires to ones size bigger though to 33x12.5's. But I wouldn't have thought that'd cause that much of a decrease.
But thanks! Finally got an answer to this. Will definitely be replacing all with just pipe then since I don't need them. Now to figure out what muffler to use. And this is kinda a newb question, but would there be any concern using the stock muffler? Like, do they go bad and cause any performance issues at all? I wouldn't mind getting a new one but from what I hear there's not really anything quiet as stock. If I can get one for less than $50 thats close to stock as possible then I'll grab it... I'll be looking in other threads regarding this but if you know off hand I'd appreciate it.

 

The mpg difference is probably the tires. Just to make sure we are on the same page you will need all the o2 sensors front and rear you can't just put new pipe in with one o2 sensor.

And not sure about aftermarket mufflers that are as quiet as stock. And the stock muffler will go bad, the packing inside the muffler can fall apart and rust can start making hole in the muffler.

I had to replace mine because it was starting to bust open on a seam weld, but I replaced it with an aftermarket one. Thexausht is pretty load for a 2.7 and has a drone on the highway, but I got used to it.

 

Oh yeah that's right. Forgot that the simulator plugs in in between the cable. Guess it still needs to be able to read something there.
And I've been thinking about this more and I may have to get the shop to have it set up with a removable pipe just in case I move somewhere that does require emissions. That way I can just throw one on later when that time comes. I'll have to make up a diagram for them. Make it as painless as possible for me later down the road. He'll I may just get a cat anyways. But that'll be a few years of wasted use on it. Guess I'll go all out and get what I need now...

 

If you do end up wanting to just replace the Cat, I have a brand new AP Exhaust OEM replacement cat for your truck Part#645355. 50.00 shipped.

 

Just another friendly reminder: Catalytic converters are required at the FEDERAL level, not just the state. While your state may not have emission laws, the federal government says you must have your cat no matter what state you live in. Removing it is technically a federal offense. Not to mention that while YOU may not care about the long term effects, it is still bad for the environment. Take care of your truck properly, and try to do your part in our kids and grand kids to have at least SOME semblance of clean air to breath in their future. Please, be mindful of fixing your truck right. If you will spend hundreds of dollars on a lift kit, or tires, or stereo equipment, take the time and money to just replace the cat correctly.

 

Is it a federal offense to remove a defective cat? Having a defective one on is no different than not one on at all.

 

It is a federal offense to DELETE your catalytic converter. Perhaps I should have been more clear. You can REPLACE it if you want, but you cannot remove it and install a straight pipe. You have to reinstall a replacement catalytic converter.

 

I would try to gut the cat. That way you look legal.

 

Why not just actually fix the truck the right way? I just don't get it.