catalytic converter causing performance issues

Ok so I've replaced My catalytic converter because I had the p04200 code come up rest the light and it lights back up so what am I looking at here a bad o2 sensor or what all I'll is I'm losing performance it's like the truck is constantly bogged down after the light come on

 

http://www.obd-codes.com/p0420

 

Welll, it could be a bad sensor. If your sensor is bad you could be going into open loop when the CEL comes on, but even so it shouldn't cause MAJOR power loss. I'd just replace the sensor with an 02 simulator from LCE, that way, no matter what, the sensor is going to tell the computer that everything is A-OK. It's also nice if you want to do silly shit to the exhaust because you won't have to worry about throwing codes. Having said that, a simulator will remove the post cat 02 sensor as an effective early warning/diagnostic tool. Also, make sure you only have one cat; my taco was cali-spec and had two; you could have replaced the functioning cat and left the shitty one in. The heating circuits that warm up the 02 sensors often die in the 1st gen tacos (mine did), as well, but that usually throws a different code (not always). I would say if you don't plan on eliminating the cat or changing to a high flow cat then just replace the sensor. If you think you might straight pipe it someday, go with the simulator. I put on LCE long headers and converted my dual cat cali-spec Tacoma to a single high flow cat and I still didn't throw a code even with the factory 02 sensor.

 

So beyond the parts listings for cali-specs, I should not have to worry about buying a cali-spec CAT if I only have one cat? Mine is the 2RZ 2.4 regular cab 2WD. I was just wondering how picky computer will be with a 49-state cat versus a 50-state cali-spec catalytic converter.

Researching Maganflow - appears to be mid-grade according to price but I have not idea if it's mid-grade performance wise and getting rid of P0420 once and for all or at least until the the CAT fails again.

 

There are OBDII compliant cats available, if you want. About $300 alone. Magnaflow should have them. As well as Vibrant Performance.

 

Again, I recommend the 02 sim. from lceperformance. $110, you plug it in yourself; done; you'll never through a cat code again. Update: my taco finally did throw a code and I dropped this in, fixed it in one minute.

 

Believe me I looked at your advice closely and, if I was off-road 100% or in a pinch, I would certainly take your advice. I am not convinced that a sim is the correct solution for my vehicle or that it would pass emissions testing in my state when I need it to. In fact, there is a A/F feedback control loop that I am watching closely via graph output from my ODBII scan tool.

After reviewing the following article, http://www.obdii.com/articles/Understanding_Oxygen_Sensors.html, I want my my air/flow feedback control loop to work properly. BTW, I am not in a pinch and I am not driving off-road 100%. However I want to tune my my new/used vehicle to optimum performance; that is, if I can stay within my planned budget for this vehicle. I'll probably go ahead replace the A/F and O2 sensors based on routine maintenance advice from this article, http://www.obdii.com/articles/Understanding_Oxygen_Sensors.html, too.

 

I beg to disagree with your cost estimate for ODBII compliance. This is over double what I have found in Magnaflow. Did you mean the ODBII enhanced versions for California/CARB/50-state emissions? I would agree that those cat's generally range from $150 - $300 depending on source and manufacturer.

 

The second sensor does not contribute to your air/fuel ratio; it only monitors the performance of the catalytic converter. You will run normal loop with a simulator. A simulator will pass emissions as long as you don't live in cali, or (and this is only if your cat is COMPLETELY non-functional) if you live in a state that uses a "sniffer" test that measures actual output from your exhaust. Again, even in those states that have a sniffer test, you only need to pass a very generous emission standard that applies to all passenger, noncommercial vehicles. (A Honda Civic is held to the same emission standard as a Chevy 2500)Your specific vehicle computer is looking for a much narrower set of emission metrics, and thus, the light comes on well before a vehicle would fail a sniffer test. The simulator is plug-in dealer compatible and will not fail any computerized scan tool test required by your state.


*and actually, even though it isn't technically CARB legal, as long as your cat isn't gone and they don't look under your seat to see if you have a sim. inline, you'll pass in Cali. too. They'd have no way of knowing.

*and oh yeah, it's highly unlikely that you'll find a non OEM aftermarket cat for under $150 that won't throw a code. Aftermarket manufacturers just straight up lie when they say that their cheap cat won't throw a code.

 

http://www.partshopper.com/item/magnaflow-448005-universalcatalytic-converter/

http://www.partshopper.com/item/magnaflow-23886-direct-fitcatalytic-converter/

http://www.magnaflow.com/02catalytic_converters/02product/shopdisplayproducts.asp



All depends on which version you are looking for. I'm not sure yours is the 2.4, but it was just what I used for reference. The Fed standard is clearly the cheaper choice. Since you don't live in New York, I ruled that one out. I only keep the California one, since theirs are the most stringent. As long as the Fed standard one is metal, it should still prevent the CEL. I believe that only their high flow ones are the ceramic core, from Magnaflow.

 

Thanks for the listings for our comparisons - I remember seeing those before I went to the Magnaflow directory lookup. I used the Magnaflow directory to find this one for my 2RZ : Magnaflow 99204HM and received this week. Will probably schedule installation next week.

 

"the light comes on well before a vehicle would fail a sniffer test. The simulator is plug-in dealer compatible and will not fail any computerized scan tool test required by your state."

Good to know. I remain undecided about what to do now - I thought I was doing pretty good with my troubleshooting of 0420 emissions crap based on output from my ODBII device. Now I am thinking I should have ignored and gone for a simulator right away on the downstream O2. Do you think I should keep the OEM cat on with a new SIM or put the new Magnaflow 99204H on when I put on the simulator? If the OEM's are that expensive is it because they truly are built with higher grade metals that out perform out last or are we paying for name brand and same materials as the secondary market? I realize the stock one was probably CARB compliant. I'll look for the CARB label today.

 

I wouldn't spend any money in addition to the sim. unless you're looking to boost performance; if thats the case I'd put in a cheap high flow cat. if you're just looking to solve your CEL there's no need for anything beyond the sim. Yes, the factory cat that comes on your truck is far superior quality to 95% of what you'd find aftermarket, particularly in terms of reducing emissions. They are, however, a little more restrictive then some aftermarket high flow cats, and much more restrictive then steel core/racing cats. I put an aftermarket high flow cat in my 3rz and when the CEL came on I bought and installed the sim; which worked perfectly. Now i'm considering gutting my cat to boost performance, but i certainly wouldnt recommend that for your needs... you might want to unbolt and drop your existing cat; when i did this with a previous car i found that the honeycomb guts had broken and shifted in a way that had severly restricted airflow. shine a bright light through one side of the pipe and if you can't see it from the other side, it might be time to buy a new cat (go as cheap as u can cause you'll have a sim anyway, or gut your cat and bolt it back up to look stock.

 

As it turned out I did not need a sim. The magnaflow cat replacement that I ordered online from a popular retailer cleared the check engine light for code P0420. I mentioned in another thread that the previous owner never bothered to replace the gaskets on the OEM cat and I think that might have fried or contaminated the OEM cat somehow. That's too bad because I have read on this forum [from you and others] that the OEM's last a lot longer. The magnaflow is welded in and it has been a couple thousand miles now - still no CEL returning since the CAT replacement. When it fails again with P0420, I will remember to post the mileage that I got out of the replacement magnaflow CAT with the model number here.

NOTE: The muffler shop dinged me twice for labor - once for removing the gaskets and welding in the original OEM CAT, which did not clear the CEL and a second time for labor to weld in the replacement Magnaflow. I could literally see dollar signs in the muffler shop owner's eyes reflected off the sucker written on my forehead. I could use those dollar signs for my own welder and some practice scrap pipe.

 

Yeah, welding the original cat was a really bad idea. I would not visit that shop again. A leak would have to be extremely severe to trigger an OBDII code; this mechanic knew that welding your old cat in place of gaskets would not clear the code. Even if he thought that a leak was causing the problem, your flanges would have to be completely rotted for new gaskets to not work (which would have been much cheaper). Man it's too bad you bought the cat.; I thought I made it clear in my last post that you shouldn't (unless you're looking for performance). I put in a high quality aftermarket cat. and it threw at about 3500mi. If it throws a code on you try spacing the 02 gasket outwards to pull the sensor out of the direct exhaust flow, but this may require some custom fab, and if you can't do that yourself it would be cheaper just to get the sim. (Plus the sim covers you if your sensor goes bad, too.)

 

The leak from both gaskets failing was very severe and it was repaired halfway pretty before I bought it. Just enough to make me overlook it when I bought it. How about rethinking 3500+ miles with a Magnaflow cat? In fact, I am at 7500+ miles with the Magnaflow aftermarket replacement.

No P0420 codes have occurred since replacement. I like the SIM idea and your advice to keep the OEM cat on, but, for now, the after market Magnaflow replacement cat that I bought and had welded on is working just fine with original O2 sensors. I also liked the idea of a direct weld for other reasons beyond mechanical reasons. Although I do not know the shop owner who does my welding for me, I take Toyota pickups there after a referral that I received many years ago when we only drove pickups with 22RE motors.

NOTE: This is not a California compliant CAT that I used to replace the OEM CAT. If I remember correctly about what I read under the hood and the research that I did on my VIN, my truck was built in Canada. Please feel free to ask me to verify and confirm this information if anyone ever needs me to confirm for their own repair decisions.

 

Glad to hear that after all these miles, your cat is still working like it should, and keeping your truck CEL free.

 

Yep. Still working. Needs a muffler now. I am expecting the exhaust manifold to crack anytime based on typical 130K reports that I read but so far so good. This truck is really cooperating with me and my everyday+ dependable driver for point A to point B. It is saving my Silverado miles for pulling the boat only. I will not go back to a muffler shop ever again because I bought a welder. We have enough cars in family to justify a cheap flux core welder for exhaust repairs now.