Removed cats

I removed cats and put an exhaust on, also added extensions on back 2 O2 sensors. Still running rich and throwing the p0420 and p0430 code any thoughts

 

Yeah put the cats back on.

 

mmmmm bypass???? will trigger the O2 sensors to more or less think everything is OK.... unless you like looking at the CEL all the time....

 

Throw another anti fouler on

 

I tried the same and stacked bung extensions without help. I just got a single bank of high flow cats installed yesterday after 6 months of trying to win.

also: please don’t bypass your CEL engine light. I did this once on a f150 ecoboost (1st problem there) and the engine melted two piston skirts because it wasn’t reading correctly and giving me proper codes and wonky afr setpoints

 

Put them back. I messed around with o2 simulators with headers on my 2010 and it never worked right.

 

I'm going tomorrow to have this done on all 4 cats. I don't care about the CEL I will regularly run my system for codes ( I have a OB reader). What do you mean it's running rich? I have a huge MPG problem/engine performance at times is sluggish after a expensive tune up. I've tried just about everything now. In my situation it has to be the cats that are bad/clogged or something. I can't afford to replace the cats so I'm chopping them off. Can anyone recommend me a good simulator or just the ol spark plugs non fouler method? What should I do. Like I said I don't mind the CEL I will check it everyday if I got too

 

Here are 2 methods... I was going to hold out as some may get angry, but may help others.... Lotus is 1 method a defouler and the Celica is another method under post #116... I can't see the ocular pleasure on my end, may be because I'm at work but may show up on your end...

https://www.lotustalk.com/threads/e...r-installing-larini-de-cat.24630/#post-410777


https://www.newcelica.org/threads/c...ake-mil-eliminator.216641/page-6#post-5901754

 

Thank you black demon, In your honest opinion let's say I do nothing and leave the CEL on and regular run codes for anything new, will it really matter? Shouldn't the truck just run as normal? Someone was telling me it will mess up the ratio of air/fuel and start messing things up?

 

Also read on another tundra forum that doing nothing and leaving the CEL will be fine and not hurt my truck at all. Just gotta deal with the light being on and regularly check. I wanted to check here again before going through with it.

 

I wouldn't take the cats out. They are there for a reason.....ratio and back pressure for starters. Aren't cats a federal requirement?

 

State I live in doesn't do inspection. I guarantee you in my town you won't find a truck with cats lol except new trucks. I'm in a situation where I'm getting 8mpg and my truck is losing performance due to cats. I don't have the budget to replace so I'm kinda stuck between a rock and a hard place

 

realistically, no there is no issue if you left it as is... the result is what you're getting now "so so mpg"...... I live in Cali, so I technically don't have a choice HAHAHA....
You should run an AFR diagnostic to see if you are running rich or lean and find a better answer to your mpg issue...
but like you stated odds are the cats are clogged and cutting them off will improve your mpg some. I've never smogged my Tundra, but my Celica is a different story, because I dragged my feet, but will be correcting this error soon...

 

Yeah that sucks, I would love to live out in Cali though. I live is South Carolina they literally don't care if you burn a whole in the sky here LOL. Thanks for the info though. There is literally no benefit to me keeping them at this point. Just for kicks, where would I need to go to have a AFR diagnostic done? Toyota? Do most local shops have the machines to do these tests?

 

I would say borrow an obd2 that is able to do live data reading on short trim long trim fuel read outs, Heres a vid on how you can run these... gives you an idea of where you are more or less..... I thought about this recently as I was trying to chase down a lean condition on my Celica and it dawned on me that I didn't tightened the intake to the TB...

https://www.youtube.com/watch?v=pIJdCZgEiys

 

Awesome man thanks, I have like a $80 OBD2 reader maybe it can do this lol I will try this tomorrow before chopping the cats off.

 

yeah man knowledge is power... may be a simpler fix than a saw... but nothing a saw can't resolve quickly... lol

 

I have an O2 simulator from URD on my v8 4Runner, it's adjustable so I'd imagine with a little effort you could easily get it to work on the Tundra. Same deal, no emissions here and it needed new headers and I wasn't gonna pump out extra cash for cats when it doesn't need them. No noticeable difference in power from "lack of back pressure".

 

Thanks for the confirmation snivilous, you wouldnt happen to have a link to the specific one you bought would you? Everytime I look up these simulators I get overwhelmed with different kinds and really don't know which one is right or the best option per say for my truck.

 

Balck demon I know you got a answer for me, Which O2 sensor needs to be defouled? Do I need to defoul all 4 sensors? Or the ones closest to the rear? Or the ones up inside the truck? The name of each sensor escapes me. I'm about to get these things chopped off in 20 mins.

 

LMAO RIP! Hey like I said before though, I need these cats replaced and I can't fork out all that cash so they gotta go brother!

 

Only had a single o2 sensor go bad once my catless headers went on. No codes...

I have read that some extensions do not transmit the right voltage to get an accurate read. The extensions I have came direct from ARH so I never had to worry about it.

 

Lol so what are you saying? If your saying that removing the cats will damage or break my engine than that is completely contradicting everything I've heard from everybody on here and every mechanic I've talked too.

 

There's two sets of O2 sensors. The ones closest to the cylinders and ones after the cats. The ones closest to the cylinders produce a wave like signal to tell the computer if there's too much or too little O2 and the computer compensates. The ones behind the cats are looking for just O2 and their signals are usually more of a flat line. They are checking to see if the cats are removing the NOx and SOx from the exhaust gasses.

If the ones near the cylinders don't work the engine defaults to a preset fuel to air mixture (worse gas mileage). I'm not sure what the computer would do if it sees the cats not working. It could just throw a code or it could assume they are plugged and use more fuel to try and burn out the clog (or something else).

 

Hey Dr Al so which sensors should I try to non foul? All 4 or just the 2 after?

 

Usually when people run high flow cats they put adapters (anti-fouler or bung extension) on the downstream sensor. I think the same move would apply for your cat removal.

 

I'm sorry I don't know much about cats/O2 sensors. Are the downstream sensors the ones closer the rear. I see more that are kinda up inside the passengers side door. So are the down stream sensors basically after the first set of cats?

 

Hey guys I just got my baby back there are no check engine lights on so far and the cats have been removed. When can I expect the check engine light to come on? I don't think the battery has been reset yet