Think I may need to replace Catalytic Converter on my 2003 Taco

Any videos on how to install a 2003 Toyota Tacoma Catalytic Converter? Also which aftermarket Catalytic Converters that are cheap would you recommend? I am going to have an inspection done tomorrow and I think they will tell me my Cat needs to be replaced. I would like to attempt it myself. Looks like a bolted on Cat. Here are some pics. If you notice in the last pic there is a bolt missing on one corner of the Cat. Would that throw a P0420 code?

 

That is for sure your p o420 issue. fix the air leak and it will go away.

 

That bolt only holds on the heat shield. It won't cause the 420 code to throw.

Most likely us the gasket on ends of the cat.

 

Any idea what size nut and bolt that is off hand?

 

Those flange bolts are 3/8". They don't need to be metric. Most likely they will twist and break when you try to remove them.

When you get new bolts and gaskets and clear the code, you still won't pass the emission test tomorrow. You need several days of driving to clear the stored code. I wouldn't even schedule an inspection for at least a week.

 

I had this issue a few years ago. I bought Magnaflow cats and it cleared for about a week and came back. Toyota’s are finicky w/their catalytic converters, I bought an o2 sensor simulator and it cleared my CEL.

 

Probably an air vacuum leak or a bad 02 sensor.
I have 600,000 miles on my original cat.

 

What is an o2 sensor simulator and how do you install it? Thanks.

 

Will the mechanic tell me exactly what the cause of the CEL P0420 during the inspection? Whether its a bad Cat, o2 sensor, exhaust leak etc?

 

It depends if he's an honest mechanic or not like I said it could just be a vacuum leak but might be a faulty hose that could cost you $10 or he could tell you what's a Cat that cost you $500 or an 02 sensor 100.00

 

Well I cleared the code before I went there. Which I knew it wasn't gonna pass. Sure enough it didn't. I told him I had cleared a code. He said he couldn't tell me what was wrong because I cleared the code and had not driven it far enough for it to completely clear. lol. Guess you should never clear a code before getting an inspection.

 

Not decent under there, sorry but that’s the truth. You definitely need to pair up with a good welding /repair shop and get rid of those rusted tubes and put some good flanges on the exhaust and it will seal for another 20 years. In Ca they might flunk you on visual alone! Too bad we live in a world that requires this shit on our trucks because big corporations honestly put out more pollution than our vehicles do if properly tuned. The cats are probably for fine, bang on them with a plastic hammer and if the cat doesn’t rattle chances are they are good. You have a bad air leak just by looking at the pics, all at the flanges, they look like they were altered before and didn’t create a good seal.

 

It tells your ecu there is no problem coming from your catalytic converters. I think they can still detect engine codes even with an o2 sensor simulator. All it does it clear the check engine light. Here is one for the 5VZFE (6 cyl)

https://www.urdusa.com/urd-rear-o2-simulator-5vz-fe-3-4l-v6/

 

Your o2 sensor wire comes from the cats and runs up under your passenger seat. You’d unplug the o2 sensor under the seat and plug the sensor simulator between both plugs.

 

I had my cat replaced by a shop they used a cheap one and it lasted less than 10k miles. P0420 code now that will clear then come back after a day or two. I know a guy that buys used cats, he said they give $6 for a aftermarket because there is almost no platinum etc in them. A good quality used cat is worth $50-150.

 

Ok. So I tested both the rear and front Cats with a digital temp gun. I pointed the gun at the right side of the Cat on the pipe and on the heat shield. I then tested the left side of the Cat near the gasket and then the heat shield. Looks to me the temps are about the same for the rear and the front Cat. Tell me if I am wrong? That is not good right? Should be a 100 degree diff from one side to the other right? Here are my videos. One is the rear Cat and the other is the front Cat.

 

The P0420 code takes a while to set. It sounds like you have a OBDII scanner, if it has the capability to check for "Smog Ready" I would monitor it all the time. When I have a trouble vehicle like yours I will drive it around late at night to clear the monitors and get it smog ready. When it is ready for smog I drop it off at my smog shop immediatly. I am first person there in the AM and let it warm up in the stall or on the dyno. After it passes smog now you have 2 years to fix it because if it truly does need cat(s) its gonna take you that long to save up the $ for replacements.

 

If it feels like it's running normal, but only has the CEL, it doesn't need cats.

Also, if the exhaust does not smell like a trash fire, the cats are still good. The issue is going to be something less expensive.

 

It's a thing that won't pass inspection...


I've never heard of using temps to "test" a cat before either.

the 0420 code can also be your O2 sensors or an exhaust leak, I'd go there before replacing a $600 cat.

 

https://youtu.be/3w-FrjMFKvs