Exhaust Question(s) - Toyota Nation Forum : Toyota Car and Truck Forums

haux · 12-12-2009, 05:23 AM

Ok, so the P0420 came back after I changed my O2 sensors. I was told this could mean two things, 1) exhaust leak, 2) bad rear catalytic converter.

It was recommended that I check all the flange connections for leaks before replacing the catalytic converter.

Here's my thought. I recently just put on a TRD muffler. The old nuts for the flange connection had to be sawed off. I am certain this will also be the case for the other flange connection(s). So "checking" them, unless a leak is absolutely obvious, will be a time consuming and extremely aggravating task. Because I'd have to saw off those nuts, get the bolt/stud out SOMEHOW, replace the gasket, and reattach it with new bolts/nuts. Sawing isn't even the big thing. Getting those old bolts off will be near to impossible. They'll be rusted to the flange.

Also, in a recent thread, I read that a flashing check engine light may mean that the engine is misfiring enough to damage the catalytic converter. A number of months ago I had to drive 100 miles with a misfiring cylinder.

Could this have damaged the catalytic converter? This P0420 code is very recent. I can't recall if it popped up before or after that incident. May have very well been after, in which case it may be related.

So what should I do? Replacing JUST the converter means taking it to a muffler shop/mechanic and get some welding done. A new catalytic converter with that front pipe is $800 from the dealer. And that's ONLINE, so shipping will be killer too. Might end up being the same total price as from a local dealer. The mid pipe is only $180 plus shipping, or more with no shipping from a local dealer.

Also, in another thread, I've read references to a TRD "exhaust." What is a TRD exhaust? Just a TRD muffler, or is an ENTIRE TRD exhaust system? In which case, what's so different about it (other than the muffler) from a stock exhaust?

Are aftermarket catalytic converters with the attached piping ok?

Some suggestions on what I should do are appreciated. Specific questions are bold.

Kenny_McCormic · 12-12-2009, 09:48 AM

You will see carbon where a leak is present.

RU2CHKN · 12-12-2009, 10:02 AM

Are you sure you bought the right oxygen sensors for your vehicle? Cuz you could've gotten california emission sensors instead of fed spec sensors that might play a part in the code. That's what i've heard.

PortugalFocus · 12-12-2009, 11:29 AM

Go to a muffler shop and replace the converter. If you drove that far with a misfiring cylinder that converter is likely toast. Is there good back pressure? is the car hard to accelerate on the road or while in "Park"?

The TRD Exhaust is just a muffler that is bolted on. On of the 4Gen guys just put one on a few days ago, it's a recent post. That will do nothing to solve you problem though.

Is the exhaust overly loud? do you hear a leak? jack the car up or put it on ramps and look for a leak. There will be soot where a leak is present if you can not hear it.

Good luck.

the_professional · 12-12-2009, 11:44 AM

taking part a rusted exhaust is fun. just saw and hammer out the rusted crap.

but, I doubt a little leak will cause a code to pop up, you would hear the exhaust leak.

haux · 12-12-2009, 12:57 PM

Quote:

Originally Posted by PortugalFocus

The TRD Exhaust is just a muffler that is bolted on. On of the 4Gen guys just put one on a few days ago, it's a recent post. That will do nothing to solve you problem though.

Yeah, I put a TRD muffler on. I was just wondering if if there was more to that exhaust system, or just the muffler. But I get it.

My purpose asking about the TRD exhaust, in case there was more to it, is that if I'm going to spend a long time working on those flanges, I feel like I should be replacing something, rather than putting an old rusty part back on. The midpipe is fine, rust-wise. No holes or anything. I guess I'd be ok not to replace that.

Alright, so let's say I get a new catalytic converter, but I don't want any welding involved. I'd rather buy one already with the front pipe.

I don't think I'll go with RockAuto because of shipping. But the RockAuto brands are Bosal and Walker. I've never heard of these names. Anything to stay away from?

Chris Crash · 12-12-2009, 01:06 PM

Don't need to weld or have the front pipe!

Just slide one over the other and clamp it.

That worked for me when I replaced my resonator with a cherry bomb (poor choice)

bmxr4life87 · 12-12-2009, 02:55 PM

What part of oklahoma do you live in? If your close enough to tulsa I could offer a helping hand

haux · 12-12-2009, 10:48 PM

Quote:

Originally Posted by bmxr4life87

What part of oklahoma do you live in? If your close enough to tulsa I could offer a helping hand

Tulsa. Woodland Hills area. PM'd.

91Cress · 03-12-2010, 11:29 AM

Not sure if this should be same thread. Doing Census work I separated the exhaust at the two flanges. i looked under last night, can move it, the separation is front of the two flanges. There is a small section of pipe that is about 2 inches or so long to the AFT of whatever that is--muffler, cat converter?--with a bit of a lip on it. The AFT part of the exhaust w/the two flanges is just hanging there, well attached on to the rest and on out the rear.

I can't see too well as it is not jacked up.

Can I reattach the pipe somehow to the flanges? I made an appt to repair it before I looked at it for an auto shop 24 miles away (the nearest muffler shop is 2.5 hr drive) but want to know before I go what the problem is and how to fix it.

I was trying to tell from the threads here, but my problem is different. Didn't have any problem w/leakage before.

haux · 03-12-2010, 11:16 PM

Quote:

Originally Posted by 91Cress

Not sure if this should be same thread. Doing Census work I separated the exhaust at the two flanges. i looked under last night, can move it, the separation is front of the two flanges. There is a small section of pipe that is about 2 inches or so long to the AFT of whatever that is--muffler, cat converter?--with a bit of a lip on it. The AFT part of the exhaust w/the two flanges is just hanging there, well attached on to the rest and on out the rear.

I can't see too well as it is not jacked up.

Can I reattach the pipe somehow to the flanges? I made an appt to repair it before I looked at it for an auto shop 24 miles away (the nearest muffler shop is 2.5 hr drive) but want to know before I go what the problem is and how to fix it.

I was trying to tell from the threads here, but my problem is different. Didn't have any problem w/leakage before.

Is the question about whether you can re-attach a pipe to a flange? I didn't understand part of this post.

I imagine it would require some welding.