LX470 Catalytic Converter

[poetdereves]

I’ve read every thread in here about the P0420 code and have done almost everything to fix it except for replacing the catalytic converter. All new O2 sensors, air filter, oil change, replaced PCV valve, cleaned MAF sensor, cleaned throttle body, etc. I assume at this point whatever may have cause the cats to go bad is fixed, but the code is still on. Has anyone used aftermarket cats with success? OEM are ridiculously expensive (~$1,300 a piece). I live in a state with no emissions regulations, so I don’t need to pass smog or anything. I just want to find a different option that gets the job done and have my CEL light off.

 

[excessive]

i used a rockauto walker catalytic converter on another lexus vehicle (LS430) and so far it's been good. OEM is always best, but at least for that car, i dont care enough about it to buy OEM

 

[Petertn45]

I used the Davico 17194 from Rock Auto. Has worked fine without any CEL since December 2021. No regrets at all.

 

[GTV]

I've used Magnaflow

 

[zipdoa]

I'm going to do the subaru special method of removing the cats and cleaning them in Citric acid.... anyone else tried this?

 

[BullElk]

On my '06 LX, I used the spark plug fouler hack. It's been about 1.5-2 years and the CEL has come on twice. It used to come on regularly with p0420/p0430 codes.

 

[abuck99]

On my '06 LX, I used the spark plug fouler hack. It's been about 1.5-2 years and the CEL has come on twice. It used to come on regularly with p0420/p0430 codes.

O2 sensor spacers?

 

[BullElk]

O2 sensor spacers?

I think that is basically what they did but not called that. That hack on works on the model years where the sensor threads into the pipe, not the one with two rusted nuts on each side. There may be some spacer hack for that too but I am not aware.

 

[abuck99]

Got it - yes 02 sensor spacer for the threaded sensor-

 

[BullElk]

For example....

Dorman Products - 42009

Spark Plug Non-Foulers - 18mm Gasket Seat

www.dormanproducts.com

 

[augustwest]

I'm going to do the subaru special method of removing the cats and cleaning them in Citric acid.... anyone else tried this?

Did you try this? If so, did it work?

 

[menancyandsam]

I've heard a gal of laqcure thinner in half a tank then freeway driving to cook it off. Will clean the cat and clear the code.

 

[Malleus]

...and cook your plugs.

 

[2001LC]

If CAT is burnt up, they must be replaced.

Before replacing a CAT. We must find out and correct, what upstream issue, cause the CAT to go bad in the first place.
What I've found is the number one killer of CATs. That with result in them burning up, relatively fast. Bad MAF sensor! This can result in a very rich condition, dumping raw fuel into CAT and igniting them.

Other causes:

• Coolant. Typically from head gasket leak, due to overheating warping heads.
• Impact to the CAT, busting the CAT material.
• Prolonged idling. CAT below optimal operating temp, fouls them.
• Prolonged, foul running engine. In need of a tune and or has cylinder compression issues.
• Driving cold engine short distance, shut down until cool again and drive short distance again. Repeating this daily. Never reaching higher RPM for prolonged periods (typically HWY drive). Fouls A/F & o2 sensors and CATs.
• Bad or fouled o2 sensor.
• Engine running excessively rich.

Cleaners:
I tried Cataclean once, on CATs that was not burnt-up. So seemly clogged. I ran 44K, then Chevron Techron in separate full tanks of fuel first. Then Seafoam fog into intake manifold. Then Cataclean with only 4 gallons of gas in fuel tank, HWY run at ~4,500 RPM, until nearly ran out of gas (carried spare gas in a can). Didn't help! But I did see the cleanest intake ports of heads, I'd ever seen.

Cataclean or Sledge Hammer. Are basically paint thinners with a few additives.

In the 06-06 VVT, we can read CAT temps. I've found they reach max temp, around 4,500 RPM. I've run over red line (oops), for over ~20 minutes on HWY. CATs didn't get much hotter then I saw at 4,500 RPM.

~2,500 RPM, is where CAT reached there optimal temp.

Personally. I never do anything to fool a CAT, ECM or disable any pollution control devices. I correct the issues and or modify to improve pollution control devices.

S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!

We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...

forum.ih8mud.com

 

[Goose17]

I've bought a 4Runner and Tacoma with all 4 Cats stolen and replaced with Walker from RA and they have run great and passed AZ emissions testing. You can try an 'Italian Tune Up" and run the vehicle on the highway with OD off at about 4k RPMs and try to burn off the build up. If that doesn't work, then just get a Walker replacement from RA for under $350. They are easy to replace on this vehicle, I removed them when I replaced the 02 sensors.
I wouldn't try to bypass anything. Just going to throw off the vehicle's computer.

 

[Les Summer]

Cleaners:
I tried Cataclean once, on CATs that was not burnt-up. So seemly clogged. I ran 44K, then Chevron Techron in separate full tanks of fuel first. Then Seafoam fog into intake manifold. Then Cataclean with only 4 gallons of gas in fuel tank, HWY run at ~4,500 RPM, until nearly ran out of gas (carried spare gas in a can). Didn't help! But I did see the cleanest intake ports of heads, I'd ever seen.

So you are saying there's a chance the Cataclean works?

 

[excessive]

you could try they old method

all you need is a fried, a gallon of diesel, and a salad bowl

 

[2001LC]

So you are saying there's a chance the Cataclean works?
View attachment 3789823

If CAT, not burned up! It's worth a try.

Tapping on CAT, with heel of hand or rubber mallet. Is it a solid sound (good), or sound like material rattling (burned-up) around.

To clean CAT while driving, with fuel tank additives. Davico (aftermarket CAT) recommends Sledgehammer others use lacquer thinner. Google and you'll see many ideas on how to clean a CAT with fuel additives.

We must determine why a CAT failed. So we don't damage a replacement CAT.

Number one, reason they burns up. "Bad MAF sensor". Will take out a CAT fast
CAT will overheat, if fuel mixture to lean.
CAT will burn up if fuel mixture to rich.
Bad compression, dump raw fuel or oil.

CAT will foul:
Prolonged idling (read your OM)
Coolant.
Oil (bad oil rings, valve guides & seals, etc)
Raw fuel or oil.

If fuel or oil fouling a CAT. That carbon can then ignite, burning up the CAT.

Clog CAT. One which has built up sludge, but not ignited. Flood waters. etc.

Nest or flooding clogging exhaust pipe. Typically get both CAT DTC at same time. Exhaust back pressure gauge is useful tool here..


Borescope is very handy to inspect CAT through A/F or O2 sensor port.
Burnt-out CAT, from bad MAF sensor.

 

[augustwest]

you could try they old method

all you need is a fried, a gallon of diesel, and a salad bowl

I had success removing the cats and running a solution of distilled water, oxalic acid, and citric acid through the cats for about 6 hours.

https://pubs.acs.org/doi/10.1021/es052310t

P0420 - Catalytic Converter Citric Acid Bath!

www.subaruforester.org

Cat Cleaning Citric & Oxalic Acid. CO Emissions

Emission tested the 94 LC 417,000 mi and got a FAIL. 1st test O2 unplugged = 6.8 NOx 2nd test plugged in old O2's and added 1 gal denatured alcohol to 5 gal gas 7.3 NOx I checked the temp of the cats after hwy driving and the cats were the same temp as the exhaust pipes off the manifold so...

forum.ih8mud.com

P0420 / P0430 and a "Hail Mary Pass" (the...

www.tundrasolutions.com

 

[Les Summer]

@2001LC thanks, I was thinking of using cataclean / sledgehammer as a preventative measure..