LX470 Catalytic Converter (2 Viewers)

[2001LC]

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

You're more than welcome!

Remember: We must determine "why" a CAT has fouled or burnt up.

 

[DuckLN]

I’ve not crossed the cat failed bridge yet and Arkansas doesn’t perform exhaust testing so not worried about it.

If you remove or gut the cats will the engine run correctly?

 

[2001LC]

Follow proper PM and OM instructions, and you'll never likely cross that bridge.

If a CAT fails, don't ask how to get around. But ask why and correct.

CAT actually do help reduce pollution. I've driven internal combustion engine vehicles, all my life. So I can't cast stones. But I do, work to keep all pollution system working as designed and engine at peak performance. We all live in the same blue bubble.

 

[Tareq]

I’ve not crossed the cat failed bridge yet and Arkansas doesn’t perform exhaust testing so not worried about it.

If you remove or gut the cats will the engine run correctly?

My cats stolen maybe 4 years ago, so I welded pipes, no engine lights or any codes whatsoever! Noise is same as stock, but sounded like an F16 driving to the exhaust shop catless!

 

[Les Summer]

Number one, reason they burns up. "Bad MAF sensor". Will take out a CAT fast

Do you think it's smart preventative maintenance to replace the MAF sensor as precaution? I hooked up the Autel reader tonight to check as to why my fuel consumption dropped to between 9 and 10 mpg during my last 60 miles worth of trips. I thought my tank was going down quicker than normal even with normal city driving and running the heater. The live scan showed me 5.25 g/s on the read out after I got the engine warmed up and let it sit idle. I'm nearing 300k miles, and who the heck knows, this could very well be the original MAF sensor. I took a pic of it.. I have to check the FSM to see if there are any values given for the MAF, I'd bet a small coffee it does.

 

[2001LC]

Do you think it's smart preventative maintenance to replace the MAF sensor as precaution? I hooked up the Autel reader tonight to check as to why my fuel consumption dropped to between 9 and 10 mpg during my last 60 miles worth of trips. I thought my tank was going down quicker than normal even with normal city driving and running the heater. The live scan showed me 5.25 g/s on the read out after I got the engine warmed up and let it sit idle. I'm nearing 300k miles, and who the heck knows, this could very well be the original MAF sensor. I took a pic of it.. I have to check the FSM to see if there are any values given for the MAF, I'd bet a small coffee it does.

View attachment 3795236

Yes!
I've been seeing improved fuel trims, with replacing these old MAF sensors. Make sure to disconnect negative battery post clamp first. Wait at least 20 minutes to reconnect battery. If it was me; I'd monitor fuel trims (FT) before and after, also. I'm most interested in long and short FT. While cruising steady on flat HWY. at about ~2,200 RPM 65 MPH holding steady.

BTW: I see a vacuum hose going over the air pipe. I'll assume is one of the idle up hoses from vane pump idle up control valve, connecting to pipe on intake manifold. It's actual routing, is under air pipe. But works either way.

 

[Les Summer]

Yes!
I've been seeing improved fuel trims, with replacing these old MAF sensors. Make sure to disconnect negative battery post clamp first. Wait at least 20 minutes to reconnect battery. If it was me; I'd monitor fuel trims (FT) before and after, also. I'm most interested in long and short FT. While cruising steady on flat HWY. at about ~2,200 RPM 65 MPH holding steady.

BTW: I see a vacuum hose going over the air pipe. I'll assume is one of the idle up hoses from vane pump idle up control valve, connecting to pipe on intake manifold. It's actual routing, is under air pipe. But works either way.

Doing it today… thanks!

 

[Les Summer]

I bought my new MAF sensor from the dealer, and paid the premium for peace of mind. I tested out the old sensor according to the FSM. The temperature of my sensor I estimate to be approximately 75 degrees, which is the temperature in my apartment, and my ohm read out is approximately 1.8.

According to the FSM if the sensor temperature is at 68F this should result in an ohm reading between 2.19 to 2.67 ohms. I'm going to say my resistance reading is not correct, and the sensor is faulty.

 

[Lexdawg]

This is all very helpful,.
I have an 05 Lx 470 with 158k and I’m hearing the rattling sound like the cat is already bad . CEL is on and my me mechanic switched out O2 sensors several months ago and CEL went off. Now back on and throwing the cat code. I’m thinking given the noise the cat is done???. I don’t want to spend for the OEM part so thinking Walker ?? Thanks !

 

[MattyO]

Yes, would love to know what aftermarket cats people have used with success. I keep getting the P0420 code and it looks like I am going to have to replace cats

 

[2001LC]

Yes, would love to know what aftermarket cats people have used with success. I keep getting the P0420 code and it looks like I am going to have to replace cats

Yeah, based on what your stated to me in PM. I agree.

I've used Davico, since I was matching one already on. It's a blot on and clears most states reg. I've had on 5 years now, no issues.

 

[zipdoa]

I finally got around to pulling my cats today. Fuel economy is terrible and I'm throwing all sorts of O2 sensors codes.

Here's a quick peek at the honeycomb media prior to letting them soak. I'm going to try the circulating 160'F Citric Acid/Oxalic acid bath. I'll be running 4 new O2 sensors as well. Hoping this restores their functionality!

Kind of interesting to see the factory markings still visible in the honeycomb:

 

[menancyandsam]

Any tips on unbolting those cats. Only thing stopping me from trying to clean my cats is the fear of snapping or damaging the brackets.
I've dealing with a persistent P0420, which all new O2 sensors and cataclean did not fix.

 

[zipdoa]

Mine were pretty easy, just make sure you hit the bolts with penetrating fluid beforehand. I had no issues removing them - just dropped the back of the belly pan for better access to the upper 3 bolts.

Took me an hour.

I laid the pipes and filled them with lacquer thinner overnight. I shook the fluid a few times and changed their orientation to try and expose all of the honeycomb media to the fluid.

It definitely came out quite a bit darker/yellow/oily along with some soot, but I was hoping for a little more ‘evidence’ in the fluid.

I’m trying to figure out a large shallow plastic container that will fit both pipes. I’ll fill it with distilled water/oxalic + citric acid, and then circulate and heat the bath @ 160’F using an old Anova sous vide machine. Hoping to get that finished this weekend and I’ll report back again.

 

[zipdoa]

Acid bath in progress. I setup a pump to circulate the solution, feeding it directly into the cats. I'm using a pool heater to keep the water at 160'F. I'm really hoping this is enough to regenerate them.

 

[augustwest]

Any tips on unbolting those cats. Only thing stopping me from trying to clean my cats is the fear of snapping or damaging the brackets.
I've dealing with a persistent P0420, which all new O2 sensors and cataclean did not fix.

Had to hack mine off and replace with new nuts/bolts. There was no other way those little bastards were coming off.

 

[augustwest]

Acid bath in progress. I setup a pump to circulate the solution, feeding it directly into the cats. I'm using a pool heater to keep the water at 160'F. I'm really hoping this is enough to regenerate them. View attachment 3899166View attachment 3899165

Have you had a chance to reinstall the cats and test?

 

[zipdoa]

Re-install happens tonight - I'll update once I have a chance to drive it a while. Usually I'd get a P0420/P0430 within an hour.

 

[zipdoa]

Fresh hardware and it's all buttoned up. No more P0420/P0430 codes.

B1S2 voltage is high-flat (~0.96 V) while B1S1 lambda oscillates—exactly what you want from a catalyst with good oxygen storage.

B2S2 has a heater feed/ground issue that I'm going to chase down, at which point I can 100% test everything, but I'm optimistic the cats have been sufficiently regen'd. I'm really stoked - OEM cats are ~$1500USD/ea

Here's a breakdown of what I spent on this process:


~ $40 - 2 gallons laquer thinner
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~ $15 USD - 5kg citric acid
~ $15 USD - 2kg oxalic acid
- $35 USD - 25 gallons distilled water

- $30 USD - Large plastic bin
- $20 USD - 2000w pool heater stick
- $20 USD - 900lph aquarium pump
- $20 USD - misc hoses, t-fitting, hose clamps

= $155 USD for the acid bath kit ($65 in consumables)
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- $160 USD - genuine denso upstream o2 sensors x2
- $90 USD - genuine denso downstream o2 sensors x2
~ $30 USD - 10x exhaust studs, hardware, gaskets
@ rockauto

I did a s***load of research while working on this project. Here's the most common chemicals you could use to clean a 3-way catalyst

Contaminant Type vs Cleaning Agent Effectiveness​

Contaminant Type	Citric Acid	Oxalic Acid	EDTA (0.1–0.2 M)	Lacquer Thinner
Soot / Carbon residue	Mild	Mild	Ineffective	Strong solvent
Oil ash / Fuel ash	Good	Good	Limited	Excellent
Phosphorus (e.g. from oil additives)	Moderate	Good	Moderate	Variable
Sulfur contamination	Moderate	Good	Weak	Volatile
Lead / Zinc	Weak	Moderate	Very Strong
Calcium / Magnesium	Moderate	Moderate	Very Strong
Iron / Metal oxide dust	Weak	Good	Good
Coolant contamination	Good	Good	Moderate
Surface etching of carbonized junk	Slow	Moderate	None	Yes (solvent)

 

[2001LC]

Nice job.