No, probably, and no, respectively.

Does trying to pour a flammable liquid into the high-pressure blast of hot exhaust gasses escaping from the opened sensor bung sound like a good idea? If you're very lucky, the engine will simply stall without the sensor input. If you're less lucky, you'll be a news article.

 

If it was so easy then everyone might do it. You are the first that I have heard of, going where angels (engineers) fear to tread.

Edited to add later: Part of my SCCA ‘career’ was a National Licensee in Flags & Communication. I was invited to work emergency services at NASCAR Talledega but I had to qualify as Georgia State Fire Control Technician. Most of that training was with alcohol fires that, like acetone, are invisible. A technique that I learned and recall was to approach an incident possibly involving fire with a powder extinguisher and discharge it high towards the car in order to see the powder lofted by the heat of the invisible flame.

Maybe this is where I learned to hate the smell of gasoline - in addition to having it run down my arms while working on fuel systems overhead.

 

Most of that training was with alcohol fires that, like acetone, are invisible.

Nope. Acetone burns blue in small quantities, but yellow with larger amounts where evaporation causes incomplete combustion.

 

If Zeichen & Uncle Doug have not convinced you that it might be a bad idea, maybe this guy will!

Jay Leno Shares the Shocking Details of His Burn Accident: 'My Face Was on Fire'

Jay Leno shares the shocking details of the Nov. 12 car fire that left him with 'severe' second-degree burns

people.com

 

A favorite internet correspondent and role model was Alan ‘Uncle Al’ Schwartz, a very accomplished and brilliant organic chemist. He survived an organometallic explosion and fire on his workbench. He was disfigured, perhaps lost some fingers, but survived for having clenched his jaw shut and squinted hard his face.

I ‘helped’ him with his challenges to the Equivalence Principle (weight mass is equivalent to inertia mass). Had he won the Nobel Prize in physics then I would have introduced him. A tip o’ the hat to Organiker, I hope that you are well. This is where I learned the Machian Principle. https://en.wikipedia.org/wiki/Mach's_principle

 

Or to put it more precisely, "You want to do what?!!"

 

Seriously, stay away from highly flammable liquids. Not quite sure why that option even entered your mind.

Liqui-Poly makes a catalytic cleaner liquid along with an applicator high-pressure sprayer. They whole will set you back approx $500. There are other manufacturer that provide other catalytic converter cleaners that work with various degrees of success (from zero to somewhat).

Some YouTube Indian idjit uses carpet cleaner with a high pressure hose - yeah, don’t do that.

You can also look into one of the SEAFOAM products. Again YMMV.

 

That code means the catalytic converter is degraded to a point where it isn't working. It doesn't mean it's dirty. And NO it's not safe to do that. Generally you need a new or 2nd hand cat when that code appears.

 

+1. I'm helping a friend trouble shoot this exact issue on his X3. Unfortunately, he had already put four cans of catalytic converter cleaner into his fuel tank and proceeded to drive to Florida from Canada.

His car started going into limp mode upon his return trip. After getting hosed by a Fla dealership for the replacement of the pre-catalytic sensors, the dealership surmised that both catalytic converters needed replacement.

He decided to try replacing the post catalytic sensors first but took the headers off the engine rather than work on them from under the car. This is what he found:

 

Posted without comment:

Amazon.com : catalytic converter cleaner

 

Since you asked (meaning I would not do this), if you have no emissions testing in your state, you could look into deleting the cats. The issue then is programming the sensors for the omission. That’s way above my talents.

 

It is still illegal at the federal level to modify emissions systems, regardless of state requirements.


You didn’t just buy a BMW if money was of any concern, did you?

 

BTW, Acetone is not alcohol.

 

I have used a product called Cataclean (about $25 for 16oz) on my e28 twice. It worked great, 90%+ improvement in California emissions test. YMMV.

 

thanks, i used this cataclean and the check engine light has been gone for about 500 miles now.. passed emissions. sry guys im new to forums and didn't know how to find this thread again

 

Do What!!

 

I'll get the marshmallows

 

What you were planning on doing was not only a bad idea, it was a very, very, very bad idea !!

 

 

You guys do realize there will be no more posts by the OP, nor any more OP's comments on this thread, right ?

 

Of course we do 🤣. But maybe it will give a clue to others why it's a bad idea.

 

lacquer thinner will not dissolve harden carbon.

 

Troll perhaps??? Looking for some fun???

Good looking cat though, looks like our Gato!

Acetone does evap quickly but depending on how much you poured in and how long you waited I guess would depend on the excitement factor. I would recommend using the remote start feature and a good distance from any structure. LOL

 

Sure if you want a quick free trip to the moon pour lacquer thinners down your cat and strike a match!

 

Here we go...so I have an 2009 X5 bought it at 118k, a week of driving the car, the famous cel came on and funny enough it was the cats. I took the car to previous owner's mechanic and he said yeah this car needs cats and cel been on and off since 100k, we tried cleaning them, etc...so I started digging online to see how to clean them because in California those suckers cost $2500 and aftermarket are not allowed per state law. I tried cataclean , oxycat, CRC..seafoam, you name it, with no luck! I even got a endoscopic camera and plugged it in o2 sensor hole to see if the honeycomb melted or broken and sure enough I could see some degradation in the center and some melted spots...anyways long story short, I kept looking online and saw tons of diy videos how to clean cats and nothing that I didn't try....last hope I googled on how to clean platinum and I came across a study article from Europe I guess where scientists tried oxalic and citrus acid to clean cats under certain temp, bla bla bla..however to do this job, I had to take the cats out and cook them for about 8hrs in acid. As I had to fix the stupid oil pan leak that requires to take out the complete suspension and subframe which gave easy access to take the exhaust out. So I cooked those suckers per the article and even kept them overnight in the solution. After 2 days everything was assembled, reset all codes on the car and took it for a long drive. Fast forward, car has 145k on it now. Cats are clean as a whistle no cel light, passed smog, no more engine hiccups or stalls. Car is running great...bottom line whoever says cleaning cats is nonsense, well he is full of crap and wants to steal your money. Project costs less then $50 and you will have reenergized cats at over 90%. PM if interested on how to do the diy or just google, there's actually a guy posted on YouTube how he did it....sorry for the long post..

PS: if this doesnt work, look into a vacuum leak and also change the eccentric shaft sensor!

 

Here we go...so I have an 2009 X5 bought it at 118k, a week of driving the car, the famous cel came on and funny enough it was the cats. I took the car to previous owner's mechanic and he said yeah this car needs cats and cel been on and off since 100k, we tried cleaning them, etc...so I started digging online to see how to clean them because in California those suckers cost $2500 and aftermarket are not allowed per state law.

I didn’t know about the CA law. A few years back (in CA), my commuter car (2001 Prizm) failed the cat test, probably from the well know oil ring blow by on the Toyota engine. Found a new replacement CAT on line (non OEM), installed it, and took it back for a retest. It passed. I don’t think they looked to see what was there.

 

Wow that's an interesting post and thanks for sharing. Not pissing on your BBQ here, this seems like an honest answer and not a "well it was on the internet so must be true" response.

A couple comments/questions:

- How difficult was it to remove the cats? I consider myself a pretty decent DIY'er but when my V8 Explorer needed cats it looked like a major PITA so took her to a good local shop. But yeah still was not cheap even for the Ford.

- Second your camera method seems a bit unscientific to determine if the cats are damaged beyond a condition that can be cleaned. I have no data but I suspect by the time the CEL light comes on indicating a cat problem the damage has already been done and need to fix the problem that damaged the cats first and then replace the cats. Obviously it worked for you and if you have the skills, have the time and (what you do with that acid when done with it?) It's worth a shot. But if not; I am not even sure many independent local shops would even attempt this. And again I think the success rate is pretty low as if the cats are severely damaged no amount of cleaning will fix them.

 

1-Its pretty easy not a big deal, with all due respect i would never take a german car to an local american shop 🤪, they dont speak same language and for sure knows nothing about german engineering, bmw have good access in the engine bay and if you have ista it will guide step by step.

2- what i meant by using the camera is to see if the honeycomb is disintegrated or melted or broke, it’ll be pretty clear and obvious to see that, if they are intact and you see no cracked parts laying around, then your chances of cleaning them is high.

All in all is a full day job,. if you know how to throw a wrench you’ll be fine, i dont even consider my self a proper DIY guy, but hey worth the try. Oh when your done with acid mix, throw it in the backyard and rinse with the hose 😁

 

Is that really a state law that aftermarket are not allowed??? How do you enforce that? I guess they hold the shops responsible to only install OEM replacements??? Certainly can't stop a DIY from installing an aftermarket, like above, and as long as it passes you are good to go. No way are the inspection stations getting under every car to see what is stamped or not stamped on a Cat??? Yes/No? Not that I really care as I don't live in CA just curious.

 

If you look at an aftermarket exhaust catalog, such as Walker, it will say something like "not for sale in California" or "not for use in California".

The issue is that the catalytic converter only has a minimal amount of the required precious metals to function. Typically the element might only last 2 to 3 years or less, especially if engine is blowing oil into the exhaust stream . So, while the car will pass a smog test immediately after the replacement is installed, it's unlikely to pass in two years or less depending upon how bad the blow by is.

Since the whole point is to ensure that the vehicles on the road are producing minimal pollution, the vehicle inspection stations do indeed get underneath the vehicles to check for tampering and less than compatible parts. They will fail a car for that even if it does pass the e-test.