I have a catalytic converter question.

[Ducati996]

I have a catalytic converter question.
I acquired a 2004 Mitsubishi Endeavor with 180000 miles that had ignition issues (misfire) during a cross country trip prior to my purchase. Two ignition coils were replaced which resolved the skipping but the check engine light came on code (PO431) Warm Up Catalyst Efficiency Below Threshold (Bank 2).
My scanner showed all 4 O2 sensors were operating properly.
The vehicle runs great, good acceleration & power and gets 20/25 mpg so the converter does not appear to be physically damaged (restricted).
Looking for information to positively identify the cat as being bad I came across a you tube video by Scotty Kilmer that said you can save some cats by removing and soaking in laundry detergent for a day or so and/or add 1 gallon of lacquer thinner to a ½ tank of gas to eliminate the code.
He said he has been doing this for over 30 years.
There were many posts verifying this worked so being pressed for time and $ to pass an emissions test I decided to give it a try.
I added the lacquer thinner and drove the vehicle with my scanner attached. At approx 40 miles the light went out and no codes were stored.
I then drove to the inspection station and got my sticker.
I then topped up my fuel tank and within 15 miles the check engine light came back on, PO431 again.
My next step will be to remove and soak the converter as described to see if that permanently eliminates the code.

My question; what does the lacquer thinner actually do to the combustion process that eliminates the code?
What does soaking in detergent do?
Ducati996

 

[eljefino]

I find it hard to believe he's been clearing codes for 30 years when OBDII has only been around for sixteen.

 

[MrCritical]

Originally Posted By: eljefino
I find it hard to believe he's been clearing codes for 30 years when OBDII has only been around for sixteen.



This.

 

[Dakota1820]

i think he meant he has been cleaning them for 30 years. uhmm how to verify a cat failure . if its not rattling or clogged you really cannot tell unless you check your inlet and outlet temps should be around 100 degree difference. i would clear the code and make sure everything is working right. good fuel pressure and good spark if its running tip top and the light comes on again your cat is bad. but a car with a miss or anything can trigger the cat efficiency code.

 

[LeakySeals]

The soak "works", never tried the thinner. The thinner is supposed to superheat the cats, burning off more material. If all is fine, and your passing emissions, consider a $6 spark plug anti-fouler between the pipe and the rear 02 of bank 2. Cuts down the gasses passing over the sensor, lights out!

 

[mechtech2]

Good luck 'just' removing a cat do perform a silly procedure.
A royal pain.
If you have it out, replace it.
The anti fouler trick requires 2 foulers stacked, with the top one drilled out for O2 clearance [for the SECOND sensor only]. It works.

 

[JHZR2]

Working with precious metals like in a cat converter requires a lot of nasty chemistry - acids and/or halogen gases. Nasty, nasty stuff...

Want to clean metal from a sulfide or phosphate? Perhaps one could reduce to metal in a hydrogen environment, but likely not something that the average user has around.

So scrubbing detergent bubbles???? LOL. Perhaps as a degreaser on a catalyst that has a lot of oily residue on it.

Thinner burning the catalyst? Has anyone actually looked at the autoreduction temperature of Pt, Pd and Rh sulfides to metal or some other functional form?

 

[MarkM66]

Originally Posted By: mechtech2
Good luck 'just' removing a cat do perform a silly procedure.
A royal pain.
If you have it out, replace it.
The anti fouler trick requires 2 foulers stacked, with the top one drilled out for O2 clearance [for the SECOND sensor only]. It works.



Bingo. Try the anti fouler trick.

 

[Kruse]

Originally Posted By: MarkM66
Originally Posted By: mechtech2
Good luck 'just' removing a cat do perform a silly procedure.
A royal pain.
If you have it out, replace it.
The anti fouler trick requires 2 foulers stacked, with the top one drilled out for O2 clearance [for the SECOND sensor only]. It works.



Bingo. Try the anti fouler trick.


I think we can all agree that the stacked anti-fouler spark plug adapter works....until the Barney Fife emission inspector sees it. Yes, this will probably make the check engine light go out, but the OP needs to know that he may still need to buy a catalytic converter in the future when the emission inspector sees it and can't keep his/her mouth shut.

 

[JTK]

How's it going Duc!

The only thing I figure the quack chemistry is doing is fooling the ratio between the up and downstream O2 sensors just enough to put the light out for a short period.

Like said, there's just not enough precious metals in automotive CC's, nor are they built to bring them back to life.

I'd imagine a stock CC assembly would be mind-bogglingly expensive. For a Bishi with ~180K, I'd personally go the "spark plug anti-fouler" route like suggested. I highly doubt it's even close to a gross polluter, it's just not "seeing" fewer O2 molecules on that downstream sensor.

Joel

 

[MarkM66]

Originally Posted By: Kruse
Originally Posted By: MarkM66
Originally Posted By: mechtech2
Good luck 'just' removing a cat do perform a silly procedure.
A royal pain.
If you have it out, replace it.
The anti fouler trick requires 2 foulers stacked, with the top one drilled out for O2 clearance [for the SECOND sensor only]. It works.



Bingo. Try the anti fouler trick.


I think we can all agree that the stacked anti-fouler spark plug adapter works....until the Barney Fife emission inspector sees it. Yes, this will probably make the check engine light go out, but the OP needs to know that he may still need to buy a catalytic converter in the future when the emission inspector sees it and can't keep his/her mouth shut.


One thing I would do is spray a little exhaust colored hi-temp paint the them so they don't look so obvious.

I asked a local shop, smaller shop, if this type of thing would fail the inspection, and he had never even heard of it.

 

[javacontour]

Unless they do a physical inspection, most places won't pick up the anti-fowler trick.

In IL, I think they just hook up a computer to the OBD-II port and if all tests have completed and no codes, you pass.

Pre-OBD-II cars are no longer emissions tested in areas that require testing.

 

[LeakySeals]

Originally Posted By: Kruse
I think we can all agree that the stacked anti-fouler spark plug adapter works....until the Barney Fife emission inspector sees it. Yes, this will probably make the check engine light go out, but the OP needs to know that he may still need to buy a catalytic converter in the future when the emission inspector sees it and can't keep his/her mouth shut.
In MA we have very strict inspections. They rejected me for my license plate not being reflective enough. They have never looked underneath the car, never lifted it. Dont think the inspectors would know what it was even if they did. Looks like part of the o2 sensor. Most are way underneath, hard to see. Its been 2 years, all blended in now. In my case, Toyota has the range for catalyst efficiency CEL set at 95% (almost new), far exceeding the MA emission standards so it passes emissions with flying colors.

PS: a lot of the online DIY antifoulers use 2. One is enough if you drill the hole smaller than 1/2 inch, just enough for the tip to stick out, real tight. 1 is not noticeable at all

 

[mechtech2]

Only one anti fouler does not get the second O2 sensor out of the way enough.
It might if you are lucky and it already works somewhat.

 

[Ducati996]

Good luck 'just' removing a cat do perform a silly procedure.
A royal pain.
If you have it out, replace it.
The anti fouler trick requires 2 foulers stacked, with the top one drilled out for O2 clearance [for the SECOND sensor only]. It works.

I started my working career as a mechanic working on BMW, Mercedes & several other makes then went to big industry to make real money. I have a complete garage with lifts so this is not a silly procedure with cats costing $300 to $800.
I'm working on understanding current auto emissions so I can save myself headaches & $$$. I have referred people to others when they had emission problems but my current problem forces me to understand it to help myself.
I do not want to install a new cat if I can beat the system.
It’s hard enough to survive keeping vehicles in safe running condition let alone dumping several hundred dollars on something that does not affect the operation of the vehicle at least in my case.
This converter is not that hard to remove (for me) so I will play and give it a try.
What I learn may help others on this forum.
90cummins

 

[mechtech2]

I still say it is a silly procedure.

 

[mattd]

Originally Posted By: mechtech2
I still say it is a silly procedure.


I agree. Its not really worth the effort trying to revive a cat with that kind of mileage thats already throwing efficiency codes. I do this for a living as well, and would not bother on my own vehicle.

 

[paulo57509]

The OP most likely rides a Ducati 996. He has probably experienced the flaking rocker arm issue and had to replace most if not all of them. Hopefully, the rockers didn't wipe out the cams. Because of this, he is now broke and has to find creative ways to be able to afford food.

I've been there and done that with my 748.

 

[lexus114]

Originally Posted By: mechtech2
I still say it is a silly procedure.



Well, for someone like myself who doesnt have access to a lift. It would be kinda stupid to try and revive it by going through all of the [censored] to get it off. but for this person, who has a lift (or access to one anyway) if he can save himself $800.00 for a new oem cat, why not try?

 

[andyd]

The original cats are better the after mkt ones. If you can rescue the original , why not?