Aftermarket vs OEM catalytic Converters

[William_Wallace]

Yea I’m gonna replace with dealer parts I just priced them. I plan on drive through winter then in spring definitely replace. I’m have been trying to think if I did anything to contribute. I did spray Crc valve cleaner through the throttle body and ran chevron through gas tank every so often. Over the years I also put marine Ashless 2-stroke every once in a while during winter. 1 oz 5 gallons couple times a winter.

have always done this in my previous gas, diesel, small engine without a problem,

I may unscrew the upper 02 sensor and experiment with brake cleaner soaking the honey comb down. I’m gonna decon it!


there is an epic thread over a 10 year period on bob the oil guy about marine ashless 2-stroke running in gas engines it’s an interesting read but it may very well have cause problems with my cats

[Setec Astronomy]

Shades of Marvel Mystery Oil. Don`t take this the wrong way, and I`m sure I`m going to get flamed for this (is that still a thing?), but why anyone would put any oil in the gas in a modern car with so many sensors, etc., I don`t know. The last time I did that I think I was trying to stop the run-on in my handed-down-from-my-father mid-70`s GM, that would keep knocking on for 5 minutes in the summer. Probably 1981, and that car didn`t have even a 3-way catalyst, no O2 sensors, just the converter. I think I may still have that can of MMO somewhere. You know, in case I need it someday, right Oneheadlite?

[William_Wallace]

All good sect the large write up talked about it as being the same as Lucas, ucl, slight cleaning, lube and protect fuel system offset ethanol and slight gain to fuel Econ. The whole write up was basing it of Lucas and marvel being oils and called for even less of the ashless 2 stroke. Aiming for 1/750 ratio.

This whole thing has a cult like following. I did notice smooth ideal but the whole increase to mpg didn’t happen. I still use mmo once in while before oil change dump some in oil

So I’m thinking I would not advise in hindsight to avoid noobing something up.

when I was replacing the upper and lower intake gaskets my valves were extremely clean though probably from Crc and not having injection direct into chamber. It’s 3.5 duratec with normal injection

[Lonnie]

William-Wallace:
Just another comment on your catalytic converter replacement.
Was this because the CEL (Check engine Light) came on OR just from your on-board computer diagnostic (OBCD) fault-code readings taken after your extensive parts replacements to the fuel intake and emission systems?

It also makes me realize that few vehicle owners are as pro-active about fuel and emission `efficiency" as you are on their high-mileage vehicles. With the average age of a vehicle in the United States being 12.1 years, according to information compiled by the US Department of Transportation from state DMV vehicle registrations, it makes me wonder how many catalytic converter are really "working" these days, considering that a vast majority do not undergo any type of state-required vehicle emission and safety inspections. What is kind of misleading is that we do not know the average odometer mileage these vehicles have actually been driven. Even if you consider that the average mileage a vehicle owner drives is 10,000 miles per year, this would indicate that their are MANY vehicles with over 120,000 miles on them and again I go back to my concern about how many have "working" catalytic converters on them.I can see the federal government stepping in to require ALL states to do this eventually to meet Greenhouse Gas Emission requirements according the Paris Agreement. No inspection, no Federal road funds.
Don`t laugh! The feds did this to the state of Wisconsin when we were the LAST state to have a minimum 19-year-old allowable alcoholic drinking age. When the rest of the US states had raised their minimum drinking age to 21 according to the Federal National Minimum Drinking Age, Wisconsin legislature resisted because of the Tavern League`s lobbyist insistence that this would place "undo economic hardship" on Wisconsin tavern owners and businesses with alcohol beverage selling licenses. The Feds stepped in and economically "blackmailed" the state by saying, "No 21 minimum drinking age, no Federal road funds". The legislature was "forced` to raise the minimum drinking age to 21 which took effect on September 1, 1986

I do see that vehicles are having their catalytic converters stolen in the news recently. Police are suggesting that vehicle owners stamp the VIN on them as a theft deterent, but a grinder can take care of that. Now authorities are targeting metal recycles who take in and pay cash for catalytic converters.

[William_Wallace]

@lonnie it all started with a CEL and rough ideal which lead me to the false hope with air getting in somewhere. I was also seeing decent data on my scan tool the volts on the second sensor wasn’t bouncing back and forth from .2-.8 constantly. I also was surprised both converters did it at the same time. When I clear the codes it takes the computer about 200-300 miles to pop up the check engine light again. To rate my mechanical skills on a list of 1-10 with 10 being highest I’m about a 2

[wannafbody]

MMO is great stuff. I used it to start a tractor that had sat for a couple years. A little in the gas tank and it fired right up. Same story with a friends chainsaw that sat for a year. Messed with it for half an hour. Put some MMO in it and it fired up on the second pull. That being said, it probably isn`t good for a vehicle that burns some oil and has cats.

[William_Wallace]

Look what you guys made me do….test the spacer theory

[Setec Astronomy]

Interesting...in regard to the earlier discussion about visual inspection, I know here in NJ they roll a mirror thing under the car, I always presumed they were just checking to make sure the cat is still there, I`m not sure they are looking closely enough to pick up that spacer, but maybe that`s what they are looking for, IDK.

[William_Wallace]

Interesting...in regard to the earlier discussion about visual inspection, I know here in NJ they roll a mirror thing under the car, I always presumed they were just checking to make sure the cat is still there, I`m not sure they are looking closely enough to pick up that spacer, but maybe that`s what they are looking for, IDK.

maybe I’ll dirty them up so they blend my mechanic is actually a pastor in a different church but I’m catholic I’m gonna tell him in advance don’t want to get on his bad side or give Catholics a bad name! I remember the Seinfeld episode about “finding a good mechanic” then again he know I do some of my own noob work might get a good laugh I have had to have my vehicle towed once because a messed up a transfer case ptu couldnt get it all back together on my suv.

[William_Wallace]

To the posters that mentioned O2 spacers they were 100% right they have been on since my last post and no p0420 or p0430.