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2002 Honda Accord EX - needs catalytic converter

Last November, we purchased a 2002 Accord EX from family. A couple weeks before we took ownership of the vehicle, they purchased a newer model Accord, and in the parking lot of the dealership the Accord (now ours - then theirs) refused to start. It was almost comical timing.

It turned out the catalytic converter had given way. That was not so comical. It had about 152k miles at the time. Now even though we live in California, we were still in good shape to take over the vehicle. First, no smog was required since the vehicle was being transferred within immediate family (a DMV allowable exemption). Also, we live in a county that does not require biannual inspection with registration. We could conceivably (and hopefully figuratively) drive it into the ground and never have cause to worry about the CC.

However this summer other family gifted us an F150, and soon afterward a friend approached us interested in the Honda.

So now the catalytic converter is biting us in the proverbial rear. Supposedly it would take about $1200 to have Honda repair (replace?) the part, so naturally I’m looking for more organic solutions. One such solution on YouTube was to at least try running a gallon of furyl acrylic thinner into the tank when the tank is about half full and then run the car for 150 miles. Another was disconnecting the converter and giving it an overnight soaking in a car wash detergent solution. I’m not terribly mechanically inclined, but given the right instruction manual can take on many jobs.

When we got the Honda, we were a 1-vehicle family, so it came at a really nice time. We have 3 small kids and live a few miles from “town.” However, now we have 3 cars and our perspective has changed a little bit. The Mrs. feels duped by my family. You know how the brothers like to work in relationship advice into their car repair issues. But we agreed to the purchase about 2-1/2 months before we actually took ownership of the vehicle. It was only 2-3 weeks before this that the converter tripped the check engine light. They even allowed us to wait 6 weeks after that to begin making $200/month 0% payments (it’s currently half paid off).

What can we do about the converter? As for my wife vs. her in-laws, this will also go a long way to repair that tender connection.

You should post the OBDII code so members can better evaluate your problem. Is it P0420? I’ve seen your proposed “repair” demonstrated on a Youtube video by Scotty Kilmer and have actually tried the detergent solution. It was for a 1999 Odyssey but it did not work for me. To be fair I didn’t let it soak overnight like I should have. Anyway, it depends on what is wrong with the catalytic converter as to whether these methods have a chance to work. Also, depending on the code or codes, it might not be the converter itself but perhaps a downstream oxygen sensor.

I suppose you don’t have much to lose by trying either method. If you remove the converter, you should also replace the inlet and outlet gaskets.

the Accord (now ours - then theirs) refused to start. …
It turned out the catalytic converter had given way.

The catalytic converter will only interfere with starting the engine if it’s plugged. And then, if the car starts, it will barely be drivable.

All those gimmicks for “restoring” converters have been discussed in great detail in past threads in this forum. Don’t hold your hopes up.
One that does have merit is faking out the rear sensor with spark plug non-fouler adapter, though remember that modifying emission systems is not known to be legal.

As AlanY noted, please get your Check Engine Light code read and post it here.

Refusing to start because of a catalytic converter, not really conceivable. They had to replace something else to get it running. I have heard of people having good luck with Cataclean and it can be purchased on Amazon. The other option would be an aftermarket converter, which would be much cheaper the the OEM Honda version.

I had a car towed to the shop that wouldn’t start that was caused by a melted/plugged converter.


If you need a new catalytic converter, try a private shop (not dealer). They could save money by using an aftermarket unit and carbon steel pipes. After all, it doesn’t need to last you another 11 years.

Can’t use aftermarket converters in California.

I presume the Accord hasn’t been used since it failed to start that one time, as the cat was never replaced. Do I understand this right? If so, probably first thing I’d do is temporarily remove it, replace with a straight pipe, and make sure it starts and run well. You want to make sure replacing it will fix the problem.

If that works, then you know a new cat will get you back on the road. And no loss (other than doing so may be illegal) to try some of the cat revitalizer ideas if you want to experiment on your old cat. I doubt they will work though. Certainly don’t expect them too. The cat works b/c of the surface properties of the metal bits inside there, and when the surface gets contaminated, it forms a chemical bond which will prove very difficult to remove I expect. The contaminant is blocking the surface, that’s why it isn’t working. And during the failure, the metal bits may have fused together from the heat, again blocking the surface chemistry from working.

If my car and I wanted it back on the road, and had limited funds, and I knew a replacement cat was what I needed, I’d probably check to see if I can get a used one from a junk yard. If a no go, I’d price the aftermarket cats available, make sure the one I choose meets Calif emissions standards – visit Calif Bur of Auto Repair website for that – and just pay what is necessary I guess.

Thanks, everyone!

FWIW, the code was P0420

We live just 20 miles from the OR state line, and so I may try to list it there. There is nothing mechanically wrong with the car, and the cat converter is not affecting the operation of the car, just the amount of so-called pollution.

I have also found this catalytic converter but I don’t know anything about the company. For those familiar with California’s stringent regulation on these, this find is “50-state legal” and has an EO number that links straight to the BAR.

Thanks for all the input so far. Other thoughts on the aftermarket model here would be helpful. The local mechanic said he’d install it and it’s just 1 hour labor.

Also, to clarify your point @GeorgeSanJose, the initial diagnosis was nearly a year ago. It was just before we took ownership of the vehicle from my folks. It was rotten timing on one hand, but also fortuitous on another, as the fact that it was a family transaction meant California didn’t require a smog check. Also the county where I live does not require ongoing smog checks for registration renewal.

So I am looking at one of two options, now: get the CA-legal converter and sell it to our friend (a transaction that would run about $400), or list it in Oregon (20 miles north) where there is no smog certification required.

Still not sure you need a cat. Google “Honda OBD-II P0420” and read about the various causes.

That cat you list looks like it is CA legal, you could also look on Rockauto.

Ok, I see, when the car didn’t start initially, you thought it was b/c of the cat , but discovered later the cat wasn’t the cause of the non-start. hmmm … well, I think if you can get it back on the road for a $400 cat plus install, that would make some sense. You could then sell it in California. Seems a lot easier than trying to sell it over the border in Oregon.

One other idea, maybe try contacting Honda. Cats usually last longer than 10 years & 150 K. I don’t think Calif requires cats to be warrantied for 10 years, 7 or 8 I think is what they require, but Honda may be able to offer something to help you out, part of Honda customer relations. They want you to consider to buy a Honda in the future, so they want to keep you on their good side. No harm in asking anyway.

@texases - what is your experience with They have - by far - the lowest price of a CA-legal converter I’ve found. Sometimes that’s a good thing but sometimes it’s suspect.

@GeorgeSanJose - if it’s a matter of spending $400 to be able to sell it in CA as opposed to selling it in OR where no cat converter repair would be needed, given that we’re only 20 miles away that seems like a pretty good proposition. But I like your thought about contacting Honda. I will consider that, as well.

I have bought some parts from them, they’re as trustworthy as any. If they had the cat I needed I’d use them.

My comment may not be accepted well, but based on the tale as related I think your wife has the wrong attitude about blaming family members over this car and any problems it suffers, or suffered.

The same might be said if this car is sold to your friend who may decide after the fact that they were duped also if problems continue or the car goes belly-up a few weeks after purchase.

As to your options that’s hard to say. You state the car is half paid off, there’s no idea if a converter will be the final word on the problem, and how much this friend is prepared to pay for the car once (hopefully) repaired.
Current mileage has not been stated but the odds of Honda stepping in on a converter Good Will warranty are about zero.

If more is owed on the car than it will ever be worth even repaired then I might say just cut bait and list it in Oregon. Just my 2 cents anyway.

I wouldn’t buy the catalytic converter and then take it to the mechanic for installation. If it is legal to use aftermarket parts, he should have access to them. If anything goes wrong, then you have recourse.

@ok4450 - I agree with you. Current mileage is about 164k. I’d like to honor the attempted deal with our friends first, as he has offered to help with part/repair (just an hour labor for this piece) and help get it smog-worthy. If there are any hiccups, though, I’m inclined to go north of the state line.

@jtsanders - good point. I will confirm that he’s willing to go through rockauto (the part I found was a Bosal part).

In case anyone cares(-ed), came through very well for me. Mechanic friend installed the cat, I drove it 50+ miles to make sure all the codes were legit, then got it into a smog certification and it passed easily. Smog guy obviously knew it was a new purchase and asked me a few questions about it. Asked who put it in and where I got it. He wasn’t drilling me, nor was he in a position to make a judgment call other than what the computer says. However there is a DRM number on all the parts and only CA-legal converters can be authorized to pass smog. He told me he’s seen far too many come in with 49-state converters and even though the vehicle itself might still pass smog, it’s against CA law.

Rockauto rocked. The car rocked the smog check and we rocked the car sale as hoped! Appreciate all the insight you guys gave on this, too.