Replacement Catalytic Converter

[jodomcfrodo]

Hi all,
I've been forced to get my catalytic converter fixed because I'm moving to a state with emissions testing. I've had the P0420 code for over 5 years now. Recently, I had a dealer install a new converter, but the code is still present. I think this is because the converter the dealer put in is the cheapest one available (I didn't know that at the time). Since there are so many converters available online, does anyone have any input as to which company makes one that will actually work? I'm pretty sure it is the cat because I've already replaced O2 sensors (although if there is anything else that would cause a P0420 code, I'd be up to hear ideas about that as well).

Thanks!

 

[Northwood]

First off, if the dealer intended to fix your code and did not, bring it back and let them deal with it.

How long has it been since they did the repair and was the light on or off when you left the dealer? It will take some time for the code to reset automatically if the dealer didn't do so although I would expect they would have cleared it.

Out of curiosity what brand o2 sensors did you use when you replaced them? Hopefully NTK/NGK and not Bosch

I went with eastern catalytic when I did mine but I did all three cats at once

https://www.rockauto.com/en/catalog...6,exhaust+&+emission,catalytic+converter,5808

 

[jodomcfrodo]

First off, if the dealer intended to fix your code and did not, bring it back and let them deal with it.

How long has it been since they did the repair and was the light on or off when you left the dealer? It will take some time for the code to reset automatically if the dealer didn't do so although I would expect they would have cleared it.

Out of curiosity what brand o2 sensors did you use when you replaced them? Hopefully NTK/NGK and not Bosch

I went with eastern catalytic when I did mine but I did all three cats at once

https://www.rockauto.com/en/catalog...6,exhaust+&+emission,catalytic+converter,5808

It's a long story with that dealer. They're idiots and I'm 2500 miles away from them right now. I'm not doing any business with them anymore.


The code reappeared 2 miles from the dealer after the new cat was put in. I had a more reputable shop put the 02 sensors in around a month later but it still didn't fix the code.

This was 9 months ago but I put it off to fix it until now.

I'll take a look at that link. I know my precats look pretty terrible right now as well.

 

[Northwood]

Your pre cats are the only ones that will throw a code. So if they only replaced the main cat that would have done nothing to fix your problem.

P0420 catalyst system efficiency below threshold (bank 1)
Meaning the bank 1 pre cat, closest to the front of the engine, is not functioning as it should.
There is also a possibility the downstream 02 sensor in bank 1 is bad but normally that would throw a different code

 

[Chris]

What brand of O2 sensors are you using?

 

[jodomcfrodo]

What brand of O2 sensors are you using?

I'm not sure to be honest. I had a local mechanic change them for me. He owned a 4.0l himself so I'm assuming he used some good 02 sensors. If I can find the receipt, it'll probably tell me. But I had them replaced around October or November and nothing changed so I think they might be alright.

Your pre cats are the only ones that will throw a code. So if they only replaced the main cat that would have done nothing to fix your problem.

P0420 catalyst system efficiency below threshold (bank 1)
Meaning the bank 1 pre cat, closest to the front of the engine, is not functioning as it should.
There is also a possibility the downstream 02 sensor in bank 1 is bad but normally that would throw a different code

I never changed the pre-cats, so those are probably the issue. I didn't know that PO420 referred to the pre-cats. I told the dealer that I had 420 and they said they would replace the main catalytic converter. Guess they didn't know what they were doing (pretty much the usual for them I guess).

How was your luck with eastern catalytic? Just from looking at their website, they seem to know what they're doing.

 

[Slepnir]

I had a p0420 code pop up after replacing the downstream o2sensor. Jeep ran fine though. I kept reading everyone telling me to replace the cat so i checked the temp above and below the cat and there was nothing abnormal but i still wanted to be sure so i did a pressure test upstream and down steam and there was no signs or restriction. Replaced the o2 sensor upstream because i read that since one was new and the other was old there could be a difference in sensitivity. Anyways the code still popped up and i gave it the finger, but after a few days it went away and never came back and the jeep is still running fine and code hasn't returned. Sooo give it the finger lol.

 

[Chris]

Here's the thing, unless you are using NGK / NTK O2 sensors (you can see this thread to know which ones you should be using), there are large numbers of people who report issues with anything other than those O2 sensors. In fact, this is a very well documented issue.

I am bringing this up because that could be the issue. I don't know for sure, but I would definitely find out for 100% certain what brand of O2 sensors were put in there.

When I replaced my pre-cats (which are known to fail at higher miles), I replaced them with the Walker brand. I've had them on for 20k miles now give or take, and never had an issue.

The Walker cats for your 2001 model are Walker part number 53461:
https://www.amazon.com/dp/B000VKXBLE/?tag=wranglerorg-20

 

[jodomcfrodo]

I had a p0420 code pop up after replacing the downstream o2sensor. Jeep ran fine though. I kept reading everyone telling me to replace the cat so i checked the temp above and below the cat and there was nothing abnormal but i still wanted to be sure so i did a pressure test upstream and down steam and there was no signs or restriction. Replaced the o2 sensor upstream because i read that since one was new and the other was old there could be a difference in sensitivity. Anyways the code still popped up and i gave it the finger, but after a few days it went away and never came back and the jeep is still running fine and code hasn't returned. Sooo give it the finger lol.

My CEL has been on for 5 years with the 420 code so I don't think it'll go away any time soon lol.

Here's the thing, unless you are using NGK / NTK O2 sensors (you can see this thread to know which ones you should be using), there are large numbers of people who report issues with anything other than those O2 sensors. In fact, this is a very well documented issue.

I am bringing this up because that could be the issue. I don't know for sure, but I would definitely find out for 100% certain what brand of O2 sensors were put in there.

When I replaced my pre-cats (which are known to fail at higher miles), I replaced them with the Walker brand. I've had them on for 20k miles now give or take, and never had an issue.

The Walker cats for your 2001 model are Walker part number 53461:
https://www.amazon.com/dp/B000VKXBLE/?tag=wranglerorg-20

I have 220,000 miles on my jeep with stock pre-cats. Changing the 02 sensors from stock to new ones did nothing at all so I'm going to rule those out for now. I'll try to find my receipt to figure out which ones I have. My pre-cats look pretty rough from just looking at them so I might as well replace them.

 

[Chris]

I have 220,000 miles on my jeep with stock pre-cats. Changing the 02 sensors from stock to new ones did nothing at all so I'm going to rule those out for now. I'll try to find my receipt to figure out which ones I have. My pre-cats look pretty rough from just looking at them so I might as well replace them.

Definitely replace the pre-cats then.

However, if that doesn't do it, my money is on the O2 sensors.

But let us know if replacing the pre-cats does it. 220k miles on the stock pre-cats wouldn't surprise me at all if they were toast. Those things probably aren't good for much more than 120k.

 

[Northwood]

My CEL has been on for 5 years with the 420 code so I don't think it'll go away any time soon lol.



I have 220,000 miles on my jeep with stock pre-cats. Changing the 02 sensors from stock to new ones did nothing at all so I'm going to rule those out for now. I'll try to find my receipt to figure out which ones I have. My pre-cats look pretty rough from just looking at them so I might as well replace them.

It would be worth the minute or so it would take to look for a brand stamped on your O2 sensors before you spend all that cashola on pre cats. Not saying you don't needs pre cats, you probably do, but a malfunctioning upstream O2 sensor can cause your brand new cats to fail prematurely so I would want to be damn sure you've got NGK/NTK sensors in there

My pre cats went out right at 100k lol so your doing way better than I did

 

[Fouledplugs]

I'm not sure to be honest. I had a local mechanic change them for me. He owned a 4.0l himself so I'm assuming he used some good 02 sensors. If I can find the receipt, it'll probably tell me. But I had them replaced around October or November and nothing changed so I think they might be alright.




I never changed the pre-cats, so those are probably the issue. I didn't know that PO420 referred to the pre-cats. I told the dealer that I had 420 and they said they would replace the main catalytic converter. Guess they didn't know what they were doing (pretty much the usual for them I guess).

How was your luck with eastern catalytic? Just from looking at their website, they seem to know what they're doing.

Running that long in open loop has prob made a significant impact on your O2 sensors and cats. My advice would be to actually find out what the problem is with a scanner that has live data to look at. Doing so, will give you a better idea of where to start.

I really feel running open loop that long has taken it's toll on your O2 sensors and cat for sure.

I never grasp the concept of running engines without proper working sensors in place to keep the engine in a good healthy state and tune....very negligent.

 

[Fouledplugs]

It would be worth the minute or so it would take to look for a brand stamped on your O2 sensors before you spend all that cashola on pre cats. Not saying you don't needs pre cats, you probably do, but a malfunctioning upstream O2 sensor can cause your brand new cats to fail prematurely so I would want to be damn sure you've got NGK/NTK sensors in there

My pre cats went out right at 100k lol so your doing way better than I did

X's 2

 

[jodomcfrodo]

Running that long in open loop has prob made a significant impact on your O2 sensors and cats. My advice would be to actually find out what the problem is with a scanner that has live data to look at. Doing so, will give you a better idea of where to start.

I really feel running open loop that long has taken it's toll on your O2 sensors and cat for sure.

I never grasp the concept of running engines without proper working sensors in place to keep the engine in a good healthy state and tune....very negligent.

It wasn't my decision to not change the catalytic converter. The light came on when I was around 10 years old! But the jeep ran and still does run fine. In a state with no emission testing, it doesn't really make sense to change a cat, especially when the Chrysler version is $1400.

I'm going to replace the pre-cats and go from there.

 

[Fouledplugs]

It wasn't my decision to not change the catalytic converter. The light came on when I was around 10 years old! But the jeep ran and still does run fine. In a state with no emission testing, it doesn't really make sense to change a cat, especially when the Chrysler version is $1400.

I'm going to replace the pre-cats and go from there.

While I understand your concern when it comes to the OEM prices and your age. I wasnt trying to say it was our fault. A lot of people do the same thing and think no big deal. I hope you are not seeing this as an argument. I hope everyone will do their own research on this.

Having bad cats and O2 's can cause your engine to run very rich.
You say it runs fine. What was your gas milage like?

 

[jodomcfrodo]

While I understand your concern when it comes to the OEM prices and your age. I wasnt trying to say it was our fault. A lot of people do the same thing and think no big deal. I hope you are not seeing this as an argument. I hope everyone will do their own research on this.

Having bad cats and O2 's can cause your engine to run very rich.
You say it runs fine. What was your gas milage like?

Oh no no! I wasn't trying to make an argument out of it. For the most part, I agree, it should have been fixed earlier. Just giving the reasoning behind not getting around to it before.

On my cross country road trip, going around 70-75 mph, I got around 225 miles per tank. I think it was around 13 or 14 mpg overall, which I don't think is too bad.

 

[Chris]

For going 70-75 mpg that gas mileage is reasonable.

On all flat terrain going about 60, I can average 18-20 mpg over 200 miles. But that's almost entirely flat highway.

 

[jodomcfrodo]

For going 70-75 mpg that gas mileage is reasonable.

On all flat terrain going about 60, I can average 18-20 mpg over 200 miles. But that's almost entirely flat highway.

That brings up another post I was going to make. How smooth is your jeep at 70mph? I have a 3 inch lift, custom driveshafts, and an SYE but I still get slight vibrations at 70. My center mirror gets blurry at those speeds. Should I expect the jeep to be completely smooth or are some vibrations expected at those speeds?

 

[Chris]

That brings up another post I was going to make. How smooth is your jeep at 70mph? I have a 3 inch lift, custom driveshafts, and an SYE but I still get slight vibrations at 70. My center mirror gets blurry at those speeds. Should I expect the jeep to be completely smooth or are some vibrations expected at those speeds?

It should be completely smooth, mine is.

If you're experiencing vibrations like that, it's almost certainly improperly balanced tires. Most shops aren't good at balancing large tires like we run, and because of that a lot of people end up spending lots of time and money chasing down vibrations, that they believe to be death wobble. However they almost always end up being in properly balanced tires.

 

[jodomcfrodo]

It should be completely smooth, mine is.

If you're experiencing vibrations like that, it's almost certainly improperly balanced tires. Most shops aren't good at balancing large tires like we run, and because of that a lot of people end up spending lots of time and money chasing down vibrations, that they believe to be death wobble. However they almost always end up being in properly balanced tires.

I've had driveline vibrations before and they felt similar to this. It's not a wobble like unbalanced tires. I'll run it down to the jeep shop sometime soon. Thanks for the help!