Aftermarket Catalytic Converter(s) for '02 Montero

Inyo_man

Explorer
Greetings,

After over 230K miles, I'm considering replacing the cats. on my 2002 Montero.
Currently, I'm looking for reviews/feed-back on after-market products.
When rebuilding my kid's '86 Toyota Pickup, we installed a Walker system (complete with Cali. Cat.). It has met my expectations, however, I'm interested to hear what folks are using in their Generation. III Montero.

All suggests/questions/comments are welcomed!
Cheers
 

Inyo_man

Explorer
...so, everyone is still running factory installed Cats. on their Gen. 3?
Not sure about the rest of the states, but in California we have been blessed with three Cats. in our Montero.
 

plh

Explorer
...so, everyone is still running factory installed Cats. on their Gen. 3?
Not sure about the rest of the states, but in California we have been blessed with three Cats. in our Montero.
3 cats in my "05 not Cali. Still original. Installed O2 non-foulers several years ago. Currently at 190K+
 

Salonika

Monterror Pilot
I know you are asking about Gen 3 but a cat is a cat. Original cats on my Gen 2.5, 225k. My truck came from Cali so I have 3 cats as well but only the upstream cats are sensored. Clean running well maintained motors extend the cat life. I have started to get an occasional P0421 / P0420 in the past 5 years or so but only on long drives with highway. I clear it out and it doesn’t come back for 6 months. Why are you wanting to replace them?
 

Inyo_man

Explorer
Thanks for the reply.
I'm getting P0431 (cat. not getting to proper temp.). The O2 sensors were replaced in the last 80K, so I wasn't thinking this was the issue, but I've still got to test them. I don't think it's a vacuum leak, because when I clear the code, it doesn't pop on for a few days.
Hoping I don't need to replace the Cats., but doing some research, just in case.

Cheers
 

Michael Brown

You followed me, so now we're both lost
I had this code intermittent for a while before replacing the bank 1 sensor with an Denso one from RockAuto. Haven't seen the code since then, but it may come back with colder weather. I had used a cheaper one off of eBay (4 sensors for $80), but that only got me about a year before it quit working.
 

chentwoten

New member
I just picked up a 2000 Montero and was dealing with the same P0431 issue (Warm Up Catalyst Efficiency Below Threshold)

I recommend using an OBD2 scanner with live data to check your O2 voltage readings to compare Sensor 1 (upstream) and Sensor 2 (downstream) for each bank.

You should see consistent readings (purple and red lines) on the downstream sensors if the catalytic converters are working properly. If they're all over the place, the cat may need to be replaced (which it was in my case, see difference in purple lines).

Also, if you consider replacing your cats for California smog, the smog techs are supposed to (read: not all will) check for the CARB E/O# on the replacement cats to verify the correct cat for the vehicle (and placement on vehicle). You can use the following link to reference by inputting your vehicle information.

https://ssl.arb.ca.gov/AftermarketParts/catalysts

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RyanY

Adventurer
I've used CataClean once with good results - it's far cheaper than replacing the cats so it's probably worth trying first.
If you do end up replacing them keep in mind that there are 49 state legal and 50 state legal cats. There are tons of cheap Chinese 49-state cats available but my experience is that they have short lifespans and aren't worth the savings when they need to be replaced again in 3-4 years. I would only recommend using 50-state legal cats as they seem to be better quality.
 

Inyo_man

Explorer
I had this code intermittent for a while before replacing the bank 1 sensor with an Denso one from RockAuto. Haven't seen the code since then, but it may come back with colder weather. I had used a cheaper one off of eBay (4 sensors for $80), but that only got me about a year before it quit working.
Thank for the reply! I also replaced my sensors with Denso. It would be a much easier/cheaper repair if I don't have to replace the cat(s).
I plan on looking into the issue this weekend. Fingers crossed it is a sensor...
 

Inyo_man

Explorer
I've used CataClean once with good results - it's far cheaper than replacing the cats so it's probably worth trying first.
If you do end up replacing them keep in mind that there are 49 state legal and 50 state legal cats. There are tons of cheap Chinese 49-state cats available but my experience is that they have short lifespans and aren't worth the savings when they need to be replaced again in 3-4 years. I would only recommend using 50-state legal cats as they seem to be better quality.
I figure that was the case...since I'm in California, I'll likely get a "Cali. Cat.", if I ended up replacing them.
Thanks for the tip on CataClean! I may give it a try...

Cheers
 

Inyo_man

Explorer
I just picked up a 2000 Montero and was dealing with the same P0431 issue (Warm Up Catalyst Efficiency Below Threshold)

I recommend using an OBD2 scanner with live data to check your O2 voltage readings to compare Sensor 1 (upstream) and Sensor 2 (downstream) for each bank.

You should see consistent readings (purple and red lines) on the downstream sensors if the catalytic converters are working properly. If they're all over the place, the cat may need to be replaced (which it was in my case, see difference in purple lines).

Also, if you consider replacing your cats for California smog, the smog techs are supposed to (read: not all will) check for the CARB E/O# on the replacement cats to verify the correct cat for the vehicle (and placement on vehicle). You can use the following link to reference by inputting your vehicle information.

https://ssl.arb.ca.gov/AftermarketParts/catalysts

View attachment 612579View attachment 612580
This is excellent information, and greatly appreciated. (Although, the link does not seem to work...I'll start searching.)
I'm armed and ready for diagnosis this weekend (after I button up some work on the VW's front end)
Cheers.
 

Inyo_man

Explorer
Starting this thread I was preparing for the worst case...failed cats.
After running some diagnostics (live check with the UltraGauge), the sensors appear to be working fine.
It looks like I've skated through this issue without depleting the wallet.
The rig is due for a smog inspection this year (Dec.), so I figured I had time to fuss with this problem before throwing too much money at it.
P0431 kept popping on, so I just kept clearing the code with the UltraGauge.
Finally, a couple of weeks ago, the code stopped appearing. Of course, I was skeptical, and was merely waiting for the code to pop once again.
Well, about two weeks went by, and my DMV notice arrived. I took it down to my buddy's shop for a smog check...It passed without issue.
Celebration...I'm good for another two years.
...still not sure what the issue was.
Thanks for all of the input!
Cheers
 
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