Catalytic Converter Problems

Steve Zissou

Steve Zissou

New member
Greetings! I've been a T4R reader for about a year now but I've never joined because I haven't had a problem with my 4Runner.....until now. For background, I have a 99 4Runner SR5 4X4 with 56,400 miles.



The problem:

My check engine light popped on and the diagnostic code is P0420 for a catalytic converter. I live in Florida so I don't have to pass any emissions tests so I don't think I need an OEM cat.

My questions are:

My truck is still running fine and I haven't noticed a drop in MPG so how long can I go before replacing it?

How will I know when to replace it? Will it start sounding like a harley or will I notice a drop in MPGs?

Also, has anyone bought any aftermarket catalytic converter and if so, which brands/models are the best? I'm willing to spend a little more to get a higher quality new one. Here's a website I was looking at.... Catalytic Converter - Auto Parts Warehouse



Thanks for your time and answers in advance!
 
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WELCOME to the forum.

56K on a '99--wow...I have 135K on mine and that's relatively low.

It really depends on why you have the P0420. The possible causes are:
1. Exhaust leak before rear sensor
2. Bad rear sensor
3. Bad front sensor (rare, absent any other code)
4. Bad cats.

I ordered these in terms of cost to fix, low to high. The first thing is just reset the ECM to clear the code, and see how long it takes to come back. It could be a bad tank of gas or other anomaly.

In most cases, no MPG or performance issue is associated with a P0420--other than the silly light. The exception is a really plugged up cat which can really cause problems. This frequently results in a tell-tale sulphur smell at the exhaust, so check for that. Then check carefully for exhaust leaks, as this can frequently be a cheap fix.

If you are not bothered by the light, don't have emissions testing, and don't care about the environment, you can really ignore it as long as the car runs fine.

You can try changing the rear sensor, if you want the MIL to go away. They usually go at 70K+ but yours has 11 years on it. This cured my P0420. A good mechanic with a live OBD monitor can diagnose this. There is also a simulator available from URD (not street legal) which will fool the ECM back into submission. Search on 'URD sim' for more info.

I strongly recommend that you keep your stock cat(s) until you are SURE they are the problem. They are very expensive and after-market cats just don't work as well. The originals rarely fail at your mileage unless the car has been poorly maintained (unburnt fuel from a rich mix will kill a cat) or physically damaged. Yet lots of dealers, shops, etc. will happily rip them out when they were not the real problem.
 
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I had the code cleared yesterday at 3 pm and it came back on while driving around 11:30 pm (probably 25 miles of driving and 3 start-ups later). I'll check for the sulfur smell later today. How would I diagnose an exhaust leak?

And forgive my ignorance, what do MIL and OBD stand for?

Thank you for your quick response. It's encouraging that it may not be my cat. I average 18 gallons/tank consistently, which probably is not indicative of a rich fuel mix, right? (I'm unfamiliar with vehicle/motor operations so I apologize if these questions seem dumb). Thanks.
 
Steve Zissou said:
I had the code cleared yesterday at 3 pm and it came back on while driving around 11:30 pm (probably 25 miles of driving and 3 start-ups later). I'll check for the sulfur smell later today. How would I diagnose an exhaust leak?

And forgive my ignorance, what do MIL and OBD stand for?

Thank you for your quick response. It's encouraging that it may not be my cat. I average 18 gallons/tank consistently, which probably is not indicative of a rich fuel mix, right? (I'm unfamiliar with vehicle/motor operations so I apologize if these questions seem dumb). Thanks.
Click to expand...

Exhaust leak--I use a piece of paper and run it along the exhaust system while motor is running. Look for movement--if there is a suspect area hold it there and it will discolor if there's a leak. Don't burn yourself. Things get real hot. Also look for physical signs: broken bolts, holes, abrasions, etc. Or just take it to a muffler shop and ask to check for leaks only. Don't let them sell you a new cat--yet.

MIL and OBD--what he said.^^^^

Rich mix--it could have happened sometime in the past. How long have you owned it?
 
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Steve, I don't know if my input will help as I am not a good mechanic like several people on this site. But I will be making a post about my Cat / CEL issues today in a new thread. I have a 2000 3.4 as well.
 
Clogged Cats

Hello Everybody,

I'm new to T4R.ORG and I believe I have a clogged Catalytic Converter on Bank 1...I was diving down the road and as I accelerated, the vehicle bogged out a bit...I took temp reading before and after the cat (On Both Sides) and there was no difference in the temperature. So I pulled off all cats and shined at light through them, 3 of the 4 were clear, but bank 1 exhaust manifold cat was definitely clogged...I cleaned it with hot soapy water and ammonia. It seamed to clear the honeycomb a bit, so I reinstalled all the cats. Also none had damage to the honeycomb on the inside. Upon driving again, my 4Runner has no power...I accelerate and there is no or slow response. Can Anybody lend me a bit of advice or has anybody experienced this before? I own A 2003 V6 4.0L 4Runner. Finally, when I took the cat temps after driving it, the before temps were around 700+ and the aft were around 200+.

Frustrated Owner
 
wow
I did not know the newer 4runners, but the above sounds more like my sons Honda pilot with a bunch of cats
My 2000 v-6 has only one cat, I know the cali ones can have 2 cats....but 4 cats....really ?
wow....no thanks
 
Hyfyer1 said:
Hello Everybody,

I'm new to T4R.ORG and I believe I have a clogged Catalytic Converter on Bank 1...I was diving down the road and as I accelerated, the vehicle bogged out a bit...I took temp reading before and after the cat (On Both Sides) and there was no difference in the temperature. So I pulled off all cats and shined at light through them, 3 of the 4 were clear, but bank 1 exhaust manifold cat was definitely clogged...I cleaned it with hot soapy water and ammonia. It seamed to clear the honeycomb a bit, so I reinstalled all the cats. Also none had damage to the honeycomb on the inside. Upon driving again, my 4Runner has no power...I accelerate and there is no or slow response. Can Anybody lend me a bit of advice or has anybody experienced this before? I own A 2003 V6 4.0L 4Runner. Finally, when I took the cat temps after driving it, the before temps were around 700+ and the aft were around 200+.

Frustrated Owner
Click to expand...

You may get a better response if you post your question in the 4th gen section of this forum instead of here in the 3rd gen section. Your 2003 truck is a 4th gen.

Anyways, good luck I'm sure someone will advise you.
 
I am having a similar problem with my 2002 SR5. It has 366k. About six months ago, I got a CEL with P0420 just like the OP. I cleared it and it came back a week later. I cleared it again and it has not come back. Then, two days ago it had a very rough acceleration after a cold start and the CEL came on for a few seconds then went out. I turned off the engine, turned back on, and it was still a little rough but not too bad. The next day it was much better but still rough/missing(?)/chugs when pressing the gas hard. Once it gets up to speed it runs perfectly smooth. There is no CEL and no codes to be found by the code reader. Here's what I've tried so far with no noticeable improvement:
-Sea foamed gas tank, oil, manifold
-changed oil (after 150miles of sea foam)
-replaced air filter
-cleaned MAF sensor
-cleaned throttle body
-checked all vacuum tubes
-put fuel injector cleaner in gas tank

Based on some of the forum advice, I'm considering replacing the fuel filter. It was last replaced 130k miles ago. I am also considering replacing the MAF (although I think it's good, but can't be sure). Finally, I saw some advice saying the cam position sensor could be the culprit. I've seen some advice to replace coils and plugs but if one of those things were bad then I think I would get a CEL and code. The plugs were replaced 130k ago and the coils are original. I'm not thinking it is the cat, however, I did get a P0420 some time ago.

Please provide this new forum member any advice on this problem. Thanks!
 
highmile said:
I am having a similar problem with my 2002 SR5. It has 366k. About six months ago, I got a CEL with P0420 just like the OP. I cleared it and it came back a week later. I cleared it again and it has not come back. Then, two days ago it had a very rough acceleration after a cold start and the CEL came on for a few seconds then went out. I turned off the engine, turned back on, and it was still a little rough but not too bad. The next day it was much better but still rough/missing(?)/chugs when pressing the gas hard. Once it gets up to speed it runs perfectly smooth. There is no CEL and no codes to be found by the code reader. Here's what I've tried so far with no noticeable improvement:
-Sea foamed gas tank, oil, manifold
-changed oil (after 150miles of sea foam)
-replaced air filter
-cleaned MAF sensor
-cleaned throttle body
-checked all vacuum tubes
-put fuel injector cleaner in gas tank

Based on some of the forum advice, I'm considering replacing the fuel filter. It was last replaced 130k miles ago. I am also considering replacing the MAF (although I think it's good, but can't be sure). Finally, I saw some advice saying the cam position sensor could be the culprit. I've seen some advice to replace coils and plugs but if one of those things were bad then I think I would get a CEL and code. The plugs were replaced 130k ago and the coils are original. I'm not thinking it is the cat, however, I did get a P0420 some time ago.

Please provide this new forum member any advice on this problem. Thanks!
Click to expand...
130k on your plugs? Change them now! Because you did get a CEL but it went out and 130k on plugs is ridiculous. I change every 30k. Sounds like an intermittent miss, and plugs and wires are first suspect. Did you check for stored codes or are you just going by the lack of a CEL?

In a case like this I will first LOOK at the plugs. Keep track of which one went where. If any are black, super clean, oily, discolored, or have gas on them, then that is something that has to be addressed. There is no better x-ray to engine health than a look at the plugs.

While you are at it, inspect and ohm out the wires and look at the coil boots (they can be changed separately). Look for any evidence of breaks in the insulation or tracks from wayward voltage. If the wires are the factory Sumitomos with the year on the insulation, you probably want new ones. The above may not fix it, but I would do it before trying anything else.
 
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Thanks TheDurk

TheDurk, Thanks for your advice. I am going to replace the plugs and will also check the wires and coil boots. To answer your question, there is not a CEL and when I checked with a code reader there are no codes and no pending codes. I've checked now for about 4-5 days of driving and still no codes. The wires and coils are both original. 366k later maybe they're not working so great anymore huh!? :) Engine seems to be running better after the first day which was running really bad, but it still misses/is sluggish especially when cold or when pressing gas hard. Will let you know the results once I replace plugs and check the wires/coils. It's crazy to me that there is no CEL and no codes for this issue.
 
2000 4runner 3.4L V6 in need of CA approved CAT for engine code ending in 4XBP

Does anyone know how I could get a cat that would work for this particular engine? I can only find Cats that are approved for FFM.

I have been told i can only find at the dealership for $1995 (wow). Does anyone know where i could buy a used one that would work?

I cant seem to find anything and im getting worried that people in CA just dont use this car once the CAT goes out of Smog approval.

Thank you all for your help with this.

Best regards,
-Chris.
 
Chris Taylor said:
Does anyone know how I could get a cat that would work for this particular engine? .
Click to expand...

Walker makes Carb compliant cats but they identify the 2000 T4R 3.4L V6 as Engine Family # YTYXT03.4FFR. Is your engine different?

Link to their e-catalog look-up...perhaps the entering the VIN would be the best way to go.....
WALKER® EXHAUST SYSTEMS :: E-Catalog Lookup

FYI...you can buy these through Amazon...

Buckaroo
 
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Cat Issue

Good time to jump in here - have a 1999 with 193k on it, well maintained. The P0420 code for the catalytic converter has been coming on for years (father-in-law had truck first, said he first had it in 2004).

Anyway, it's gone years of coming on, going off after battery reset and being off for various length of time. Just replaced exhaust on it over weekend, new battery, CEL reset and 120 miles later, CEL back on. Have code reader coming tonight to see it's something else. I know front 02 sensor is good and mechanic has checked MAF and other parts.

Any recommendations to help if it is the CAT? Have NJ inspection coming up next month - it's passed before so going to try clearing and then hurrying through drive cycles. Unfortunately, catalyst "not ready" is an auto-fail in NJ...

Also, anyone ever use CataClean? I figure I'd give it a try but I don't want to damage the engine or really ruin cat.

And people who say "well, it might be time to get rid of it" have never known what it's like to own a 4runner!
 
The periodic P0420 is something that happens on these trucks, particularly when driven at slow speeds. Don't rule out the possibility of exhaust leaks until you have checked thoroughly. If factory, those metal exhaust gaskets are turning to dust at this point. A lot cheaper than new cats.

Also, you don't say how old the rear sensor is. If you changed the front, but not the rear, then I would change it straight away. That's all it does is set the P0420. Changing it cured mine.
 
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Thanks! Will give a look to the rear sensor.

Haven't had any drop in fuel economy (actually, doing pretty well these days) and exhaust system is brand new. We usually get more than 120 miles out of it before CEL. Have code reader/clearer now and hope to clear it and pass the drive cycles before it comes back on.
 
Hey everybody. Long-time creeper, first time poster. Has anyone had a resolution to their issues? I'm having similar troubles with my 2002 3.4L.

Background: A few months ago I was having rough starting and idling. Ended up cleaning the MAF sensor and TB thanks to help from this site :) The rough idle went away and rough starting became intermittent (after engine has been warm). I've also now got an intermittent P0420 code (pending code and actual CEL). I replaced plugs, wires, purge solenoid, A/F, and O2 sensors within the past year (~10k mi). My exhaust stinks and seems to be burning rich but the cats don't rattle (I think--I may be in denial about the cats).

The rough starting and code may be independent of each other but I've read on a thread that the fuel pressure regulator may be the culprit to the rough starting and rich mixture (and therefore the code--in my mind at least). Also, after cleaning the TB I did forget to reconnect the FPR vacuum line for a day or so of driving (oops).

I have an ultragauge ODB reader and according to that, my bank 1, sensor 1 (A/F) ratio sits around 1.0 consistently (1="ideal mixture" according to ultragauge) and bank 2, sensor 2 (O2) fluctuates 0-.8V

Just wondering if anyone had any success and what their solution may have been or if anyone has further advice. Thanks!
 
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