catalytic converter change
 

had a p0420 pop up i cleared it and put catyclear in the tank today because the cat system is 430$ for oem was wondering if this doesnt work....probably wont can you delete the factory dual cats and replace it with an aftermarket magnaflow single cat where the resonator is? or would that cause more with the O-2-the crappy gas mileage sensors

That's not a resonator. It's an un-monitored cat and has a matrix in it. I thought mine was rattling so we cut it off and it's not baffled, but has a catalytic matrix in it so we welded it back on. One of the muffler baffles was rattling.

I'll bet you have a CA system, don't ya? NY requires all new cars after 99 to be CA compliant. Dual cats and 4 02s, right? Federal is 2 cats, 2 02s, and only 1 downstream 02. The Federal system requires PCM re-programming if switching from CA system. Also the CA system requires specific 02 sensors that are more expensive than the Federal ones.

3 I have 1 upstream 2 downstream right before the little cats I was going to put the magnaflos on but they won't fit in that location

I sounds like you've got the Federal system then. My CA system has 2 little cats right under the brake booster with an 02 before and after each one, then the big can before the muffler. I put a shorter muffler from a 97 ZJ on it and it makes to sound a little better. At least I can hear how the engine is running now. I may replace this rattling thing with a Flowmaster, but I've got to keep in sound level down because I deliver newspapers late at night.

Nah I just got to looking I have the ca version 2 top 2 bottom so I'm basically stuck with oem replacement but I did find stainless on summit from magnaflow for 437$ so I may go with that and tube manifolds and a port polish , having a 6* advance flash done should net me roughly 27-28 highway with the 235s I'm getting 24-26 now with a ram air and #24 quadport injectors and it's snappy as hell even with tires at 31.7 inches high

And I have a thrush welded it's the same thing as a flow Master 40 but less cost has a nice deep growl can't say rumble 4.0 doesn't rumble it growls

ok so i did not see it was against forum rules to discuss this until recently i apologize..... i will be doing an oem replacement when and if needed not deleting the cats

It isn't against the rules to talk about catalytic converters anymore, so you are good. Also 24-26 mpg is hard to believe, is that hand calculated or going off of the lie-o meter?

It was before the 235/85s spent 75$ at 2.75 a gallon down to NC and back which was 785 miles it equals 26.58 mpg all highway this was with adjusted tv cable #24 injectors and 6* timing advanced I will probably get about 23.3 or so with the lift and larger tires it may increase a hair or stay the same due to lower rpm I get now (was running 1950rpms factory tires now at 1650ish with larger tires )

You would honestly be surprised what you can get with a pcm recalibration which I have to have again since the larger tires due to speedo difference

Just for information, in 2016 I made a trip from Syracuse NY to Rochester NY on the Thruway at 90+*F, round trip 195 miles including about 20 miles on surface streets before the return. I took a friend to pick up a truck he had bought, had lunch, then returned.

The road was basically flat, air temp was 95* with light wind from the west, no A/C with all 4 windows down, 245/70R16 tires, 3.55 gearing, 3 souls on board going out, 1 returning, running a constant 70 mph. The road was thru the Montezuma National Wildlife Refuge so the air was humid. Jeep had 195K miles on it with a new head. No other mods. It was recalled for a PCM reflash, intake manifold heat shield, and seat belt shoulder bolts.

Actual fuel mileage calculated by odometer reading and actual fuel usage was 27.42 which shocked me! The VIC said 26.2. I normally get 16.2 around town in the summer and 12 in the winter, less when doing my paper route. This is the only road trip I've ever made with this vehicle so far. OH... and I used the same gas station for both fill-ups.

Yeah the EPA estimated is wrong 18 town and 22 highway for the 4.0 I run 3:55s as well I may have to go 373s not sure yet

One thing I do that may sound strange is on those lonely, dark, hilly country roads at night I lock out O/D. That way I get quicker throttle response and speed control at about 40-45 and it gives me time to react to deer-in-the-headlights!

I typically cruise at 40 highway I do 60 unless stated 55 so I'm not well liked in NC where it's 75mph cause I will do like 64-67

Yeah, on the interstate I set my cruise at 68 and let people pass me if they like. I had my speedo checked by police stationary radar in the towns of Dewitt and Manlius and it reads 2-3 mph faster than the radar at various speeds. That's with 29.5" diameter tires.

I'm thinking of installing a Flowmaster 50. I want to hear how my engine is running but don't want to wake up my newspaper customers. What do you think? You're right about the sound a 6 makes. It's not the nice rumble of a V8.

As long as you have all your cats a thrush welded works good it's 38.88 at advanced Auto and it's equal to a flow Master 40 and not loud at all you can barely hear it going down the road and at idle it's got a nice low tone grumble

I had a pair of Flowmaster 40s on my 87 Chevy truck (350) and it sounded nice, but I got complaints about the noise in my up-scale neighborhoods. Some of these houses cost 1 mil or more. I don't drive more than 25 mph on the route but they could still hear me at 3 AM. To quiet it, I stuck a pair of Cherry Bombs on the ends of the tailpipes inside some thin tubing that slid over them. I think they were about 4". I was using a pair of cheap cats designed for the 4.3 S10.

No those rules have been relaxed. There is a post from the moderator on that.

Just a heads up on the PO420 cat codes. ALL CARS have the cat converter under full warranty dealer replacement for 8 years or 80,000 miles. Federal law. Regardless of ownership or original owner.
Just got my moms 2010 honda crv replaced basically for free with the po420 code, all they needed to see was the code on the scanner and no questions asked they replaced it.
Nothing is free tho, they still managed to charge $90. for clamps and hardware. Still saved about 2g.

I'm starting to think my emmisions code may have been triggered by larger tires I've drove this for 2 months everything fine even after the lift I checked my milage from when I put the tires on exactly 100 miles which is enough time for the system to do a check I also have wheel sensor 1234 out of spec I'm wondering with the California emissions if I have to have pcm recalibration for that because of the lower rpm at higher speeds making the pcm think I'm jumping in fuel when I'm not because the cats are clear and the O2 sensors check out fine and are within factory specs

Don't think so. PO420 in my experience means the cat is plugged.
Like I said before the dealer replaced ours at no charge with no further troubleshooting than to verify the code PO420.
There are all kinds of posts stating the O2 sensor, etc etc. None are right. If the O2 sensor wasn't working, you wouldn't get a code.
One way to tell is the make a couple additives for the gas tank that will clear the cat temporarily. One is called 'Guaranteed to Pass" . I used this twice. Both times it cleared the code for a month or so. Long enough to pass emissions inspection tho.

Well your free or at no charge doesn't work for me fist off this is a 2000 so it's 18years old the odometer has 170k on it even though it's got a crate motor with 6k and the exhaust and cats are oem

That and I stated everything was fine till the 32inch tires and low highway rpms and I also stated cats are clear my backpressure is within spec and my o2 sensors are working properly my fuel mileage is the same 18-19 town 23-25 highway I may get a set of walker procats and throw on for ****s and giggles since they are 135$ a piece rather then 600-800 for the cats and down pipe or since my state requires only fed visual inspection I may just delete the Cal cats splice the wires to the down stream and run it after the downstream cat

You're welcome, I think.
I am aware you have a 2000 and never said you can get a free one.
I think you're on the right track to replace it. Or both as you have two.
Toss a bottle of Guaranteed to Pass in it, like $12. See if the code goes away for a month or two.

I've already cleared the code and dumped. 4 bottles of catyclear in it in the past week still comes back

So I went and got a brand new snapon obd reader/recalibration tool this one showed graphs instead of fluctuating numbers turns out 02 s2b2 had no power too it hmmm..... So I bought a new sensor plugged it in and boom check engine light gone turns out the connections were broke inside the connector but my cheapo scan tool did not pick up on that problem solved everything is in check and even recalibrated to speedo myself

The catalytic converter is not usually a wear item. If it has deteriorated than there should be an underlying reason, such as;

"Leaded fuel was used where unleaded was called for (unlikely).

A damaged or failed oxygen / O2 sensor Downstream oxygen sensor (HO2S) wiring damaged or connected improperly.

The engine coolant temperature sensor is not working properly.

Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe.

Failed or underperforming catalytic converter (likely).
Retarded spark timing.

The oxygen sensors in front and behind the converter are reporting too similar of readings.

Leaking fuel injector or high fuel pressure Cylinder misfire Oil contamination"

the problem has been solved....if you didnt read my old scanner couldnt pick up the variations the new scanner could it was 02s b1s2 it was replaced..and for fuel milage i went 848 miles yesterday cost me 87$ for the round trip for a total of 23.86 mpg highway at 65mph the whole way on 235/85/16s would of done better but the hills got me with the 355 gears i probably will gear up to 373

Glad you fixed it! The code is generic and the issue was with one of the underlying reasons, that is why i posted.

Just a heads up, 2010 CRV with 60k miles, the PO420 WAS the cat. They did not look any further at the dealership, just ordered and replaced the cat. Said they get a few a month like that. Not supposed to happen, thats why the fed mandates a universal 8 year of 80k mile warranty. The dealer would not be giving away a $2k job for $99 otherwise.

My cats were clear the O2 was messed up from the factory motor having a crack in the head and causing issues before I purchased the vehicle with a brand new crate motor and trans so it's had a few things that should have been but were not replaced such as sensors it's not always the cat typically cats are a life of vehicle non service but with the condition of the rust on the exhaust and my old code reader not picking up the variations in the O2 sensor I thought it was the cat but the engine temp and back pressure ratio being normal left me confused

Question; how do you measure back pressure ratio?

You have a specific pressure that is released from the exhaust valve not sure how exactly the dealer measured it but they said it is within spec

Yeah, I'm aware of what it is, but IDK how you measure it. Also, is it a ratio of exhaust pressure compared to atmospheric or pressure difference above and below the cats and/or muffler?

It's below the cats but before the muffler my brother explained to me because he's done it a few times that they use a compression tester at the downstream 02 socket and the motor is hand cranked through each cylinder

Okay....so that's a static test for system restrictions, I guess. Being downstream I don't know what it proves. I'd be curious of a dynamic test comparing upstream and downstream pressures to determine possible cat blockage.

The reason I'm asking this question is my engine burns a little oil but it seems to be just at idle and the tailpipe smokes just a little only then. The exhaust smells weird then, but the engine doesn't seem to lack power and I get good fuel mileage. My muffler has a loose baffle that rattles and I thought it might be the big downstream cat, but we cut it off and inspected it. It's perfectly clean and not loose so we welded it back on. That cat is not monitored at all. IDK about the condition of the upstream cats.

I need to install an oil catch can in the CCV system to see if that helps with my oil problem.

im not entirely sure i was up for 22 hours when he was explaining this to me( will get a better explanation after sleep) but i have an idea of your rattle i had a rattle chatter chirp going on sounded like a bad muffler when i was sitting idle or in gear going slow i noticed the tail pipe was just touching the heat shield for the gas tank i stuck a prybar in the hanger in the back and pushed the tail pipe towards the outside of the vehicle and tada the chirp rattle was gone

Nope. Mine's inside the muffler. Up on the lift, you can bang on the muffler with the side of your fist and it rattles. It's a cheap Soundmaster that's 2 years old.

I like your thinking !!! The 3.73s are what I was thinking. Factory or Canyon wheels 15x8 with 31x10.50x15s and 3" lift. I found a great link to compare them side by side!!! http://www.grimmjeeper.com/gears.html With the 3.73s would be even better mileage with 31s. Less RPM at most speeds ! I try to keep mine under 2100. I'm really concerned about the fuel economy too. You said #24 injectors ,,, 4-hole Bosch??? Anyone tried the 12- hole models ? Going with a banks header and 2.5 back with new hi-flo cat and muffler. Not sure which muffler ? Really like the wheels Cruiser linked. I been watching a set in charcoal on ebay,,, $361 shipped !!! Would rather have the silver ones. I also keep looking at the American Racing AR23s. Really like these !!!