Failed emissions for the 3rd time

[bigjim]

I have a 99 2wd 4runner with appx 262K miles on it.
in 2018 NOx was around 0.9 GPM, the max in CO is 2.0 GPM.
2020 rolls around and i have to restest.
Test 1: NOx = 2.082 = fail

Test 2: NOx = 2.27xx = fail
before the test I
--Premium gas
--replaced air filter
--cleaned MAF
--ran seafoam through it

Test 3:NOx = 2.17xx = fail
before the test I
--Ran Guaranteed Pass in tank
--replaced upstream O2 Sensor
--replaced cracked air filter to throttle body boot
--half tank premium gas ran through before the test and tested with less than 1/4 tank

Not sure what else to try aside from a new cat.
Any suggestion on a direct fit replacement?
All the other levels are good

Thanks

 

[mtbtim]

Maybe try a product called Cataclean. It gets mixed reviews but many have had a positive result so it's worth a shot before dropping big coin on a catalytic converter. Amazon.com: Cataclean 120019 Cataclean - The Original Liquid Science - Complete Engine, Fuel & Exhaust System Cleaner: Automotive

 

[Bad Luck]

Use regular gas. Vehicle was designed around regular gas so premium isn't really helping anything.

 

[2TH4IST]

What are the rest of the readings besides Nox?

Nox is created by high combustion temps. Some things that can cause high nox are:

Lean fuel conditions (vacuum leaks, bad or poor injector spray patterns, etc)

Carbon build up in combustion chamber/piston (causes slightly higher compression # causing higher exhaust temps)

Bad cat/cats, 21 year old cats have probably exceeded their service life to be honest. Expensive to replace, but if they are toast, they should be replaced.

You can try all the snake oil out there to get you to pass, but it's best to fix issues that are present.


Also what state are you in? Be aware that you 4runner may be put on the gross polluter list if the emissions are double what is permmited for the 4runner.

 

[sportscarfan]

Use regular gas. Vehicle was designed around regular gas so premium isn't really helping anything.

I disagree. With my 5 speed, using "regular" which is 85 octane here, at low RPM / high load (IE lugging it) you can hear the detonation. I've run 91 in it since noticing this early on after buying it. I attribute this low octane detonation to accounts of others I read that have head gasket problems.

 

[Bad Luck]

I disagree. With my 5 speed, using "regular" which is 85 octane here, at low RPM / high load (IE lugging it) you can hear the detonation. I've run 91 in it since noticing this early on after buying it. I attribute this low octane detonation to accounts of others I read that have head gasket problems.

With higher elevation areas then yes, but elsewhere I stand by using regular gas when called for. With a manual you can lug anything with any gas enough to ping.

 

[bigjim]

What are the rest of the readings besides Nox?

Nox is created by high combustion temps. Some things that can cause high nox are:

Lean fuel conditions (vacuum leaks, bad or poor injector spray patterns, etc)

Carbon build up in combustion chamber/piston (causes slightly higher compression # causing higher exhaust temps)

Bad cat/cats, 21 year old cats have probably exceeded their service life to be honest. Expensive to replace, but if they are toast, they should be replaced.

You can try all the snake oil out there to get you to pass, but it's best to fix issues that are present.


Also what state are you in? Be aware that you 4runner may be put on the gross polluter list if the emissions are double what is permmited for the 4runner.

HC GPM = 0.2109 .......Colorado Limit=1.2
CO GPM = 3.4626........Colorado Limit=15
CO2 GPM = 445.0452.....Colorado no limit
NOx GPM = 2.1749......Colorado Limit=2.000

I am tempted to just spend the 250 on an Eastern Catalytics cat
1999 Toyota 4Runner 3.4L V6, with California emissions Eastern Direct-fit Federal EPA-Compliant Catalytic Converters - FREE SHIPPING - Lowest Price Guaranteed!

BTW i only have 1 cat, the front one

Thanks

 

[jgue467]

Not a bad price and warranty. I'd go for it....

 

[Dieselchessy]

High NOx means your chamber temps are high.

You should flush your coolant system, refill with 50/50 and maybe put in some water wetter.
You should run a tank of gas with a full bottle of Seafoam, maybe 2 tanks with full bottles to clean out any carbon.
Make sure you don't have any vacuum leaks, change your fuel filter, clean the IAC, MAF, and replace O2 sensor. Anything that would cause it to run lean.
When was your timing belt replaced. Any chance timing is off?
Correct plugs installed?
What oil you running and when was it changed? Maybe run some Marvels to remove sludge.
When was the fuel filter changed.
Thermostat installed correctly?

You need to cool the combustion chamber some and prevent pre-ignition.

 

[bigjim]

It is due for a timing belt change, just didn't want to replace it if it wasn't going to pass.

I ordered the Eastern cat from the link above, I'll put that in and see what happens.
O2 sensors are new
MAF was already cleaned
Oil is full synthetic no idea what brand

Thanks

 

[19963.4lsr5]

You might be running lean on a cylinder or two from a clogged injector.

Put a double dose of Techron in it.


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