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Hey fellow yoats! So I took my recently acquired 96 4runner to the dreaded smog shop only to fail a 2nd time! It failed the 15mph test with high NOx and HC. I gave it a pretty good tune up before going. Cleaned the MAF sensor, throttle body, then ran some seafoam through the intake before changing out plugs, wires, front o2 sensor, and fuel filter. I got better results but still no pass.
I'm thinking now it's gotta be the cat. I looked underneath and I'm pretty sure I only saw a single cat. Is it supposed to have 2? It has California legal stickers under the hood so I'm not sure what it should have. If it is a single cat does anyone have any opinions of the new lcengineering 50 state legal cat? Any help is greatly appreciated!
Last edited by metalmadness24; Apr 16, 2016 at 11:24 AM.
Upon further searching and searching it seems the 96 model year is supposed to be the only model year that is CA legal with one cat.... but I kept finding conflicting information. Can anyone shed some light on the subject?
Could you post up the numbers? It is odd that you have high NOx and HC with a good tune up, for anything other then the CAT. However, if you have high HC and the second O2 sensor is not picking it up then the second O2 is bad. Look at it this way, the O2 is cheaper then a CAT, so that is were I would start, and the my guess is the new O2 sensor will trip telling you the CAT is bad.
There is no other real world way to have both high NOx and HC in the combustion chamber other then not being catalyzed
Just to add to this California EPA standards confusion and single Cat conversation, I'm in Canada and here is my 99' EPA sticker, 1 cat, 1 up stream A/F sensor, 1 down stream 02 sensor. What does your emissions sticker say out of curiosity. I doubt a different ECU and sensors where used for California only just an extra Cat but I've been wrong before.
Just to add to this California EPA standards confusion and single Cat conversation, I'm in Canada and here is my 99' EPA sticker, 1 cat, 1 up stream A/F sensor, 1 down stream 02 sensor. What does your emissions sticker say out of curiosity. I doubt a different ECU and sensors where used for California only just an extra Cat but I've been wrong before.
You do NOT have an A/F sensor or a Cali. truck. See my response in the other thread:
Good to know, interesting they ask $260 A/F/02 sensor at Toyota, and the rear an 02 for $150 and all this time they are slightly different types of 02's that do the same thing with extreme price difference, sounds fishy.
Apr 16, 2016 | 11:21 AM
