[jfpizzaman]

This site seems like the best place to ask, but I've posted before and didn't get the best answers

I have tried spark plug spacers, and a resistor/capacitor hack to alter the sensor reading, but nothing has worked - still getting the SES light. It looks like I'm going to have to buy a new driver's side front cat.

CAN ANYONE RECOMMEND THE LEAST EXPENSIVE CARB-CERTIFIED (CALIFORNIA) CAT OUT THERE?? THANKS!!

 

[phatB]

sounds like you're trying to work around an issue. are you sure it isn't an o2 sensor? have you pulled the code?

 

[jfpizzaman]

Not absolutely sure, but the code is 0430, and the right side cat appears to have been changed (very shiny and new looking, while the driver's cat looks old. Almost 300k on the truck (I recently purchased). Thanks for the help.

 

[phatB]

ah that's a lot of miles, I'm not surprised if it reached it's end of life, and since you can see the passenger side cat has already been replaced then you're probably right. the usually don't make it to 200k.
looking online yep looks like you need a new cat. might be able to avoid the SES (if you don't care about the cat not working) by installing an o2 sensor spacer on the sensor before the cat to move it out of the exhaust stream...

 

[Skibane]

might be able to avoid the SES (if you don't care about the cat not working) by installing an o2 sensor spacer on the sensor before the cat to move it out of the exhaust stream...

Or relocate the O2 sensor to the side that's already had the cat replaced - right next to the existing O2 sensor...

ETA: In theory, the O2 sensor wire to the bad side could probably be re-connected to the existing O2 sensor behind the working cat instead, so that both sides were connected to the same, working sensor.

However, in practise, having two sensor inputs connected in parallel to the same sensor probably loads it down too much to get an accurate O2 measurement.

 

[smj999smj]

I didn't think there was an aftermarket C.A.R.B. certified option for the 4.0L Frontiers? I thought the only choice was a new, genuine Nissan replacement?

 

[rodhotter]

even though you "trick" the computer + keep the check light off reading the computer will see that "readiness" is not set + you are not legal!!

 

[smj999smj]

I wouldn't mess around with re-wiring or spacing the front O2 sensors, keeping in mind these sensors are critical for fuel management by the ECM. Some use spacers or CEL eliminators on the rear O2 sensor(s) to trick the ECM, which will usually allow the SRT to complete, but, if seen, will fail state inspection in California as it is technically "tampering." If you have a vehicle that has CA emissions but is not registered and operated in California or a state that uses similar emissions inspection, then the converter does not need to be C.A.R.B. certified and you can use the much less expensive, aftermarket options.

 

[jfpizzaman]

Magnaflow 558665 is supposed to be CARB certified. $350.

 

[jfpizzaman]

Clever idea Skibane - putting 2 sensors on the new cat. Thanks. Adding a mounting port is out of my wheelhouse. I am considering buying the cheap out-of-state cat and registering in nevada.

 

[jfpizzaman]

Thanks phatB it had spark plug anti-foulers on it when I bought it.

To take the cheating a step further: What if I went with the far cheaper non - California CARB - rated cat, and registered out of state, or even in California? Will it pass California emissions? Thanks!

 

[rodhotter]

the front sensor regulates the air-fuel ratio, second one checks cat efficiency! even a good but overly good cat that outflows the original can trigger a code. tough states that access your ECU can see a stored code + you are SOL!!!

 

[jfpizzaman]

Thanks rodhotter - in that case there must already be stored codes in my ECU. I'm curious what others may have done to avert what seems to be an inevitable expensive repair.

 

[rodhotter]

i have a VagCom for my 2001 audi TT, had it since 2002 just after i bought my 2001 jetta new, it does more that i can safely do. i clear codes, but when you check deeper there is a section called readiness codes + after a complete town a highway driving cycle it will say ready IF all is correct pollution wise, or not. that can likely be checked at the hardcore inspection stations in calif, here in pa in my county a visual check is all that is done. a savy station can spot the fowler mod + refuse you. the best way is if you can get an exhaust system where the cat section is easily replaced + unless theres bolt on flanges a never rust 300 series stainless system is required + band type clamps that dont indent pipes preventing easy removal. i used to switch downpipes for offroading on a car as the 3" hi flow cat triggered a light, but the 2.5" standard aftermarket cat was good. for 9 years i would swap pipes easily pulling the slip fit connections apart, thats 304 stainless!!

 

[BWitt]

Magnaflow 558665 is supposed to be CARB certified. $350.

Do you know the Magnaflow part number for the right or passenger side converter as well?

 

[Sixspeed-SV]

CARB compliant three way catalytic converters are tricky to find at a reasonable price. 128k on the clock and mine are smoked. The labor charge for replacement is a tall number. Stock units are most likely the way to go. Magna Flow units 5582665 and 5582668 are asking $2300 a piece. Nissan parts deal are asking $800 each but, they do not state directly that they are CARB units as my rig is CA registered.